OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 24 — Nov. 21, 2011
  • pp: 23878–23888
« Show journal navigation

Absolute frequency list of the ν3-band transitions of methane at a relative uncertainty level of 10−11

Sho Okubo, Hirotaka Nakayama, Kana Iwakuni, Hajime Inaba, and Hiroyuki Sasada  »View Author Affiliations


Optics Express, Vol. 19, Issue 24, pp. 23878-23888 (2011)
http://dx.doi.org/10.1364/OE.19.023878


View Full Text Article

Acrobat PDF (1389 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We determine the absolute frequencies of 56 rotation-vibration transitions of the ν3 band of CH4 from 88.2 to 90.5 THz with a typical uncertainty of 2 kHz corresponding to a relative uncertainty of 2.2 × 10−11 over an average time of a few hundred seconds. Saturated absorption lines are observed using a difference-frequency-generation source and a cavity-enhanced absorption cell, and the transition frequencies are measured with a fiber-laser-based optical frequency comb referenced to a rubidium atomic clock linked to the international atomic time. The determined value of the P(7) F2(2) line is consistent with the International Committee for Weights and Measures recommendation within the uncertainty.

© 2011 OSA

1. Introduction

Precise frequency measurements of molecular vibrational transitions have provided fundamental knowledge of molecular physics and physical chemistry. They have contributed to verifying fundamental physics [1

1. J. L. Hall, C. J. Bordé, and K. Uehara, “Direct optical resolution of the recoil effect using saturated absorption spectroscopy,” Phys. Rev. Lett. 37(20), 1339–1342 (1976). [CrossRef]

4

4. B. Darquié, C. Stoeffler, A. Shelkovnikov, C. Daussy, A. Amy-Klein, C. Chardonnet, S. Zrig, L. Guy, J. Crassous, P. Soulard, P. Asselin, T. R. Huet, P. Schwerdtfeger, R. Bast, and T. Saue, “Progress toward the first observation of parity violation in chiral molecules by high-resolution laser spectroscopy,” Chirality 22(10), 870–884 (2010). [CrossRef] [PubMed]

], determining fundamental constants [5

5. C. Daussy, M. Guinet, A. Amy-Klein, K. Djerroud, Y. Hermier, S. Briaudeau, ChJ. Bordé, and C. Chardonnet, “Direct determination of the Boltzmann constant by an optical method,” Phys. Rev. Lett. 98(25), 250801 (2007). [CrossRef] [PubMed]

, 6

6. G. Casa, A. Castrillo, G. Galzerano, R. Wehr, A. Merlone, D. Di Serafino, P. Laporta, and L. Gianfrani, “Primary gas thermometry by means of laser-absorption spectroscopy: determination of the Boltzmann constant,” Phys. Rev. Lett. 100(20), 200801 (2008). [CrossRef] [PubMed]

], testing theoretical ideas for calculating of molecular energy levels [7

7. P. Jensen and P. R. Bunker, eds., Computational molecular spectroscopy, (John-Wiley and Sons Inc., New York, 2000).

], and establishing frequency standards [8

8. G. Guelachvili and K. Narahari Rao, Handbook of Infrared Standards (Academic, Orlando, Fla., 1986). G. Guelachvili and K. Narahari Rao, Handbook of Infrared Standards II (Academic, Orlando, Fla., 1993).

, 9

9. T. J. Quinn, “Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001),” Metrologia 40(2), 103–133 (2003). [CrossRef]

]. They are also necessary for qualitative and quantitative analysis in extensive applications such as the chemical industry, atmospheric science, medical diagnostics, and astronomy [10

10. S. Svanberg, Atomic and molecular spectroscopy: Basic aspects and practical applications, 4th edition (Springer Verlag, Berlin, 2004).

, 11

11. J. Tennyson, Astronomical spectroscopy: An introduction to the atomic and molecular physics of astronomical spectra, (World Scientific Publishing Co. Inc., Singapore, 2010).

]. Databases of molecular transitions such as HITRAN [12

12. L. S. Rothman, I. E. Gordon, A. Barbe, D. Chris Benner, P. E. Bernath, M. Birk, V. Boudon, L. R. Brown, A. Campargue, J. P. Champion, K. Chance, L. H. Coudert, V. Dana, V. M. Devi, S. Fally, J.-M. Flaud, R. R. Gamache, A. Goldman, D. Jacquemart, I. Kleiner, N. Lacome, W. J. Lafferty, J.-Y. Mandin, S. T. Massie, S. N. Mikhailenko, C. E. Miller, N. Moazzen-Ahmadi, O. V. Naumenko, A. V. Nikitin, J. Orphal, V. I. Perevalov, A. Perrin, A. Predoi-Cross, C. P. Rinsland, M. Rotger, M. Simeckova, M. A. H. Smith, K. Sung, S. A. Tashukun, J. Tennyson, R. A. Toth, A. C. Vandaele, and J. Vander Auwera, “The HITRAN 2008 molecular spectroscopic database,” J. Quant. Spectrosc. Radiat. Transf. 110(9-10), 533–572 (2009). [CrossRef]

] and GEISA [13

13. N. Jacquinet-Husson, N. A. Scott, A. Chédin, L. Crépeau, R. Armante, V. Capelle, J. Orphal, A. Coustenis, C. Boonne, N. Poulet-Crovisier, A. Barbe, M. Birk, L. R. Brown, C. Camy-Peyret, C. Claveau, K. Chance, N. Christidis, C. Clerbaux, P. F. Coheur, V. Dana, L. Daumont, M. R. De Backer-Barilly, G. Di Lonardo, J. M. Flaud, A. Goldman, A. Hamdouni, M. Hess, M. D. Hurley, D. Jacquemart, I. Kleiner, P. Köpke, J. Y. Mandin, S. Massie, S. Mikhailenko, V. Nemtchinov, A. Nikitin, D. Newnham, A. Perrin, V. I. Perevalov, S. Pinnock, L. Régalia-Jarlot, C. P. Rinsland, A. Rublev, F. Schreier, L. Schult, K. M. Smith, S. A. Tashkun, J. L. Teffo, R. A. Toth, V. G. Tyuterev, J. Vander Auwera, P. Varanasi, and G. Wagner, “The GEISA spectroscopic database: Current and future archive for Earth and planetary atmosphere studies,” J. Quant. Spectrosc. Radiat. Transf. 109(6), 1043–1059 (2008). [CrossRef]

] are based mostly on near- and mid-infrared spectroscopy of vibrational transitions and microwave spectroscopy of rotational transitions. The spectral linewidth of the former is usually limited by Doppler broadening of the order of one hundred megahertz, whereas that of the latter is determined by pressure broadening of the order of a few hundred kilohertz. Therefore, microwave spectroscopy provides more accurate data for the rotational structure of the ground vibrational state than infrared spectroscopy. However, detailed investigations are especially difficult for non-polar molecules that have no rotational transitions.

Sub-Doppler resolution infrared spectroscopy was carried out using predominantly gas lasers such as a He-Ne laser at 3.4 μm (88 THz) [14

14. J. L. Hall and J. A. Magyar, “High resolution saturated absorption studies of methane and some methyl-halides,” in High-Resolution Laser Spectroscopy, K. Shimoda ed. (Springer-Verlag, Berlin, 1976).

