OSA's Digital Library

Optics Express

Optics Express

  • Editor: Michael Duncan
  • Vol. 14, Iss. 11 — May. 29, 2006
  • pp: 4721–4726
« Show journal navigation

Simultaneous multi-wavelength oscillation of Nd laser around 1.3 µm: A potential source for coherent terahertz generation

Ardhendu Saha, Aniruddha Ray, Sourabh Mukhopadhyay, Nandita Sinha, Prasanta Kumar Datta, and Pranab Kumar Dutta  »View Author Affiliations


Optics Express, Vol. 14, Issue 11, pp. 4721-4726 (2006)
http://dx.doi.org/10.1364/OE.14.004721


View Full Text Article

Acrobat PDF (99 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Simultaneous oscillations of 1318.8nm, 1320.0nm, 1332.6nm, 1335.0nm, 1338.2nm and 1339.0nm in a side, pulsed-diode-laser-array pumped Nd:YAG laser is realized for both free running and Q-switched operation. An average power of 1.1W is obtained for an absorbed pump power of 7.1W with an effective optical slope efficiency of 33%. The difference frequency interactions among these wavelengths may be used to generate radiation in the range 0.13–3.43THz. With the two most intense lines at 1318.8nm and 1338.2nm, it is possible to generate coherent radiation at 3.3THz with numerically estimated peak power of 0.21W in a 1.5mm thick GaSe crystal.

© 2006 Optical Society of America

1. Introduction

Research on generation of coherent terahertz radiation has got momentum recently because of its immense applications in biological imaging, spectroscopy, chemical identification and heterodyne radiometry for astrophysics [1

1. B. Ferguson and X. C. Zhang, “Materials for terahertz science and technology,” Nature Materials 1, 26–33 (2002). [CrossRef]

, 2

2. M. Brucherseifer, M. Nagel, P. Haring Bolivar, H. Kurz, A. Bosserhoff, and R. Buttner, “Label-free probing of the binding state of DNA by time-domain terahertz sensing,” Appl. Phys. Lett. 77, 4049–4051, (2000). [CrossRef]

]. Although the terahertz radiation is usually defined for the range of 0.1–10 THz (30µm to 3000µm), but there is a strong demand for the range 1–3 THz. The primary sources for terahertz such as Gunn diode oscillators with multipliers and CO2 laser pumped far-infrared gas lasers [3

3. M. A. Frerking, “Submillimeter source needs for NASA mission,” Proc. SPIE 2145, 222–229 (1994). [CrossRef]

, 4

4. B. D. Guenther, “Terahertz sources,” Proc. SPIE 2145, 120–129 (1994). [CrossRef]

] suffer from efficiency and complexity, barring them for use in some specific applications. But the secondary sources based on mixing of two laser frequencies are very compact and promise to be very efficient [5

5. W. Shei and Y. J. Ding, “Continuously tunable and coherent terahertz radiation by means of phase-matched difference frequency generation in zinc germanium phosphide,” Appl. Phys. Lett. 83, 848–850 (2003). [CrossRef]

, 6

6. T. Taniuchi, S. Okada, and H. Nakanishi, “Widely-tunable THz-wave generation in 2–20THz range from DAST crystal by nonlinear difference frequency mixing,” Electron. Lett. 40, 60–61 (2004). [CrossRef]

]. For this purpose a simultaneous multi-wavelength primary laser source is superior to using two separate lasers, where the phase-locked loop based stabilization is essential. In solid-state lasers, the multi-wavelength operation is possible because the energy levels of active ions split into a number of Stark levels due to the action of crystal field. The rare-earth doped solid-state lasers generally oscillate at one wavelength when there is a wide difference of stimulated emission cross section (σ) such as around 1064nm for Nd:YAG laser. Difficulty in simultaneous cw multi-wavelength operation of rare-earth doped lasers is an issue [7

7. H. Y. Shen, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z.D. Zeng, W. J. Zhang, and Q. J. Ye, “Simultaneous multiple wavelength laser action in various Neodymium host crystals,” IEEE J. Quantum. Electron. 27, 2315–2318 (1991). [CrossRef]

]. But there are some closely spaced transition lines, around 1.3µm with comparable values of σ, which can be employed for terahertz generation by difference frequency mixing. Terahertz generation by difference frequency mixing requires the higher frequency pump to be efficient one, making the multi-wavelength operation of a laser and subsequent mixing of the intense line at higher frequency and one of the weak lines of the lower frequency a possible tunable source for it.