], CO2 and N2O lasers in the 10 μm (30 THz) region, and a CO laser in the 5 μm (60 THz) region because they have the strong output with a narrow linewidth and the absolute frequencies of the oscillation lines were precisely measured [9

9. T. J. Quinn, “Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001),” Metrologia 40(2), 103–133 (2003). [CrossRef]

, 15

15. A. Amy-Klein, H. Vigué, and C. Chardonnet, “Absolute frequency measurement of 12CO2 laser lines with a femtosecond laser comb and new determination of the 12CO2 molecular constants and frequency grid,” J. Mol. Spectrosc. 228(1), 206–212 (2004). [CrossRef]

17

17. T. George, W. Urban, and A. Le Floch, “Improved mass-independent Dunham parameters for the ground state of CO and calibration frequencies for the fundamental band,” J. Mol. Spectrosc. 165(2), 500–505 (1994). [CrossRef]

]. However, the narrow tunable range has prevented from comprehensive analysis of a vibrational band extending more than 3 THz. Microwave sideband CO2- and CO-laser systems [18

18. G. Magerl, J. M. Frey, W. A. Kreiner, and T. Oka, “Inverse Lamb dip spectroscopy using microwave modulation sidebands of CO2 laser lines,” Appl. Phys. Lett. 42(8), 656–658 (1983). [CrossRef]

, 19

19. B. Meyer, S. Saupe, M. H. Wappelhorst, T. George, F. Kühnemann, M. Schneider, M. Havenith, W. Urban, and J. Legrand, “CO laser side-band spectrometer: Sub-Doppler heterodyne frequency measurements around 5 μm,” Appl. Phys. B 61, 169–173 (1995). [CrossRef]

] contributed to extending the tunable range in the 10 and 5 μm regions, but no complete analysis of a vibrational band has been reported thus far. Recent progress of mid-infrared sources such as quantum cascade laser diodes [20

20. J. T. Remillard, D. Uy, W. H. Weber, F. Capasso, C. Gmachl, A. L. Hutchinson, D. Sivco, J. Baillargeon, and A. Y. Cho, “Sub-Doppler resolution limited Lamb-dip spectroscopy of NO with a quantum cascade distributed feedback laser,” Opt. Express 7(7), 243–248 (2000). [CrossRef] [PubMed]

], optical parametric oscillators [21

21. E. V. Kovalchuk, D. Dekorsy, A. I. Lvovsky, C. Braxmaier, J. Mlynek, A. Peters, and S. Schiller, “High-resolution Doppler-free molecular spectroscopy with a continuous-wave optical parametric oscillator,” Opt. Lett. 26(18), 1430–1432 (2001). [CrossRef] [PubMed]

], and difference-frequency-generation (DFG) in waveguide devices of nonlinear optical elements [22

22. O. Tadanaga, T. Yanagawa, Y. Nishida, H. Miyazawa, K. Magari, M. Asobe, and H. Suzuki, “Efficient 3-μm difference frequency generation using direct-bonded quasi-phase-matched LiNbO3 ridge waveguides,” Appl. Phys. Lett. 88(6), 061101 (2006). [CrossRef]

] has extended the frequency range to which sub-Doppler resolution spectroscopy can be applied. It reduces the observed spectral linewidth to a level similar to that of microwave spectroscopy. It is, however, difficult to determine the transition frequency as accurately as the spectral linewidth because the required relative accuracy of frequency measurements is three orders of magnitude higher than that in microwave spectroscopy.

Optical frequency combs (OFCs) have reduced the technical difficulties of optical frequency measurements [23

23. D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis,” Science 288(5466), 635–639 (2000). [CrossRef] [PubMed]

], which had been carried out in only a few laboratories of standards. The measurable frequency range has extended over the spectral range of the OFCs towards longer and shorter wavelength regions through nonlinear optical processes [24

24. T. Yasui, Y. Kabetani, E. Saneyoshi, S. Yokoyama, and T. Araki, “Terahertz frequency comb by multifrequency-heterodyning photoconductive detection for high-accuracy, high-resolution terahertz spectroscopy,” Appl. Phys. Lett. 88(24), 241104 (2006). [CrossRef]

, 25

25. T. J. Pinkert, D. Z. Kandula, C. Gohle, I. Barmes, J. Morgenweg, and K. S. E. Eikema, “Widely tunable extreme UV frequency comb generation,” Opt. Lett. 36(11), 2026–2028 (2011). [CrossRef] [PubMed]

]. In particular, the frequency of the DFG source is easily measured using the OFC because the carrier-envelope offset frequency of the OFC does not have to be controlled. In practice, the combination of the mid-infrared DFG source and the OFC has determined the transition frequencies for Doppler-limited [26

26. D. Mazzotti, P. Cancio, A. Castrillo, I. Galli, G. Giusfredi, and P. De Natale, “A comb-referenced difference-frequency spectrometer for cavity ring-down spectroscopy in the 4.5 μm region,” J. Opt. A, Pure Appl. Opt. 8(7), S490–S493 (2006). [CrossRef]

28

28. P. Maddaloni, P. Malara, E. De Tommasi, M. De Rosa, I. Ricciardi, G. Gagliardi, F. Tamassia, G. Di Lonardo, and P. De Natale, “Absolute measurement of the S(0) and S(1) lines in the electric quadrupole fundamental band of D2 around 3μm,” J. Chem. Phys. 133(15), 154317 (2010). [CrossRef] [PubMed]

] and sub-Doppler resolution spectroscopy [29

29. D. Mazzotti, P. Cancio, G. Giusfredi, P. De Natale, and M. Prevedelli, “Frequency-comb-based absolute frequency measurements in the mid-infrared with a difference-frequency spectrometer,” Opt. Lett. 30(9), 997–999 (2005). [CrossRef] [PubMed]

31

31. G. Giusfredi, S. Bartalini, S. Borri, P. Cancio, I. Galli, D. Mazzotti, and P. De Natale, “Saturated-absorption cavity ring-down spectroscopy,” Phys. Rev. Lett. 104(11), 110801 (2010). [CrossRef] [PubMed]

].

We developed a 3.4-μm DFG spectrometer for sub-Doppler resolution saturated absorption spectroscopy [32

32. M. Abe, K. Takahata, and H. Sasada, “Sub-Doppler resolution 3.4 microm spectrometer with an efficient difference-frequency-generation source,” Opt. Lett. 34(11), 1744–1746 (2009). [CrossRef] [PubMed]

]. It consisted of an efficient waveguide-type periodically-polled lithium-niobate (PPLN) [22

22. O. Tadanaga, T. Yanagawa, Y. Nishida, H. Miyazawa, K. Magari, M. Asobe, and H. Suzuki, “Efficient 3-μm difference frequency generation using direct-bonded quasi-phase-matched LiNbO3 ridge waveguides,” Appl. Phys. Lett. 88(6), 061101 (2006). [CrossRef]

], which was irradiated by pump and signal waves from a 60-kHz wide 1.55-μm distributed-feedback (DFB) laser and a 5-kHz wide 1.064-μm Nd:YAG laser. While the DFG source was frequency-stabilized at the saturated absorption line of the ν3 band transition of 12CH4, the absolute frequencies of the pump and signal waves were measured using the OFC based on a mode-locked erbium-doped fiber laser (fiber comb) made by ourselves for frequency measurements [33

33. T. R. Schibli, K. Minoshima, F. L. Hong, H. Inaba, A. Onae, H. Matsumoto, I. Hartl, and M. E. Fermann, “Frequency metrology with a turnkey all-fiber system,” Opt. Lett. 29(21), 2467–2469 (2004). [CrossRef] [PubMed]

, 34

34. H. Inaba, Y. Daimon, F. L. Hong, A. Onae, K. Minoshima, T. R. Schibli, H. Matsumoto, M. Hirano, T. Okuno, M. Onishi, and M. Nakazawa, “Long-term measurement of optical frequencies using a simple, robust and low-noise fiber based frequency comb,” Opt. Express 14(12), 5223–5231 (2006). [CrossRef] [PubMed]

]. We determined 12 transition frequencies of the P(7) and P(6) lines with a typical relative uncertainty of 9.4×10−11 [30

30. K. Takahata, T. Kobayashi, H. Sasada, Y. Nakajima, H. Inaba, and F. L. Hong, “The absolute frequency measurement of sub-Doppler molecular lines using a 3.4-μm difference-frequency-generation spectrometer and a fiber-based frequency comb,” Phys. Rev. A 80(3), 032518 (2009). [CrossRef]

]. The tunable range of the DFG spectrometer was about 350 GHz limited by the DFB laser. Subsequently, the 1.55-μm source was replaced by an external-cavity laser diode (ECLD), which is tunable over 28 THz but more unstable in frequency than the DFB laser. Therefore, we have introduced a cavity-enhanced absorption cell (CEAC) as a reference for both frequency stabilization and linewidth reduction of the ECLD. At the same time, the CEAC enhances the optical field amplitude at the antinodes and the effective absorption length, and thus enables us to carry out highly sensitive saturated absorption spectroscopy [35

35. J. Ye and J. L. Hall, “Absorption detection at the quantum limit: Probing high-finesse cavities with modulation techniques,” in Cavity-enhanced spectroscopy, Experimental methods in the physical sciences vol. 40, R. D. van Zee and J. P. Looney ed. (Academic Press, San Diego, 2002).

]. Indeed, we have resolved the hyperfine structure of more than 20 rotation-vibration transitions of the ν1 band of CH3I [36

36. S. Okubo, H. Nakayama, and H. Sasada, “Hyperfine-resolved 3.4-μm spectroscopy of CH3I with a widely tunable frequency generation source and a cavity-enhanced cell: A case study of a local Coriolis interaction between the v1 = 1 and (v2, v6l) = (1, 22) states,” Phys. Rev. A 83(1), 012505 (2011). [CrossRef]

].

2. Experimental apparatus

The experimental setup of the spectrometer is depicted in Fig. 1
Fig. 1 Experimental setup of spectrometer. ECLD: external-cavity laser diode, EOM: electro-optic modulator, FA: fiber amplifier, XO: crystal oscillator, PPLN: periodically poled lithium niobate, BW: Brewster’s window, λ/4: quarter-wave plate, CEAC: cavity-enhanced absorption cell, OBPF: optical bandpass filter, PID controller: proportional-integral-derivative controller, CS: current source.
. Figure 2
Fig. 2 Schematic of frequency control and measurements. OFC: optical frequency comb, λ/2: half-wave plate, LPF: electric lowpass filter, GPS: global position system, ECLD: external-cavity laser diode, BPF: electric bandpass filter, PI controller: proportional-integral controller.
illustrates a schematic of frequency control and measurements.

2.1 Spectrometer

The idler frequency is stabilized to one of the longitudinal mode of the CEAC by the Pound-Drever-Hall (PDH) method. The signal wave is phase-modulated by an electro-optic modulator (EOM) at 10 MHz, and the idler frequency is accordingly modulated at the same frequency. The idler wave reflected from the CEAC is detected by another InSb detector. The detected signal is demodulated by a double-balanced mixer to generate an error signal. The slow component of the error signal is fed back to a PZT driving a grating, and the fast component is fed back to injection current of the ECLD.

To stabilize the longitudinal-mode frequency of the CEAC to the saturated absorption line, the cavity length is modulated by applying a 3-kHz sinusoidal voltage to the PZT2 of the CEAC. The idler frequency tightly follows the modulation because of the 250-kHz servo bandwidth of the PDH method. The detected transmission signal is demodulated at 9 kHz (3f detection) by a lock-in amplifier, and the error signal is fed back to the PZT1 of the CEAC through a proportional-integral-derivative (PID) controller. Part of the detected transmission signal is demodulated at 3 kHz (1f detection) by another lock-in amplifier, and the output is added to the error signal to compensate the offset level of the servo electric circuit.

2.2 Fiber comb

The home-built fiber comb is similar to that in References [34

34. H. Inaba, Y. Daimon, F. L. Hong, A. Onae, K. Minoshima, T. R. Schibli, H. Matsumoto, M. Hirano, T. Okuno, M. Onishi, and M. Nakazawa, “Long-term measurement of optical frequencies using a simple, robust and low-noise fiber based frequency comb,” Opt. Express 14(12), 5223–5231 (2006). [CrossRef] [PubMed]

and 37

37. Y. Nakajima, H. Inaba, F. L. Hong, A. Onae, K. Minoshima, T. Kobayashi, M. Nakazawa, and H. Matsumoto, “Optimized amplification of femtosecond optical pulses by dispersion management for octave-spanning optical frequency comb generation,” Opt. Commun. 281(17), 4484–4487 (2008). [CrossRef]

]. It oscillates at 1.558 μm with a repetition rate (frep) of about 65 MHz, a spectral width of 36 nm, and an average power of a few milliwatts. It has several output ports, and three of them are used in the DFG frequency measurement. The first and second ports individually deliver 1% and 25% of the oscillator’s output power. The output of the first port is used for monitoring the oscillation conditions and that of the second port is used for generating the beat note with the signal wave. The third port is connected with a fiber amplifier and a highly nonlinear fiber to broaden the spectrum. The output is used to provide the beat note with the 1.06-μm pump wave.

The output of the first port is received by an InGaAs PIN photodiode, and the detected repetition rate is phase-locked to a frequency synthesizer referenced to a rubidium atomic clock linked to the TAI using GPS signals. The nominal Allan variance of the atomic clock is better than 3 × 10−11 over 1 s, 3 × 10−12 over 1 hour, and 1 × 10−13 over 1 day at worst. The repetition rate is always monitored by a frequency counter referenced to the atomic clock. The offset and the standard deviation of the readout are less than 0.6 mHz for the gate time of 1 s, which is limited by the counter’s resolution and corresponds to 9 × 10−12 relative to the repetition rate.

2.3 Frequency control and measurements

Frequencies of methane transitions are measured as follows. While the frequency of the pump wave is offset-locked to a certain mode of the fiber comb, that of the signal wave is controlled so that the idler wave coincides with the center of the saturated absorption line. Then the frequency of the signal wave is measured with a fiber comb. To this end, one hundredth of the Nd:YAG laser output is, as shown in Fig. 2, extracted by a fiber coupler and overlapped by a beam splitter with the comb output from the fourth port whose spectrum is broadened. The overlapped beam passes through an optical bandpass filter and a grating, and is received by another InGaAs PIN photodiode. The resultant beat note of the signed frequency fbeat1.06μm has a signal-to-noise ratio of about 30 dB and passes through some electronic filters and an electronic amplifier, and is sent to a spectrum analyzer, a frequency counter, and a frequency stabilizing circuit, in which the beat frequency is divided by 512 and mixed by a double balanced mixer with the output of another frequency synthesizer of 41.8 kHz referenced to the atomic clock to generate an error signal. It is fed back to a PZT exerting stress on an optical cavity of the Nd:YAG laser through a proportional-integration (PI) circuit. When this servo-loop is closed, the Allan deviation of the beat frequency fbeat1.06μm reduces less than 1 Hz for a gate time of 1 s.

One tenth of the ECLD output is overlapped with the comb output from the second port by two fiber couplers. The overlapped beam passes through a grating and is received by another InGaAs PIN photodiode. The resultant beat note of the signed frequency fbeat1.55μm has a signal-to-noise ratio of about 40 dB and is monitored by another spectrum analyzer and another frequency counter through some electric filters and amplifiers.