In Nd3+ ion, there exist two efficient transitions in the vicinity of 1.3µm corresponding to 4F3/24I13/2 [8

8. W. Koechner, “Solid-State Laser Engineering,” Springer, 5th Ed., pp. 46–56, 1999.

]. They are R2→X1 & R2→X3 leading to laser radiations around 1318.8nm and 1338.2nm. These energy levels are shown in Fig. 1. There are mainly five other transition lines in the vicinity of 1318 nm and 1338 nm.

Fig. 1. Stark splitting of 4F3/2 and 4I13/2 of Nd3+ion in YAG host

They are 1320.0nm, 1333.8nm, 1335.0nm, 1341.0nm and 1356.4nm corresponding to the transition R2→X2, R1→X1, R1→X2,R2→X4, R1→X4. Due to fast thermalization of the sublevels these transitions strongly compete with each other. Dual wavelength oscillation has been reported using special techniques in Nd:YAG laser at 1064nm and 1318nm [9

9. R. W. Farley and P. D. Dao, “Development of an intracavity-summed multiple-wavelength Nd:YAG laser for a rugged, solid-state sodium lidar system,” Appl. Opt. 34, 4269–4273, (1995). [CrossRef] [PubMed]

], 1319nm and 1338.2nm [10

10. R. Zhou, W. Wen, Z. Cai, X. Ding, P. Wang, and J. Yao, “Efficient stable simultaneous CW dual wavelength diode-end-pumped Nd:YAG laser operating at 1.319 and 1.338 µm,” Chinese Opt. Lett. 3, 597–599, (2005).

] and in Nd:YAlO3 at 1079.5nm and 1341.4nm [11

11. H. Y. Shen, W. X. Lin, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z. D. Zeng, W. J. Zhang, R. F. Wu, and Q. J. Ye, “1079.5- and 1341.4-nm: larger energy from a dual-wavelength Nd:YAlO3 pulsed laser,” Appl. Opt. 32, 5952–5975, (1993). [CrossRef] [PubMed]

]. Recently simultaneous oscillation around 1064nm and 946nm [12

12. Y. Lu, B. Zhang, E. Li, D. Xu, R. Zhou, X. Zhao, F. Ji, T. Zhang, P. Wang, and J. Yao, “High-power simultaneous dual-wavelength emission of an end-pumped Nd:YAG laser using the quasi-three-level and the four-level transition,” Opt. Commun. (2006) (in press). [CrossRef]

13

13. P. X. Li, D. H. Li, C. Y. Li, and Z. G. Zhang, “Simultaneous dual-wavelength continuous wave laser operation at 1.06 µm and 946 nm in Nd:YAG and their frequency doubling,” Opt. Commun. 235, 169–174, (2004). [CrossRef]

] has been reported. Solid-state lasers with simultaneous multi wavelength operation can also be used for medical, military and scientific applications [9

9. R. W. Farley and P. D. Dao, “Development of an intracavity-summed multiple-wavelength Nd:YAG laser for a rugged, solid-state sodium lidar system,” Appl. Opt. 34, 4269–4273, (1995). [CrossRef] [PubMed]

, 11

11. H. Y. Shen, W. X. Lin, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z. D. Zeng, W. J. Zhang, R. F. Wu, and Q. J. Ye, “1079.5- and 1341.4-nm: larger energy from a dual-wavelength Nd:YAlO3 pulsed laser,” Appl. Opt. 32, 5952–5975, (1993). [CrossRef] [PubMed]

]. Reference [10

10. R. Zhou, W. Wen, Z. Cai, X. Ding, P. Wang, and J. Yao, “Efficient stable simultaneous CW dual wavelength diode-end-pumped Nd:YAG laser operating at 1.319 and 1.338 µm,” Chinese Opt. Lett. 3, 597–599, (2005).

] uses end pump geometry to achieve only three wavelengths oscillation simultaneously.

In this article, we report the simultaneous oscillations of 1318.8nm, 1320.0nm, 1332.6nm, 1335.0nm, 1338.2nm and 1339.0nm in a side pulsed-diode-laser-array pumped Nd:YAG laser for both free running and Q-switched operation using a broadband output coupler. An average power of 1.1W was obtained for a quasi-cw absorbed pump power of 7.6W. We also investigate for the first time the difference frequency interactions among these wavelengths of the single laser for possible terahertz generation in the range 0.13–3.43THz.

2. Experiment

Fig. 2. Laser layout: LDA, laser diode array; RM, rear mirror; AOQS, acousto-optic Q-switch; OC, Broadband output coupler; L, Nd:YAG rod; BBO, Beta-Barium Borate crystal

The schematic for multi-wavelength operation of the Nd:YAG laser is shown in Fig. 2. A Nd:YAG rod of length 63mm and diameter of 2mm with Nd3+ doping concentration of 0.6% was used as the gain medium. The central 32mm of the rod was effectively pumped radially by eighteen temperature tuned pulsed laser diode bars emitting at the wavelength of 808nm. The pump pulse duration and the repetition rate could be varied over the range of 50µs–550µs and 50Hz–1kHz respectively. The rear mirror (RM) was concave with radius of curvature 500mm with reflectivity (R) of 99.5% in the wavelength range of 1300nm to 1400nm having a high transmittance (T=93 %) at 1064nm. A broadband flat mirror with the R/T values of 85/15 in the wavelength range of 1300nm to 1400nm was used as output coupler. The cavity length was optimized at 335mm for maximum output power with single transverse mode. The beam diameters at the Nd:YAG rod and output coupler were about 0.9mm and 0.6mm respectively. The Q-switched operation was realized using a fused silica, Brewster-cut acousto-optic modulator driven at 27.2MHz with a modulating signal in the range 1kHz–50kHz.

The wavelengths were detected by a 0.67m long (focal length) monochromator (McPHERSON, USA) with an achieved resolution of 0.2nm. Six different wavelengths were observed and their partial power were measured with the help of a room temperature InGaAs photodiode.

3. Result and Discussion

The partial contribution of the different oscillating wavelengths under free running lasing operation are plotted in Fig. 3. We define the partial contribution (α) as the percentage ratio of the individual power (Pi) of the lines to the total power of all the lines (P=∑Pi), that is the output power.

α=(PiP×100)

We observed a blue shift of the transition lines 1333.8nm and 1341nm by 1.2nm and 2.0nm respectively.

Fig. 3. The partial contribution of the lasing lines in the logarithmic scale
Fig. 4. Average output power versus absorbed pump power (by varying diode current) corresponding to the pump pulse repetition rate of 200 Hz. The red line is the best fit for the data

These shifts may be attributed to the change in temperature of the Nd:YAG crystal [14

14. J. Marling, “1.05–1.44 µm Tunability and Performance of the CW Nd3+ :YAG Laser,” IEEE J. Quantum. Electron. 14, 56–62, (1978). [CrossRef]

]. Repeated measurements were taken to confirm this large shift. Varying the diode current, while keeping the pulse repetition rate unaltered, the laser output power is found to increase linearly (Fig. 4) with the input pump power with an average slope efficiency of about 33 %. The maximum laser power obtained was 1.1W corresponding to the absorbed pump power of 7.6W.

However the output power is not always a linear function of the repetition rate of the pump pulse. The output power was found to increase linearly with the pump pulse repetition rate, varying form 50Hz to 200Hz, as shown in Fig. 5. For the repetition rate above 220Hz, the output power decreases because of the thermal lensing in the Nd:YAG rod. The thermal lensing effect was investigated by monitoring the mode size variation of a He-Ne laser beam on a CCD camera (Gentec Inc,USA) after passing through the Nd:YAG rod under free running condition. The variation of the observed focal length of the rod with the pulse repetition rate (absorbed power) is shown in Fig. 6.

We also obtained intra-cavity sum frequency generation (SFG) and second harmonic generation (SHG) of the lasing wavelengths in a 3mm thick BBO crystal (φ=90° & θ=22.8°).