Frequencies measurements are carried out using the following procedures. First, we determine the sign of fbeat1.06μm by varying the repetition rate slightly. Second, we coarsely tune the signal frequencies so that the idler frequency is close to the transition frequency to be measured and observe a saturated absorption line while the longitudinal-mode frequency of the CEAC is swept by applying a triangle voltage to the PZT1 and the idler frequency follows it through the servo-loop. We then stabilize the longitudinal-mode frequency of the CEAC to the center of the saturated absorption line. The absolute value and the sign of fbeat1.55μm is set within the range of 5 to 25 MHz and determined by varying the repetition rate. The absolute values of frep, fbeat1.55μm, and fbeat1.06μm are simultaneously recorded with three frequency counters at a gate time of 1 s. The recorded data are acquired and averaged for 200 times per measurement. We carried out at least two measurements for each transition on different days to verify the reproducibility. Finally, a difference in the mode number of the fiber comb is calculated from data of HITRAN 2008 [12

12. L. S. Rothman, I. E. Gordon, A. Barbe, D. Chris Benner, P. E. Bernath, M. Birk, V. Boudon, L. R. Brown, A. Campargue, J. P. Champion, K. Chance, L. H. Coudert, V. Dana, V. M. Devi, S. Fally, J.-M. Flaud, R. R. Gamache, A. Goldman, D. Jacquemart, I. Kleiner, N. Lacome, W. J. Lafferty, J.-Y. Mandin, S. T. Massie, S. N. Mikhailenko, C. E. Miller, N. Moazzen-Ahmadi, O. V. Naumenko, A. V. Nikitin, J. Orphal, V. I. Perevalov, A. Perrin, A. Predoi-Cross, C. P. Rinsland, M. Rotger, M. Simeckova, M. A. H. Smith, K. Sung, S. A. Tashukun, J. Tennyson, R. A. Toth, A. C. Vandaele, and J. Vander Auwera, “The HITRAN 2008 molecular spectroscopic database,” J. Quant. Spectrosc. Radiat. Transf. 110(9-10), 533–572 (2009). [CrossRef]

], which is based mainly on Doppler-limited FT-IR spectroscopy and includes theoretical extrapolations. Therefore, the determined frequency may deviate from the correct value by integral multiple of frep. However, the transitions we report here were indeed observed in FT-IR spectroscopy, and the uncertainties in the measured wavenumbers are expected less than 20 MHz at worst. The value is smaller than a half of the repetition rate of 65 MHz, and thereby any miscount of the mode difference does not likely occur.

Even though Fig. 2 does not include any parts associated with the carrier-envelope offset frequency, a part of the output of the fiber comb enters an f-2f interferometer, and resultant beat notes are always monitored with a spectrum analyzer and a frequency counter. The beat notes have a rather large linewidth of 100 kHz because the carrier-envelope offset frequency is not servo-controlled in the present measurement. However, it does not increase the uncertainty in the difference frequency averaged over long time.

3. Results and discussion

Figure 3
Fig. 3 Observed spectrum of the Q(6) F2(1) and Q(7) A2.
plots the recorded sub-Doppler resolution spectrum of the Q(6) F2(1) and Q(7) A2 lines. They overlap each other in a Doppler-broadened absorption profile, whereas the saturated absorption lines are clearly resolved. The Doppler broadened line typically reduces the transmitted power by 25 to 70% at the line center, while the saturated absorption line is 1 to 20% deep relative to the Doppler broadened line. The horizontal axis of Fig. 3 indicates the voltage applied to the PZT1 of the CEAC, and it is converted to the idler frequency with a conversion factor determined by observing the interval between the 10-MHz sidebands transmitting the empty CEAC. According to the frequency scale, the saturated absorption line is typically 300 kHz (HWHM) wide. The sharp dispersion near the saturated absorption line may cause deviation from the linear relation between the variation of the cavity length and the resonant frequency of the CEAC [38

38. R. L. Barger and J. L. Hall, “Pressure shift and broadening of methane line at 3.39 μ studied by laser-saturated molecular absorption,” Phys. Rev. Lett. 22(1), 4–8 (1969). [CrossRef]

]. To evaluate the dispersion effect, we have recorded a saturated absorption spectrum of the P(7) F2(2) line by sweeping the idler wave frequency referred to the fiber comb. Figure 4
Fig. 4 Observed saturated absorption spectrum of the P(7) F2(2) . The idler wave frequency is referred to the fiber comb.
indicates the recorded spectrum. The measured linewidth is about 300 kHz again, and hence the dispersion effect is not significant in the present spectrum. The spectral resolution is not high enough to resolve the hyperfine structure [1

1. J. L. Hall, C. J. Bordé, and K. Uehara, “Direct optical resolution of the recoil effect using saturated absorption spectroscopy,” Phys. Rev. Lett. 37(20), 1339–1342 (1976). [CrossRef]

]. The linewidth is limited by the following factors. The transit-time broadening is estimated 72 kHz for the beam width of 0.71 mm at the beam waist [39

39. E. V. Baklanov, B. Ya. Dubetskii, V. M. Semibalamut, and E. A. Titov, “Transit width of a nonlinear power resonance in low-pressure gases,” Sov. J. Quantum Electron. 5(11), 1374–1375 (1975). [CrossRef]

], and pressure broadening is about 13 kHz at 0.5 Pa [40

40. A. Pine, “Self-, N2, O2, H2, Ar, and He broadening in the ν3 band Q branch of CH4,” J. Chem. Phys. 97(2), 773–785 (1992). [CrossRef]

]. The Rabi frequency at the antinodes of the standing wave is expected to be 640 kHz for typical experimental conditions [41

41. L. Féjard, J. P. Champion, J. M. Jouvard, L. R. Brown, and A. S. Pine, “The Intensities of Methane in the 3-5 μm Region Revisited,” J. Mol. Spectrosc. 201, 83–94 (2000).

] with an incident idler power of 100 μW, an absorbance of 70% at the center of the Doppler broadened line, and the mirror loss of 0.003, corresponding to a mirror efficiency of 70%. Considering that the power broadening is some average over the nodes and the antinodes, the measured linewidth is reasonable.

The selection rule for the intense ν3 band transitions does not allow us to determine any energy difference between the rotational levels in the vibrational ground state. The present spectrometer is, however, so sensitive that the two weak transitions are, as listed in Table 1, frequency-measured with an uncertainty of a few kilohertz. As a result, the energy differences between the 77 F2(2) and 66 F2(1) components and between the 77 A2 and 66 A2 components are accurately determined. Even though methane is a non-polar molecule, rotation- and vibration-induced permanent dipole moments cause rotational transitions, and microwave spectroscopy was carried out for the vibrational ground and v3 = 1 states [44

44. M. Takami, K. Uehara, and K. Shimoda, “Rotational transitions of CH4 in the v3 = 1 excited state observed by an infrared-microwave double resonance method,” Jpn. J. Appl. Phys. 12(6), 924–925 (1973). [CrossRef]

47

47. C. J. Pursell and D. P. Weliky, “Pure rotational transitions in the v3 state of methane,” J. Mol. Spectrosc. 153(1-2), 303–306 (1992). [CrossRef]

]. However, only a few transitions were observed, and the accuracy was 10 kHz at best.

Table 1 does not represent the entire performance of the spectrometer. The low frequency limit of Table 1 can be extended up to the P(10) transition within the tunable range of the PPLN used. The sensitivity of the spectrometer also enables us to measure frequencies of the Q branch transitions with a rotational quantum number exceeding 7. Furthermore, the introduction of another PPLN covering the shorter frequency range and an L-band (1.565 to 1.625 μm) fiber amplifier will extend the tunable range of the spectrometer over the R-branch transitions. A more complete list of the transition frequencies will be published in a separate paper.

4. Summary

This article is the first report of precise transition frequency measurement using a highly sensitive and widely tunable 3.4-μm spectrometer. We have determined absolute frequencies of 56 rotation-vibration transitions of the ν3 band of CH4 from 88.2 to 90.5 THz with a typical uncertainty of 2 kHz. The combination of a spectrometer and a fiber comb will open a new era of highly accurate molecular spectroscopy.

Acknowledgments

The authors express their gratitude to SENTAN, Japan Science and Technology Agency and the Photon Frontier Network Program of a Grant-in Aid from the Ministry of Education Culture, Sports, Science and Technology, Japan for financial support.

References and links

1.

J. L. Hall, C. J. Bordé, and K. Uehara, “Direct optical resolution of the recoil effect using saturated absorption spectroscopy,” Phys. Rev. Lett. 37(20), 1339–1342 (1976). [CrossRef]

2.

C. Daussy, T. Marrel, A. Amy-Klein, C. T. Nguyen, C. J. Bordé, and C. Chardonnet, “Limit on the parity nonconserving energy difference between the enantiomers of a chiral molecule by laser spectroscopy,” Phys. Rev. Lett. 83(8), 1554–1557 (1999). [CrossRef]

3.

M. Quack, J. Stohner, and M. Willeke, “High-resolution spectroscopic studies and theory of parity violation in chiral molecules,” Annu. Rev. Phys. Chem. 59(1), 741–769 (2008). [CrossRef] [PubMed]

4.

B. Darquié, C. Stoeffler, A. Shelkovnikov, C. Daussy, A. Amy-Klein, C. Chardonnet, S. Zrig, L. Guy, J. Crassous, P. Soulard, P. Asselin, T. R. Huet, P. Schwerdtfeger, R. Bast, and T. Saue, “Progress toward the first observation of parity violation in chiral molecules by high-resolution laser spectroscopy,” Chirality 22(10), 870–884 (2010). [CrossRef] [PubMed]

5.

C. Daussy, M. Guinet, A. Amy-Klein, K. Djerroud, Y. Hermier, S. Briaudeau, ChJ. Bordé, and C. Chardonnet, “Direct determination of the Boltzmann constant by an optical method,” Phys. Rev. Lett. 98(25), 250801 (2007). [CrossRef] [PubMed]

6.

G. Casa, A. Castrillo, G. Galzerano, R. Wehr, A. Merlone, D. Di Serafino, P. Laporta, and L. Gianfrani, “Primary gas thermometry by means of laser-absorption spectroscopy: determination of the Boltzmann constant,” Phys. Rev. Lett. 100(20), 200801 (2008). [CrossRef] [PubMed]

7.

P. Jensen and P. R. Bunker, eds., Computational molecular spectroscopy, (John-Wiley and Sons Inc., New York, 2000).

8.

G. Guelachvili and K. Narahari Rao, Handbook of Infrared Standards (Academic, Orlando, Fla., 1986). G. Guelachvili and K. Narahari Rao, Handbook of Infrared Standards II (Academic, Orlando, Fla., 1993).

9.

T. J. Quinn, “Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001),” Metrologia 40(2), 103–133 (2003). [CrossRef]

10.

S. Svanberg, Atomic and molecular spectroscopy: Basic aspects and practical applications, 4th edition (Springer Verlag, Berlin, 2004).

11.

J. Tennyson, Astronomical spectroscopy: An introduction to the atomic and molecular physics of astronomical spectra, (World Scientific Publishing Co. Inc., Singapore, 2010).

12.

L. S. Rothman, I. E. Gordon, A. Barbe, D. Chris Benner, P. E. Bernath, M. Birk, V. Boudon, L. R. Brown, A. Campargue, J. P. Champion, K. Chance, L. H. Coudert, V. Dana, V. M. Devi, S. Fally, J.-M. Flaud, R. R. Gamache, A. Goldman, D. Jacquemart, I. Kleiner, N. Lacome, W. J. Lafferty, J.-Y. Mandin, S. T. Massie, S. N. Mikhailenko, C. E. Miller, N. Moazzen-Ahmadi, O. V. Naumenko, A. V. Nikitin, J. Orphal, V. I. Perevalov, A. Perrin, A. Predoi-Cross, C. P. Rinsland, M. Rotger, M. Simeckova, M. A. H. Smith, K. Sung, S. A. Tashukun, J. Tennyson, R. A. Toth, A. C. Vandaele, and J. Vander Auwera, “The HITRAN 2008 molecular spectroscopic database,” J. Quant. Spectrosc. Radiat. Transf. 110(9-10), 533–572 (2009). [CrossRef]

13.

N. Jacquinet-Husson, N. A. Scott, A. Chédin, L. Crépeau, R. Armante, V. Capelle, J. Orphal, A. Coustenis, C. Boonne, N. Poulet-Crovisier, A. Barbe, M. Birk, L. R. Brown, C. Camy-Peyret, C. Claveau, K. Chance, N. Christidis, C. Clerbaux, P. F. Coheur, V. Dana, L. Daumont, M. R. De Backer-Barilly, G. Di Lonardo, J. M. Flaud, A. Goldman, A. Hamdouni, M. Hess, M. D. Hurley, D. Jacquemart, I. Kleiner, P. Köpke, J. Y. Mandin, S. Massie, S. Mikhailenko, V. Nemtchinov, A. Nikitin, D. Newnham, A. Perrin, V. I. Perevalov, S. Pinnock, L. Régalia-Jarlot, C. P. Rinsland, A. Rublev, F. Schreier, L. Schult, K. M. Smith, S. A. Tashkun, J. L. Teffo, R. A. Toth, V. G. Tyuterev, J. Vander Auwera, P. Varanasi, and G. Wagner, “The GEISA spectroscopic database: Current and future archive for Earth and planetary atmosphere studies,” J. Quant. Spectrosc. Radiat. Transf. 109(6), 1043–1059 (2008). [CrossRef]

14.

J. L. Hall and J. A. Magyar, “High resolution saturated absorption studies of methane and some methyl-halides,” in High-Resolution Laser Spectroscopy, K. Shimoda ed. (Springer-Verlag, Berlin, 1976).

15.

A. Amy-Klein, H. Vigué, and C. Chardonnet, “Absolute frequency measurement of 12CO2 laser lines with a femtosecond laser comb and new determination of the 12CO2 molecular constants and frequency grid,” J. Mol. Spectrosc. 228(1), 206–212 (2004). [CrossRef]

16.

A. G. Maki and J. S. Wells, “New wavenumber calibration tables from heterodyne frequency measurements,” J. Res. Natl. Inst. Stand. Technol. 97, 409–470 (1992).

17.

T. George, W. Urban, and A. Le Floch, “Improved mass-independent Dunham parameters for the ground state of CO and calibration frequencies for the fundamental band,” J. Mol. Spectrosc. 165(2), 500–505 (1994). [CrossRef]

18.

G. Magerl, J. M. Frey, W. A. Kreiner, and T. Oka, “Inverse Lamb dip spectroscopy using microwave modulation sidebands of CO2 laser lines,” Appl. Phys. Lett. 42(8), 656–658 (1983). [CrossRef]

19.

B. Meyer, S. Saupe, M. H. Wappelhorst, T. George, F. Kühnemann, M. Schneider, M. Havenith, W. Urban, and J. Legrand, “CO laser side-band spectrometer: Sub-Doppler heterodyne frequency measurements around 5 μm,” Appl. Phys. B 61, 169–173 (1995). [CrossRef]

20.

J. T. Remillard, D. Uy, W. H. Weber, F. Capasso, C. Gmachl, A. L. Hutchinson, D. Sivco, J. Baillargeon, and A. Y. Cho, “Sub-Doppler resolution limited Lamb-dip spectroscopy of NO with a quantum cascade distributed feedback laser,” Opt. Express 7(7), 243–248 (2000). [CrossRef] [PubMed]

21.

E. V. Kovalchuk, D. Dekorsy, A. I. Lvovsky, C. Braxmaier, J. Mlynek, A. Peters, and S. Schiller, “High-resolution Doppler-free molecular spectroscopy with a continuous-wave optical parametric oscillator,” Opt. Lett. 26(18), 1430–1432 (2001). [CrossRef] [PubMed]

22.