Fig. 5. Average output power versus pump pulse repetition rate/absorbed pump power
Fig. 6. Variation focal length of thermal lens as a function of absorbed pump power. Input pump power is varied by changing the pump repletion rate.
Fig. 7. Transverse beam profile of the SHG and SFG of Nd:YAG laser
Fig. 8. Q-switch pulse trace for modulation frequency of 10kHz

About 20 different wavelengths (SHG and SFG) were obtained with their power varying from 1mW to about 25mW under free-running condition, indicating the fact that even the lasing transitions with lower gain cross section were strong enough for non-linear optical interactions. These second harmonic wavelengths were also observed for each single Q-switched pulse. All the lasing lines that were simultaneously oscillating in quasi CW mode were also observed in the Q-switched mode of operation. The transverse profile of output beam was investigated by imaging the SHG and the SFG beam on a Si based CCD camera and it was found to be nearly TEM00 (Fig. 7). On Q-switched operation of the multi-wavelength oscillating laser, we obtained pulse width of about 150ns (Fig. 8) for modulator frequency of 10kHz.

Now we investigate the possible generation of terahertz by difference frequency mixing of the oscillating wavelengths from the multi wavelength laser. Difference frequency generation (DFG) offers relative compactness, simplicity for tuning, straightforward alignment, much lower pump intensities and stable THz output. Indeed, unlike Optical parametric oscillator (OPO), DFG does not require a complicated alignment procedure. Let us consider the DFG of the two intense lines, 1318.8nm and 1338.2nm in a GaSe crystal, as an example. The collinear interaction is favourable, as it is easy to separate out the THz signal from the input pump beams by different methods. For GaSe, the phase-matching angle for this range of interaction changes negligibly for a quite large range of pump wavelengths. The effective second order nonlinearity (deff) is about 54pm/V [15

15. W. Shi, Y.J. Ding, N. Fernelius, and K. Vodopyanov, “Efficient, tunable, and coherent 0.18–5.27-THz source based on GaSe crystal,” Opt. Lett. 27, 1454–1456, (2002). [CrossRef]

]. The Q-switched multi-wavelength Nd:YAG laser provides partial peak powers of about 20.8kW and 15.1kW at 1318.8nm and 1338.2nm respectively. For a beam of diameter 0.6mm, the peak intensities (I), incident in the crystal would be 14.75MW/cm2 and 10.7MW/cm2. These values of intensities are well below the optical damage threshold of GaSe. The only hurdle in THz generation using nonlinear optical crystals is the large absorption, limiting the usable crystal length (L) less than 4mm. The signal at 3.3THz (88µm) to be generated by DFG has an absorption coefficient (α) of about 25cm-1, whereas it is only 0.5cm-1 at the pump wavelengths. A conversion efficiency (ηdiff ) of 1.28×10-5 can then be obtained from the following expression [16

16. R. L. Sutherland, “Handbook of nonlinear optics,” Marcel Dekker Inc, 87, (1996).

] for an optimum crystal length of 1.5mm.

ηdiff=ηdiff0 exp[-(αpumppump2diff )L/2],

where,

ηdiff0=8π2deff2L2Ipump1ε0npump1npump2ndiffcλdiff2

and n is the refractive index of the crystal. A peak power of 0.21W corresponding to an average power of 6.3µW at 3.3THz can be obtained from the scheme. The generated THz signal can easily be measured with a Si bolometer. The tunable THz radiation can be obtained by slightly changing the laser cavity design. If a grating is used in the littmann configuration with two mirrors reflecting back the first order of the two desired lines, then we can obtain simultaneous dual wavelength oscillation. This way a combination of any two wavelengths out of the available six wavelengths, can be obtained and their difference frequency can generate coherent THz radiation.

4. Conclusion

We have realized quasi cw lasing operation of a side pulsed-diode-array pumped Nd:YAG laser with simultaneous oscillation of six different lines around 1.3µm with TEM00 transverse mode. Intra-cavity SHG and SFG of oscillating wavelengths indicate that even the lasing transition lines with lower gain cross section such as 1320.0nm, 1332.6nm, 1335.0nm and 1339nm are strong enough to exhibit nonlinear interaction. Q-switched multi-wavelength operation is achieved with an acousto-optic Q-switch providing a peak power of 36kW. The laser is capable of generating useful coherent THz radiation in the range 0.13THz–3.43THz with peak power of 0.21W at 3.3THz by DFG in GaSe crystal.

Acknowledgment

Authors acknowledge DST (SP/S2/L-09/2001) & DRDO (ERIP/ER/0000149/M/01), Govt. of India for partial financial assistance and Prof. C Jacob, Materials Science Centre, IITKharagpur for providing some instrumental facility. The authors also acknowledge Prof. Antonio Agnesi, Pavia University, Italy, for critical appraisal of the manuscript.

References

1.

B. Ferguson and X. C. Zhang, “Materials for terahertz science and technology,” Nature Materials 1, 26–33 (2002). [CrossRef]

2.

M. Brucherseifer, M. Nagel, P. Haring Bolivar, H. Kurz, A. Bosserhoff, and R. Buttner, “Label-free probing of the binding state of DNA by time-domain terahertz sensing,” Appl. Phys. Lett. 77, 4049–4051, (2000). [CrossRef]

3.

M. A. Frerking, “Submillimeter source needs for NASA mission,” Proc. SPIE 2145, 222–229 (1994). [CrossRef]

4.

B. D. Guenther, “Terahertz sources,” Proc. SPIE 2145, 120–129 (1994). [CrossRef]

5.

W. Shei and Y. J. Ding, “Continuously tunable and coherent terahertz radiation by means of phase-matched difference frequency generation in zinc germanium phosphide,” Appl. Phys. Lett. 83, 848–850 (2003). [CrossRef]

6.

T. Taniuchi, S. Okada, and H. Nakanishi, “Widely-tunable THz-wave generation in 2–20THz range from DAST crystal by nonlinear difference frequency mixing,” Electron. Lett. 40, 60–61 (2004). [CrossRef]

7.

H. Y. Shen, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z.D. Zeng, W. J. Zhang, and Q. J. Ye, “Simultaneous multiple wavelength laser action in various Neodymium host crystals,” IEEE J. Quantum. Electron. 27, 2315–2318 (1991). [CrossRef]

8.

W. Koechner, “Solid-State Laser Engineering,” Springer, 5th Ed., pp. 46–56, 1999.

9.

R. W. Farley and P. D. Dao, “Development of an intracavity-summed multiple-wavelength Nd:YAG laser for a rugged, solid-state sodium lidar system,” Appl. Opt. 34, 4269–4273, (1995). [CrossRef] [PubMed]

10.

R. Zhou, W. Wen, Z. Cai, X. Ding, P. Wang, and J. Yao, “Efficient stable simultaneous CW dual wavelength diode-end-pumped Nd:YAG laser operating at 1.319 and 1.338 µm,” Chinese Opt. Lett. 3, 597–599, (2005).

11.

H. Y. Shen, W. X. Lin, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z. D. Zeng, W. J. Zhang, R. F. Wu, and Q. J. Ye, “1079.5- and 1341.4-nm: larger energy from a dual-wavelength Nd:YAlO3 pulsed laser,” Appl. Opt. 32, 5952–5975, (1993). [CrossRef] [PubMed]

12.

Y. Lu, B. Zhang, E. Li, D. Xu, R. Zhou, X. Zhao, F. Ji, T. Zhang, P. Wang, and J. Yao, “High-power simultaneous dual-wavelength emission of an end-pumped Nd:YAG laser using the quasi-three-level and the four-level transition,” Opt. Commun. (2006) (in press). [CrossRef]

13.

P. X. Li, D. H. Li, C. Y. Li, and Z. G. Zhang, “Simultaneous dual-wavelength continuous wave laser operation at 1.06 µm and 946 nm in Nd:YAG and their frequency doubling,” Opt. Commun. 235, 169–174, (2004). [CrossRef]

14.

J. Marling, “1.05–1.44 µm Tunability and Performance of the CW Nd3+ :YAG Laser,” IEEE J. Quantum. Electron. 14, 56–62, (1978). [CrossRef]

15.

W. Shi, Y.J. Ding, N. Fernelius, and K. Vodopyanov, “Efficient, tunable, and coherent 0.18–5.27-THz source based on GaSe crystal,” Opt. Lett. 27, 1454–1456, (2002). [CrossRef]

16.

R. L. Sutherland, “Handbook of nonlinear optics,” Marcel Dekker Inc, 87, (1996).

OCIS Codes
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3540) Lasers and laser optics : Lasers, Q-switched
(140.3580) Lasers and laser optics : Lasers, solid-state
(190.0190) Nonlinear optics : Nonlinear optics
(260.3090) Physical optics : Infrared, far

ToC Category:
Lasers and Laser Optics

History
Original Manuscript: February 6, 2006
Revised Manuscript: May 9, 2006
Manuscript Accepted: May 9, 2006
Published: May 29, 2006

Citation
Ardhendu Saha, Aniruddha Ray, Sourabh Mukhopadhyay, Nandita Sinha, Prasanta K. Datta, and Pranab K. Dutta, "Simultaneous multi-wavelength oscillation of Nd laser around 1.3 μm: A potential source for coherent terahertz generation," Opt. Express 14, 4721-4726 (2006)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-14-11-4721


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. B. Ferguson and X. C. Zhang, "Materials for terahertz science and technology," Nature Materials 1, 26-33 (2002). [CrossRef]
  2. M. Brucherseifer, M. Nagel, P. Haring Bolivar, H. Kurz, A. Bosserhoff, and R. Buttner, "Label-free probing of the binding state of DNA by time-domain terahertz sensing," Appl. Phys. Lett. 77, 4049-4051, (2000). [CrossRef]
  3. M. A. Frerking, "Submillimeter source needs for NASA mission," Proc. SPIE 2145, 222-229 (1994). [CrossRef]
  4. B. D. Guenther, "Terahertz sources," Proc. SPIE 2145, 120-129 (1994). [CrossRef]
  5. W. Shei and Y. J. Ding, "Continuously tunable and coherent terahertz radiation by means of phase-matched difference frequency generation in zinc germanium phosphide," Appl. Phys. Lett. 83, 848-850 (2003). [CrossRef]
  6. T. Taniuchi, S. Okada, and H. Nakanishi, "Widely-tunable THz-wave generation in 2-20THz range from DAST crystal by nonlinear difference frequency mixing," Electron. Lett. 40, 60-61 (2004). [CrossRef]
  7. H. Y. Shen, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z.D. Zeng, W. J. Zhang, and Q. J. Ye, "Simultaneous multiple wavelength laser action in various Neodymium host crystals," IEEE J. Quantum. Electron. 27, 2315-2318 (1991). [CrossRef]
  8. W. Koechner, "Solid-State Laser Engineering," Springer, 5th Ed., pp. 46-56, 1999.
  9. R. W. Farley and P. D. Dao, "Development of an intracavity-summed multiple-wavelength Nd:YAG laser for a rugged, solid-state sodium lidar system, " Appl. Opt. 34, 4269-4273, (1995). [CrossRef] [PubMed]
  10. R. Zhou, W. Wen, Z. Cai, X. Ding, P. Wang, and J. Yao, "Efficient stable simultaneous CW dual wavelength diode-end-pumped Nd:YAG laser operating at 1.319 and 1.338 μm," Chinese Opt. Lett. 3, 597-599, (2005).
  11. H. Y. Shen,W. X. Lin, R. R. Zeng, Y. P. Zhou, G. F. Yu, C. H. Huang, Z. D. Zeng, W. J. Zhang, R. F. Wu, and Q. J. Ye, "1079.5- and 1341.4-nm: larger energy from a dual-wavelength Nd:YAlO3 pulsed laser," Appl. Opt. 32, 5952-5975, (1993). [CrossRef] [PubMed]
  12. Y. Lu, B. Zhang, E. Li, D. Xu, R. Zhou, X. Zhao, F. Ji, T. Zhang, P. Wang, and J. Yao, "High-power simultaneous dual-wavelength emission of an end-pumped Nd:YAG laser using the quasi-three-level and the four-level transition," Opt. Commun. (2006) (in press). [CrossRef]
  13. P. X. Li, D. H. Li, C. Y. Li, and Z. G. Zhang, "Simultaneous dual-wavelength continuous wave laser operation at 1.06 μm and 946 nm in Nd:YAG and their frequency doubling," Opt. Commun. 235, 169-174, (2004). [CrossRef]
  14. J. Marling, "1.05-1.44 μm Tunability and Performance of the CW Nd3+ :YAG Laser," IEEE J. Quantum. Electron. 14, 56-62, (1978). [CrossRef]
  15. W. Shi, Y.J. Ding, N. Fernelius, and K. Vodopyanov, "Efficient, tunable, and coherent 0.18- 5.27-THz source based on GaSe crystal," Opt. Lett. 27, 1454-1456, (2002). [CrossRef]
  16. R. L. Sutherland, "Handbook of nonlinear optics," Marcel Dekker Inc, 87, (1996).

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