O. Tadanaga, T. Yanagawa, Y. Nishida, H. Miyazawa, K. Magari, M. Asobe, and H. Suzuki, “Efficient 3-μm difference frequency generation using direct-bonded quasi-phase-matched LiNbO3 ridge waveguides,” Appl. Phys. Lett. 88(6), 061101 (2006). [CrossRef]

23.

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis,” Science 288(5466), 635–639 (2000). [CrossRef] [PubMed]

24.

T. Yasui, Y. Kabetani, E. Saneyoshi, S. Yokoyama, and T. Araki, “Terahertz frequency comb by multifrequency-heterodyning photoconductive detection for high-accuracy, high-resolution terahertz spectroscopy,” Appl. Phys. Lett. 88(24), 241104 (2006). [CrossRef]

25.

T. J. Pinkert, D. Z. Kandula, C. Gohle, I. Barmes, J. Morgenweg, and K. S. E. Eikema, “Widely tunable extreme UV frequency comb generation,” Opt. Lett. 36(11), 2026–2028 (2011). [CrossRef] [PubMed]

26.

D. Mazzotti, P. Cancio, A. Castrillo, I. Galli, G. Giusfredi, and P. De Natale, “A comb-referenced difference-frequency spectrometer for cavity ring-down spectroscopy in the 4.5 μm region,” J. Opt. A, Pure Appl. Opt. 8(7), S490–S493 (2006). [CrossRef]

27.

P. Malara, P. Maddaloni, G. Gagliardi, and P. De Natale, “Absolute measurement of molecular transitions by a direct link to a comb generated around 3 μm,” Opt. Express 16(11), 8242–8249 (2008). [CrossRef] [PubMed]

28.

P. Maddaloni, P. Malara, E. De Tommasi, M. De Rosa, I. Ricciardi, G. Gagliardi, F. Tamassia, G. Di Lonardo, and P. De Natale, “Absolute measurement of the S(0) and S(1) lines in the electric quadrupole fundamental band of D2 around 3μm,” J. Chem. Phys. 133(15), 154317 (2010). [CrossRef] [PubMed]

29.

D. Mazzotti, P. Cancio, G. Giusfredi, P. De Natale, and M. Prevedelli, “Frequency-comb-based absolute frequency measurements in the mid-infrared with a difference-frequency spectrometer,” Opt. Lett. 30(9), 997–999 (2005). [CrossRef] [PubMed]

30.

K. Takahata, T. Kobayashi, H. Sasada, Y. Nakajima, H. Inaba, and F. L. Hong, “The absolute frequency measurement of sub-Doppler molecular lines using a 3.4-μm difference-frequency-generation spectrometer and a fiber-based frequency comb,” Phys. Rev. A 80(3), 032518 (2009). [CrossRef]

31.

G. Giusfredi, S. Bartalini, S. Borri, P. Cancio, I. Galli, D. Mazzotti, and P. De Natale, “Saturated-absorption cavity ring-down spectroscopy,” Phys. Rev. Lett. 104(11), 110801 (2010). [CrossRef] [PubMed]

32.

M. Abe, K. Takahata, and H. Sasada, “Sub-Doppler resolution 3.4 microm spectrometer with an efficient difference-frequency-generation source,” Opt. Lett. 34(11), 1744–1746 (2009). [CrossRef] [PubMed]

33.

T. R. Schibli, K. Minoshima, F. L. Hong, H. Inaba, A. Onae, H. Matsumoto, I. Hartl, and M. E. Fermann, “Frequency metrology with a turnkey all-fiber system,” Opt. Lett. 29(21), 2467–2469 (2004). [CrossRef] [PubMed]

34.

H. Inaba, Y. Daimon, F. L. Hong, A. Onae, K. Minoshima, T. R. Schibli, H. Matsumoto, M. Hirano, T. Okuno, M. Onishi, and M. Nakazawa, “Long-term measurement of optical frequencies using a simple, robust and low-noise fiber based frequency comb,” Opt. Express 14(12), 5223–5231 (2006). [CrossRef] [PubMed]

35.

J. Ye and J. L. Hall, “Absorption detection at the quantum limit: Probing high-finesse cavities with modulation techniques,” in Cavity-enhanced spectroscopy, Experimental methods in the physical sciences vol. 40, R. D. van Zee and J. P. Looney ed. (Academic Press, San Diego, 2002).

36.

S. Okubo, H. Nakayama, and H. Sasada, “Hyperfine-resolved 3.4-μm spectroscopy of CH3I with a widely tunable frequency generation source and a cavity-enhanced cell: A case study of a local Coriolis interaction between the v1 = 1 and (v2, v6l) = (1, 22) states,” Phys. Rev. A 83(1), 012505 (2011). [CrossRef]

37.

Y. Nakajima, H. Inaba, F. L. Hong, A. Onae, K. Minoshima, T. Kobayashi, M. Nakazawa, and H. Matsumoto, “Optimized amplification of femtosecond optical pulses by dispersion management for octave-spanning optical frequency comb generation,” Opt. Commun. 281(17), 4484–4487 (2008). [CrossRef]

38.

R. L. Barger and J. L. Hall, “Pressure shift and broadening of methane line at 3.39 μ studied by laser-saturated molecular absorption,” Phys. Rev. Lett. 22(1), 4–8 (1969). [CrossRef]

39.

E. V. Baklanov, B. Ya. Dubetskii, V. M. Semibalamut, and E. A. Titov, “Transit width of a nonlinear power resonance in low-pressure gases,” Sov. J. Quantum Electron. 5(11), 1374–1375 (1975). [CrossRef]

40.

A. Pine, “Self-, N2, O2, H2, Ar, and He broadening in the ν3 band Q branch of CH4,” J. Chem. Phys. 97(2), 773–785 (1992). [CrossRef]

41.

L. Féjard, J. P. Champion, J. M. Jouvard, L. R. Brown, and A. S. Pine, “The Intensities of Methane in the 3-5 μm Region Revisited,” J. Mol. Spectrosc. 201, 83–94 (2000).

42.

P. S. Ering, D. A. Tyurikov, G. Kramer, and B. Lipphardt, “Measurement of the absolute frequency of the methane E-line at 88 THz,” Opt. Commun. 151(4-6), 229–234 (1998). [CrossRef]

43.

J. L. Hall and C. J. Bordé, “Shift and broadening of saturated absorption resonances due to curvature of the laser wave front,” Appl. Phys. Lett. 29(12), 788 (1976). [CrossRef]

44.

M. Takami, K. Uehara, and K. Shimoda, “Rotational transitions of CH4 in the v3 = 1 excited state observed by an infrared-microwave double resonance method,” Jpn. J. Appl. Phys. 12(6), 924–925 (1973). [CrossRef]

45.

R. F. Curl Jr., “Infrared-radio frequency double resonance observations of pure rotational Q-branch transitions of methane,” J. Mol. Spectrosc. 48(1), 165–173 (1973). [CrossRef]

46.

R. F. Curl, T. Oka, and D. S. Smith, “The observation of a pure rotational Q-branch transition of methane by infrared-radio frequency double resonance,” J. Mol. Spectrosc. 46(3), 518–520 (1973). [CrossRef]

47.

C. J. Pursell and D. P. Weliky, “Pure rotational transitions in the v3 state of methane,” J. Mol. Spectrosc. 153(1-2), 303–306 (1992). [CrossRef]

OCIS Codes
(120.3940) Instrumentation, measurement, and metrology : Metrology
(300.6320) Spectroscopy : Spectroscopy, high-resolution
(300.6390) Spectroscopy : Spectroscopy, molecular
(300.6460) Spectroscopy : Spectroscopy, saturation

ToC Category:
Spectroscopy

History
Original Manuscript: September 2, 2011
Revised Manuscript: October 28, 2011
Manuscript Accepted: October 31, 2011
Published: November 9, 2011

Citation
Sho Okubo, Hirotaka Nakayama, Kana Iwakuni, Hajime Inaba, and Hiroyuki Sasada, "Absolute frequency list of the ν3-band transitions of methane at a relative uncertainty level of 10−11," Opt. Express 19, 23878-23888 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-24-23878


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. J. L. Hall, C. J. Bordé, and K. Uehara, “Direct optical resolution of the recoil effect using saturated absorption spectroscopy,” Phys. Rev. Lett. 37(20), 1339–1342 (1976). [CrossRef]
  2. C. Daussy, T. Marrel, A. Amy-Klein, C. T. Nguyen, C. J. Bordé, and C. Chardonnet, “Limit on the parity nonconserving energy difference between the enantiomers of a chiral molecule by laser spectroscopy,” Phys. Rev. Lett. 83(8), 1554–1557 (1999). [CrossRef]
  3. M. Quack, J. Stohner, and M. Willeke, “High-resolution spectroscopic studies and theory of parity violation in chiral molecules,” Annu. Rev. Phys. Chem. 59(1), 741–769 (2008). [CrossRef] [PubMed]
  4. B. Darquié, C. Stoeffler, A. Shelkovnikov, C. Daussy, A. Amy-Klein, C. Chardonnet, S. Zrig, L. Guy, J. Crassous, P. Soulard, P. Asselin, T. R. Huet, P. Schwerdtfeger, R. Bast, and T. Saue, “Progress toward the first observation of parity violation in chiral molecules by high-resolution laser spectroscopy,” Chirality 22(10), 870–884 (2010). [CrossRef] [PubMed]
  5. C. Daussy, M. Guinet, A. Amy-Klein, K. Djerroud, Y. Hermier, S. Briaudeau, ChJ. Bordé, and C. Chardonnet, “Direct determination of the Boltzmann constant by an optical method,” Phys. Rev. Lett. 98(25), 250801 (2007). [CrossRef] [PubMed]
  6. G. Casa, A. Castrillo, G. Galzerano, R. Wehr, A. Merlone, D. Di Serafino, P. Laporta, and L. Gianfrani, “Primary gas thermometry by means of laser-absorption spectroscopy: determination of the Boltzmann constant,” Phys. Rev. Lett. 100(20), 200801 (2008). [CrossRef] [PubMed]
  7. P. Jensen and P. R. Bunker, eds., Computational molecular spectroscopy, (John-Wiley and Sons Inc., New York, 2000).
  8. G. Guelachvili and K. Narahari Rao, Handbook of Infrared Standards (Academic, Orlando, Fla., 1986). G. Guelachvili and K. Narahari Rao, Handbook of Infrared Standards II (Academic, Orlando, Fla., 1993).
  9. T. J. Quinn, “Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001),” Metrologia 40(2), 103–133 (2003). [CrossRef]
  10. S. Svanberg, Atomic and molecular spectroscopy: Basic aspects and practical applications, 4th edition (Springer Verlag, Berlin, 2004).
  11. J. Tennyson, Astronomical spectroscopy: An introduction to the atomic and molecular physics of astronomical spectra, (World Scientific Publishing Co. Inc., Singapore, 2010).
  12. L. S. Rothman, I. E. Gordon, A. Barbe, D. Chris Benner, P. E. Bernath, M. Birk, V. Boudon, L. R. Brown, A. Campargue, J. P. Champion, K. Chance, L. H. Coudert, V. Dana, V. M. Devi, S. Fally, J.-M. Flaud, R. R. Gamache, A. Goldman, D. Jacquemart, I. Kleiner, N. Lacome, W. J. Lafferty, J.-Y. Mandin, S. T. Massie, S. N. Mikhailenko, C. E. Miller, N. Moazzen-Ahmadi, O. V. Naumenko, A. V. Nikitin, J. Orphal, V. I. Perevalov, A. Perrin, A. Predoi-Cross, C. P. Rinsland, M. Rotger, M. Simeckova, M. A. H. Smith, K. Sung, S. A. Tashukun, J. Tennyson, R. A. Toth, A. C. Vandaele, and J. Vander Auwera, “The HITRAN 2008 molecular spectroscopic database,” J. Quant. Spectrosc. Radiat. Transf. 110(9-10), 533–572 (2009). [CrossRef]
  13. N. Jacquinet-Husson, N. A. Scott, A. Chédin, L. Crépeau, R. Armante, V. Capelle, J. Orphal, A. Coustenis, C. Boonne, N. Poulet-Crovisier, A. Barbe, M. Birk, L. R. Brown, C. Camy-Peyret, C. Claveau, K. Chance, N. Christidis, C. Clerbaux, P. F. Coheur, V. Dana, L. Daumont, M. R. De Backer-Barilly, G. Di Lonardo, J. M. Flaud, A. Goldman, A. Hamdouni, M. Hess, M. D. Hurley, D. Jacquemart, I. Kleiner, P. Köpke, J. Y. Mandin, S. Massie, S. Mikhailenko, V. Nemtchinov, A. Nikitin, D. Newnham, A. Perrin, V. I. Perevalov, S. Pinnock, L. Régalia-Jarlot, C. P. Rinsland, A. Rublev, F. Schreier, L. Schult, K. M. Smith, S. A. Tashkun, J. L. Teffo, R. A. Toth, V. G. Tyuterev, J. Vander Auwera, P. Varanasi, and G. Wagner, “The GEISA spectroscopic database: Current and future archive for Earth and planetary atmosphere studies,” J. Quant. Spectrosc. Radiat. Transf. 109(6), 1043–1059 (2008). [CrossRef]
  14. J. L. Hall and J. A. Magyar, “High resolution saturated absorption studies of methane and some methyl-halides,” in High-Resolution Laser Spectroscopy, K. Shimoda ed. (Springer-Verlag, Berlin, 1976).
  15. A. Amy-Klein, H. Vigué, and C. Chardonnet, “Absolute frequency measurement of 12CO2 laser lines with a femtosecond laser comb and new determination of the 12CO2 molecular constants and frequency grid,” J. Mol. Spectrosc. 228(1), 206–212 (2004). [CrossRef]
  16. A. G. Maki and J. S. Wells, “New wavenumber calibration tables from heterodyne frequency measurements,” J. Res. Natl. Inst. Stand. Technol. 97, 409–470 (1992).
  17. T. George, W. Urban, and A. Le Floch, “Improved mass-independent Dunham parameters for the ground state of CO and calibration frequencies for the fundamental band,” J. Mol. Spectrosc. 165(2), 500–505 (1994). [CrossRef]
  18. G. Magerl, J. M. Frey, W. A. Kreiner, and T. Oka, “Inverse Lamb dip spectroscopy using microwave modulation sidebands of CO2 laser lines,” Appl. Phys. Lett. 42(8), 656–658 (1983). [CrossRef]
  19. B. Meyer, S. Saupe, M. H. Wappelhorst, T. George, F. Kühnemann, M. Schneider, M. Havenith, W. Urban, and J. Legrand, “CO laser side-band spectrometer: Sub-Doppler heterodyne frequency measurements around 5 μm,” Appl. Phys. B 61, 169–173 (1995). [CrossRef]
  20. J. T. Remillard, D. Uy, W. H. Weber, F. Capasso, C. Gmachl, A. L. Hutchinson, D. Sivco, J. Baillargeon, and A. Y. Cho, “Sub-Doppler resolution limited Lamb-dip spectroscopy of NO with a quantum cascade distributed feedback laser,” Opt. Express 7(7), 243–248 (2000). [CrossRef] [PubMed]
  21. E. V. Kovalchuk, D. Dekorsy, A. I. Lvovsky, C. Braxmaier, J. Mlynek, A. Peters, and S. Schiller, “High-resolution Doppler-free molecular spectroscopy with a continuous-wave optical parametric oscillator,” Opt. Lett. 26(18), 1430–1432 (2001). [CrossRef] [PubMed]
  22. O. Tadanaga, T. Yanagawa, Y. Nishida, H. Miyazawa, K. Magari, M. Asobe, and H. Suzuki, “Efficient 3-μm difference frequency generation using direct-bonded quasi-phase-matched LiNbO3 ridge waveguides,” Appl. Phys. Lett. 88(6), 061101 (2006). [CrossRef]
  23. D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis,” Science 288(5466), 635–639 (2000). [CrossRef] [PubMed]
  24. T. Yasui, Y. Kabetani, E. Saneyoshi, S. Yokoyama, and T. Araki, “Terahertz frequency comb by multifrequency-heterodyning photoconductive detection for high-accuracy, high-resolution terahertz spectroscopy,” Appl. Phys. Lett. 88(24), 241104 (2006). [CrossRef]
  25. T. J. Pinkert, D. Z. Kandula, C. Gohle, I. Barmes, J. Morgenweg, and K. S. E. Eikema, “Widely tunable extreme UV frequency comb generation,” Opt. Lett. 36(11), 2026–2028 (2011). [CrossRef] [PubMed]
  26. D. Mazzotti, P. Cancio, A. Castrillo, I. Galli, G. Giusfredi, and P. De Natale, “A comb-referenced difference-frequency spectrometer for cavity ring-down spectroscopy in the 4.5 μm region,” J. Opt. A, Pure Appl. Opt. 8(7), S490–S493 (2006). [CrossRef]
  27. P. Malara, P. Maddaloni, G. Gagliardi, and P. De Natale, “Absolute measurement of molecular transitions by a direct link to a comb generated around 3 μm,” Opt. Express 16(11), 8242–8249 (2008). [CrossRef] [PubMed]
  28. P. Maddaloni, P. Malara, E. De Tommasi, M. De Rosa, I. Ricciardi, G. Gagliardi, F. Tamassia, G. Di Lonardo, and P. De Natale, “Absolute measurement of the S(0) and S(1) lines in the electric quadrupole fundamental band of D2 around 3μm,” J. Chem. Phys. 133(15), 154317 (2010). [CrossRef] [PubMed]
  29. D. Mazzotti, P. Cancio, G. Giusfredi, P. De Natale, and M. Prevedelli, “Frequency-comb-based absolute frequency measurements in the mid-infrared with a difference-frequency spectrometer,” Opt. Lett. 30(9), 997–999 (2005). [CrossRef] [PubMed]
  30. K. Takahata, T. Kobayashi, H. Sasada, Y. Nakajima, H. Inaba, and F. L. Hong, “The absolute frequency measurement of sub-Doppler molecular lines using a 3.4-μm difference-frequency-generation spectrometer and a fiber-based frequency comb,” Phys. Rev. A 80(3), 032518 (2009). [CrossRef]
  31. G. Giusfredi, S. Bartalini, S. Borri, P. Cancio, I. Galli, D. Mazzotti, and P. De Natale, “Saturated-absorption cavity ring-down spectroscopy,” Phys. Rev. Lett. 104(11), 110801 (2010). [CrossRef] [PubMed]
  32. M. Abe, K. Takahata, and H. Sasada, “Sub-Doppler resolution 3.4 microm spectrometer with an efficient difference-frequency-generation source,” Opt. Lett. 34(11), 1744–1746 (2009). [CrossRef] [PubMed]
  33. T. R. Schibli, K. Minoshima, F. L. Hong, H. Inaba, A. Onae, H. Matsumoto, I. Hartl, and M. E. Fermann, “Frequency metrology with a turnkey all-fiber system,” Opt. Lett. 29(21), 2467–2469 (2004). [CrossRef] [PubMed]
  34. H. Inaba, Y. Daimon, F. L. Hong, A. Onae, K. Minoshima, T. R. Schibli, H. Matsumoto, M. Hirano, T. Okuno, M. Onishi, and M. Nakazawa, “Long-term measurement of optical frequencies using a simple, robust and low-noise fiber based frequency comb,” Opt. Express 14(12), 5223–5231 (2006). [CrossRef] [PubMed]
  35. J. Ye and J. L. Hall, “Absorption detection at the quantum limit: Probing high-finesse cavities with modulation techniques,” in Cavity-enhanced spectroscopy, Experimental methods in the physical sciences vol. 40, R. D. van Zee and J. P. Looney ed. (Academic Press, San Diego, 2002).
  36. S. Okubo, H. Nakayama, and H. Sasada, “Hyperfine-resolved 3.4-μm spectroscopy of CH3I with a widely tunable frequency generation source and a cavity-enhanced cell: A case study of a local Coriolis interaction between the v1 = 1 and (v2, v6l) = (1, 22) states,” Phys. Rev. A 83(1), 012505 (2011). [CrossRef]
  37. Y. Nakajima, H. Inaba, F. L. Hong, A. Onae, K. Minoshima, T. Kobayashi, M. Nakazawa, and H. Matsumoto, “Optimized amplification of femtosecond optical pulses by dispersion management for octave-spanning optical frequency comb generation,” Opt. Commun. 281(17), 4484–4487 (2008). [CrossRef]
  38. R. L. Barger and J. L. Hall, “Pressure shift and broadening of methane line at 3.39 μ studied by laser-saturated molecular absorption,” Phys. Rev. Lett. 22(1), 4–8 (1969). [CrossRef]
  39. E. V. Baklanov, B. Ya. Dubetskii, V. M. Semibalamut, and E. A. Titov, “Transit width of a nonlinear power resonance in low-pressure gases,” Sov. J. Quantum Electron. 5(11), 1374–1375 (1975). [CrossRef]
  40. A. Pine, “Self-, N2, O2, H2, Ar, and He broadening in the ν3 band Q branch of CH4,” J. Chem. Phys. 97(2), 773–785 (1992). [CrossRef]
  41. L. Féjard, J. P. Champion, J. M. Jouvard, L. R. Brown, and A. S. Pine, “The Intensities of Methane in the 3-5 μm Region Revisited,” J. Mol. Spectrosc. 201, 83–94 (2000).
  42. P. S. Ering, D. A. Tyurikov, G. Kramer, and B. Lipphardt, “Measurement of the absolute frequency of the methane E-line at 88 THz,” Opt. Commun. 151(4-6), 229–234 (1998). [CrossRef]
  43. J. L. Hall and C. J. Bordé, “Shift and broadening of saturated absorption resonances due to curvature of the laser wave front,” Appl. Phys. Lett. 29(12), 788 (1976). [CrossRef]
  44. M. Takami, K. Uehara, and K. Shimoda, “Rotational transitions of CH4 in the v3 = 1 excited state observed by an infrared-microwave double resonance method,” Jpn. J. Appl. Phys. 12(6), 924–925 (1973). [CrossRef]
  45. R. F. Curl., “Infrared-radio frequency double resonance observations of pure rotational Q-branch transitions of methane,” J. Mol. Spectrosc. 48(1), 165–173 (1973). [CrossRef]
  46. R. F. Curl, T. Oka, and D. S. Smith, “The observation of a pure rotational Q-branch transition of methane by infrared-radio frequency double resonance,” J. Mol. Spectrosc. 46(3), 518–520 (1973). [CrossRef]
  47. C. J. Pursell and D. P. Weliky, “Pure rotational transitions in the v3 state of methane,” J. Mol. Spectrosc. 153(1-2), 303–306 (1992). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited