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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 10 — May. 9, 2011
  • pp: 9127–9138
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Suspended core subwavelength fibers: towards practical designs for low-loss terahertz guidance

Mathieu Rozé, Bora Ung, Anna Mazhorova, Markus Walther, and Maksim Skorobogatiy  »View Author Affiliations


Optics Express, Vol. 19, Issue 10, pp. 9127-9138 (2011)
http://dx.doi.org/10.1364/OE.19.009127


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Abstract

In this work we report two designs of subwavelength fibers packaged for practical terahertz wave guiding. We describe fabrication, modeling and characterization of microstructured polymer fibers featuring a subwavelength-size core suspended in the middle of a large porous outer cladding. This design allows convenient handling of the subwavelength fibers without distorting their modal profile. Additionally, the air-tight porous cladding serves as a natural enclosure for the fiber core, thus avoiding the need for a bulky external enclosure for humidity-purged atmosphere. Fibers of 5 mm and 3 mm in outer diameters with a 150 µm suspended solid core and a 900 µm suspended porous core respectively, were obtained by utilizing a combination of drilling and stacking techniques. Characterization of the fiber optical properties and the subwavelength imaging of the guided modes were performed using a terahertz near-field microscopy setup. Near-field imaging of the modal profiles at the fiber output confirmed the effectively single-mode behavior of such waveguides. The suspended core fibers exhibit transmission from 0.10 THz to 0.27 THz (larger core), and from 0.25 THz to 0.51 THz (smaller core). Due to the large fraction of power that is guided in the holey cladding, fiber propagation losses as low as 0.02 cm−1 are demonstrated specifically for the small core fiber. Low-loss guidance combined with the core isolated from environmental perturbations make these all-dielectric fibers suitable for practical terahertz imaging and sensing applications.

© 2011 OSA

1. Introduction

In the past few years, interactions between matter and terahertz waves have stimulated research especially for biomedical sensing, noninvasive imaging, non-destructive testing and spectroscopy applications [1

1. C. Jansen, S. Wietzke, O. Peters, M. Scheller, N. Vieweg, M. Salhi, N. Krumbholz, C. Jördens, T. Hochrein, and M. Koch, “Terahertz imaging: applications and perspectives,” Appl. Opt. 49(19), E48–E57 (2010). [CrossRef] [PubMed]

3

3. M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1(2), 97–105 (2007). [CrossRef]

]. However, because of high material losses in the terahertz range, the design and fabrication of low-loss waveguides for broadband terahertz transmission remains challenging. Several designs of low-loss waveguides have recently been investigated including: metallic wires [4

4. K. Wang and D. M. Mittleman, “Metal wires for terahertz wave guiding,” Nature 432(7015), 376–379 (2004). [CrossRef] [PubMed]

7

7. R. W. McGowan, G. Gallot, and D. Grischkowsky, “Propagation of ultrawideband short pulses of terahertz radiation through submillimeter-diameter circular waveguides,” Opt. Lett. 24(20), 1431–1433 (1999). [CrossRef]

], all-dielectric subwavelength polymer fibers [8

8. L.-J. Chen, H.-W. Chen, T.-F. Kao, J.-Y. Lu, and C.-K. Sun, “Low-loss subwavelength plastic fiber for terahertz waveguiding,” Opt. Lett. 31(3), 308–310 (2006). [CrossRef] [PubMed]

11

11. K. Nielsen, H. K. Rasmussen, A. J. L. Adam, P. C. M. Planken, O. Bang, and P. U. Jepsen, “Bendable, low-loss Topas fibers for the terahertz frequency range,” Opt. Express 17(10), 8592–8601 (2009). [CrossRef] [PubMed]

], Bragg fibers [12

12. M. Skorobogatiy and A. Dupuis, “Ferroelectric all-polymer hollow Bragg fibers for terahertz guidance,” Appl. Phys. Lett. 90(11), 113514 (2007). [CrossRef]

,13

13. A. Dupuis, K. Stoeffler, B. Ung, C. Dubois, and M. Skorobogatiy, “Transmission measurements of hollow-core THz Bragg Fibers,” J. Opt. Soc. Am. B (to be published).

], and dielectric metal-coated tubes [14

14. J. Harrington, R. George, P. Pedersen, and E. Mueller, “Hollow polycarbonate waveguides with inner Cu coatings for delivery of terahertz radiation,” Opt. Express 12(21), 5263–5268 (2004). [CrossRef] [PubMed]

17

17. Q. Cao and J. Jahns, “Azimuthally polarized surface plasmons as effective terahertz waveguides,” Opt. Express 13(2), 511–518 (2005). [CrossRef] [PubMed]

] to name a few.

A definite advantage of subwavelength dielectric fibers is the ease and highly efficient coupling from a conventional linearly polarized Gaussian-like beam emitted from a terahertz dipole antenna. As a main disadvantage of dielectric fibers we cite their relatively small bandwidth, which is limited towards higher frequencies due to onset of high material absorption losses; and limited at low frequencies by scattering losses [18

18. A. Dupuis, A. Mazhorova, F. Désévédavy, M. Rozé, and M. Skorobogatiy, “Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique,” Opt. Express 18(13), 13813–13828 (2010). [CrossRef] [PubMed]

23

23. A. Dupuis, J.-F. Allard, D. Morris, K. Stoeffler, C. Dubois, and M. Skorobogatiy, “Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method,” Opt. Express 17(10), 8012–8028 (2009). [CrossRef] [PubMed]

].

Currently, a key inconvenience of subwavelength dielectric fibers stems from the large fraction of power that is guided outside the high-index core. The latter feature results in strong coupling to the surrounding environment hence making subwavelength fibers difficult to manipulate and to support using holders without disrupting the signal. They also require a bulky gas-purged enclosure to minimize the effects of ambient water vapor on the measured THz spectra.

Recently, a new approach based on introducing porosity in the core, for low-loss terahertz guiding has been proposed by our group [19

19. A. Hassani, A. Dupuis, and M. Skorobogatiy, “Porous polymer fibers for low-loss Terahertz guiding,” Opt. Express 16(9), 6340–6351 (2008). [CrossRef] [PubMed]

,20

20. A. Hassani, A. Dupuis, and M. Skorobogatiy, “Low loss porous terahertz fibers containing multiple subwavelength holes,” Appl. Phys. Lett. 92(7), 071101 (2008). [CrossRef]

] and later in [21

21. S. Atakaramians, S. Afshar V, B. M. Fischer, D. Abbott, and T. M. Monro, “Porous fibers: a novel approach to low loss THz waveguides,” Opt. Express 16(12), 8845–8854 (2008). [CrossRef] [PubMed]

], and various designs of porous microstructured fibers have been proposed and fabricated [22

22. S. Atakaramians, S. Afshar V, H. Ebendorff-Heidepriem, M. Nagel, B. M. Fischer, D. Abbott, and T. M. Monro, “THz porous fibers: design, fabrication and experimental characterization,” Opt. Express 17(16), 14053–15062 (2009). [CrossRef] [PubMed]

,23

23. A. Dupuis, J.-F. Allard, D. Morris, K. Stoeffler, C. Dubois, and M. Skorobogatiy, “Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method,” Opt. Express 17(10), 8012–8028 (2009). [CrossRef] [PubMed]

]. It was also theoretically and experimentally demonstrated that the introduction of porosity enables broadening of the main transmission window compared to a non-porous fiber of the same diameter, and also blue-shifting of the transmission peak to higher frequencies [18

18. A. Dupuis, A. Mazhorova, F. Désévédavy, M. Rozé, and M. Skorobogatiy, “Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique,” Opt. Express 18(13), 13813–13828 (2010). [CrossRef] [PubMed]

].

In this work, we present the analysis of two suspended core all-dielectric fibers specifically designed for practical applications in terahertz guiding. The proposed fiber design incorporates a subwavelength-diameter core suspended inside a large porous outer cladding. We show that the purpose of the porous cladding is two-fold. First, it effectively isolates the core-guided mode from interacting with the surrounding environment, thus preventing undesirable external perturbations to affect the terahertz signal waveform. Second, it serves as a natural air-tight enclosure for the fiber core, thus avoiding the need for an externally purged housing.

The paper is organized as follows: Section 2 describes the geometry and fabrication procedure of the two suspended core fibers. Section 3 presents a detailed analysis and comparison of the output mode profiles obtained by the THz near-field imaging and numerical simulations. Section 4 presents the transmission and propagation losses in both bulk material and fibers inside the 0.01-1.00 THz range, as well as their theoretical modeling. Finally, we discuss the unique properties and potential applications of this new class of fibers.

2. Preform and fiber fabrication

All fibers in this work were fabricated using commercial rods of low density polyethylene (PE) known to be one of the lowest loss polymers in the terahertz region [24

24. J. R. Birch, J. D. Dromey, and J. Lesurf, “The optical constants of some common low-loss polymers between 4 and 40 cm−1,” Infrared Phys. 21(4), 225–228 (1981). [CrossRef]

]. The 12 cm long preform of the solid suspended core fiber was obtained by drilling three holes of 4 mm diameter, equidistantly spaced by 2 mm, and centered on a one-inch diameter rod. The preform was then drawn under pressure into a fiber of 5.1 mm outside diameter and a suspended core of dcore ∼150 µm in size. The whole cross-section of the solid suspended core fiber is presented in Fig. 1(a)
Fig. 1 (a) Cross-section of the suspended core fiber (OD = 5.1 mm), and (b) close-up view of the suspended core region (dcore ∼150 µm). (c) Cross-section of the porous core fiber (OD = 3 mm), and (d) close-up view of the suspended large porous core (dcore = 900 µm).
, with an enlarged view of the core region in Fig. 1(b).

Another fiber type that we investigated was a suspended large porous core fiber fabricated using a combination of drilling and stacking techniques. Capillaries of 0.8 mm inside diameter (ID) and 1.2 mm outside diameter (OD) were first drawn under pressure from initial PE tubes of 10 mm ID and 25.4 mm OD. Resulting capillaries were then stacked into a hexagonal lattice of 3 rings and solidified in a furnace. The stack of capillaries was then inserted in the middle of a large PE tube presenting 12 holes of 3 mm diameter in its periphery. After pressure-controlled drawing, we obtained a fiber of 3 mm OD with a porous core of approximately 900 µm in diameter suspended in the middle of the holey cladding. The structure of the porous core shows holes ranging from 20 µm to 70 µm in size, resulting in a porosity of approximately 4%. The whole cross-section of the fiber is presented in Fig. 1(c) and a detailed view of the microstructured porous core in Fig. 1(d).

3. Modal properties of the waveguides

3.1 Near-field characterization of the fiber output

In this section we investigate the principal guiding mechanisms of these fibers. Specifically, we expect that guidance by these fibers is a combination of single-mode guidance inside the subwavelength core, and anti-resonant guiding by the tube of finite thickness. Therefore the main task of this Section is to find out what excitation regimes lead to one or the other regime.

The second propagation regime in Fig. 2 is the main regime of interest for us where the field is confined in the central solid core and guided by total internal reflection as illustrated by the output profiles at 0.30 THz and 0.48 THz. One also notes that these guided modes are located inside the main low-loss propagation window (as given by the cut-back measurements) [Fig. 7(a)
Fig. 7 (a) Power propagation losses, measured by cutback, of the suspended small solid core fiber, and (b) porous core fiber as a function of frequency. Dashed line corresponds to quadratic fit of the bulk material losses.
] spanning the range between 0.28 and 0.48 THz. Moreover, the near-field profiles [in Fig. 2] indicate that transmission occurs in an effectively-single mode regime. Inspection of the values for the coupling coefficients of the first N = 12 modes (not shown here for brevity) confirms that the HE11 fundamental mode is dominantly excited inside this frequency range. As expected [in Fig. 2], field confinement becomes stronger as the frequency increases such that for f>0.50THz practically all the power propagates within the lossy solid core, thus explaining the steep increases of propagation losses over the level of bulk losses thereafter [see Fig. 7(a)].

3.2 Details of the numerical modeling of the fields at the fiber output

Finally, a finite-element method (FEM) code was used to calculate the modes of the fibers. To perform such simulation, we first imported the fiber cross-section geometries (as captured by the optical microscope) into COMSOL Multiphysics FEM software, and then solved for the complex effective refractive indices and field profiles of the first N modes (both core guided and cladding modes) where N = 12 for the suspended small solid core fiber, and N = 8 for the suspended large porous core fiber.

4. Fiber transmission and material loss measurements

4.1 Bulk polymer material: refractive index and absorption losses

We first report on the refractive index and absorption losses of the commercial polyethylene bulk material used in fiber fabrication. The data is presented in Fig. 5(a)
Fig. 5 Refractive index (a) and losses (b) of polyethylene between 0.10 THz and 1THz. The inset picture in Fig. 2(a) presents the polyethylene slab used for both measurements.
and Fig. 5(b) respectively. Characterization of refractive index and absorption losses was performed with a THz-time domain spectroscopy (TDS) setup using thick polymer slabs with parallel interfaces. The sample was prepared by cutting and polishing a 1.5 cm thick slice of the rod used for the fiber preform.

The refractive index and absorption losses of polyethylene were retrieved by fitting the predictions of a transfer matrix model to the experimental transmission data [29

29. M. Skorobogatiy and J. Yang, Fundamentals of Photonic Crystal Guiding (Cambridge University Press, 2009).

,30

30. A. Mazhorova, J. F. Gu, A. Dupuis, M. Peccianti, O. Tsuneyuki, R. Morandotti, H. Minamide, M. Tang, Y. Wang, H. Ito, and M. Skorobogatiy, “Composite THz materials using aligned metallic and semiconductor microwires, experiments and interpretation,” Opt. Express 18(24), 24632–24647 (2010). [CrossRef] [PubMed]

]. The determined refractive index [Fig. 5(a)] is largely constant between 0.10 and 1.00 THz and equal to n PE = 1.514. Power absorption losses in cm−1 of polyethylene increase quadratically as a function of frequency and can be fitted as: α [cm−1] = 0.46 f 2 − 0.1 f + 0.13 where f is the frequency in (THz) [solid line in Fig. 5(b)]. The absorption losses reach 0.2 cm−1 at 0.5 THz and about 0.5 cm−1 at 1 THz.

4.2 Fiber transmission and loss measurements

Using Eq. (1) we can now derive an expression for the intensity of the transmitted field as measured by the near field detector:
Tfiber(ω)|Eoutput(x0,y0,ω)|=|m=1NCmEm(x0,y0,ω)eiωc(neff,mLw)eαmLw2|
(4)
where (x 0, y 0) denotes the coordinates of the fiber cross-section center.

In Figs. 6(a) and 6(b) we present experimentally measured transmission spectra for different lengths of the suspended small core fiber and suspended large porous core fiber. The corresponding simulated transmission spectra of both fibers, as modeled by Eq. (4), are presented respectively in Fig. 6(c) and Fig. 6(d). We note that experimentally measured transmission spectra are well explained by the numerical simulations. Transmission through the suspended small solid core fiber covers the 0.25-0.51 THz region. A notable feature in the measured transmission spectrum of the suspended small solid core fiber [Fig. 6(a)] is presented by the sharp transmission peak located at 0.16 THz. This peak is attributed to the coupling of the Gaussian excitation beam to the cladding and surface modes that are plentiful at low frequencies. This can be also confirmed directly by looking at the near-field image of the output mode profile in Fig. 2 at 0.16 THz. Note that cladding modes exhibit high losses due to their strong confinement inside the thick and lossy cladding region. Surface modes also exhibit high losses due to their evanescent nature.

In Figs. 7(a)7(b) we present the power propagation losses of the fibers obtained from cutback measurements (black solid line) and also show (in dashed line) the quadratically increasing bulk material absorption losses obtained from measurements in Fig. 5(b). Upon examining the cutback propagation losses of the small solid core fiber [Fig. 7(a)], we find a low-loss region inside the 0.28-0.48 THz range. The loss values measured in this region are smaller in magnitude than the estimation of the absolute error [red solid line in Fig. 7(a)]. Therefore, we can only establish an upper bound value of 0.02 cm−1 for the minimum propagation loss which is defined by the average loss error inside this low-loss region. This upper bound value of 0.02 cm−1 is considerably lower than the bulk material losses in this region. In order to yield lower absolute error values in the low-loss region, it would require a setup capable of handling much longer lengths of fiber so as to accumulate greater signal attenuation before detection at the fiber output. The low-loss regime is achieved owing to the large fraction of power guided in the low-loss air cladding, as clearly revealed in the near-field profiles of Fig. 2. At lower frequencies, the highly delocalized field enhances scattering on structural imperfections such as geometrical variations in the bridges thickness. The strongly delocalized mode also enhances the field interaction with the polymer tubular cladding thus inducing high losses below 0.28 THz.

For frequencies higher than 0.48 THz, fiber propagation loss increases dramatically over the bulk material loss level. One rationale for this sharp increase in the losses is the onset of excitation − or conversion from the fundamental mode to − of a higher-order core-guided mode. Inspection of Media 1 for frequencies higher than 0.60 THz clearly reveals a two-peaked output field profile that indicates the presence of a higher-order mode. We also note that the fixed location of the near-field probe at the center of the fiber core, which coincides with the minimum trough of the two-peaked mode profile, further explains the radical drop in detected signal at these higher frequencies. Still, additional experiments are needed to confirm the origin of this threshold-like behavior.

In Fig. 7(b), corresponding to the suspended large porous core fiber, the general trend of the propagation losses is to follow that of the bulk material loss curve (in dashed line). Propagation losses increase from 0.05 cm−1 to 0.15 cm−1 between 0.10 THz and 0.40 THz; while bulk material losses quadratically rise from 0.12 cm−1 to 0.16 cm−1 in the same frequency range. The microstructured holey cladding surrounding the suspended core allows a substantial fraction of power to be guided in air, especially at low frequencies, so that propagation losses are largely lower than the bulk value between 0.05 THz to 0.20 THz: a span which roughly matches the transmission bandwidth identified in the fiber transmission spectrum [Fig. 6(b)]. We note however that beyond 0.20 THz, the 4% porosity of the core is not large enough so as to significantly lower the propagation losses below the level of bulk material absorption. We are presently working on ways to improve the fabrication of the suspended large porous core fiber to significantly increase the core porosity.

We emphasize that the key feature of the proposed fibers stems from their outer protective tubing that shields the core guided mode from interactions with the surrounding environment which enables direct and convenient manipulation of the fibers during normal operation, thus allowing practical positioning and holding of the fibers. Moreover, the protective tubing prevents the accumulation of dust and other contaminants on the surface of the fiber core that otherwise would perturb and attenuate the propagation of the guided mode. Finally we note that, to the best of our knowledge, there are currently no bending loss measurements on standard subwavelength fibers and the chief reason lies in that it is difficult to realize in practice owing to the need for fiber holders that would undoubtedly modify the mode profile; while with the proposed design this becomes a definite possibility. Further experiments are required in order to quantify the resistance of the proposed fibers to bending, and to measure the associated losses.

5. Conclusion

We demonstrate for the first time, the fabrication and near-field characterization of the two suspended core polymer fibers conveniently encapsulated for practical THz applications. Experimental measurements were confirmed by the full-vector finite-element simulations and analytical modeling. These effectively single mode fibers were designed to support large diameter modes in order to enhance their excitation by the diffraction limited Gaussian beam of a typical THz source. At the same time, the subwavelength-sized fiber cores are suspended inside of ~3-5 mm-size tubular enclosures filled with dry air to reduce their interaction with the environment, which makes such fibers convenient to handle in practical applications. Two different fiber designs were investigated, one featuring a subwavelength solid core fiber and another one featuring a large porous fiber; in both cases the cores were suspended by the network of ~10 micron-thick bridges inside a much larger diameter tube. In a stark difference with the case of bare subwavelength fibers, the power guided in suspended core fibers is isolated from external disturbances by the tubular dielectric cladding. This feature makes the suspended core fibers excellent candidates for practical terahertz signal delivery for THz near-field imaging and microscopy setups. Moreover, owing to the highly porous structure, one might envisage the use of suspended core fibers in THz sensing and spectroscopy applications with microfluidics integrated directly into the fiber structure.

The suspended small solid core fiber, in particular, offers very low-loss (0.02 cm−1) single mode guiding inside a broad continuous bandwidth (0.28-0.48 THz). This is possible due to a very large aspect ratio (34:1) between the tubular enclosure and core diameters. We note that losses can be further reduced on the low-frequency side by extending the length of the bridges, thus increasing the spacing between the central core and the polymer cladding so as to minimize detrimental interactions of the fundamental mode with the lossy polymer cladding. Moreover, the transmission window can still be further extended on the high-frequency side by reducing the core size and/or by incorporating substantial porosity within the core. The most important advantage provided by these suspended core fibers stems from the tubular cladding which effectively shields the core, and the propagating signal it supports, from perturbations in the surrounding environment therefore allowing convenient hand manipulation and positioning with holders. This last crucial property suggests that suspended core fibers offer a promising route towards practical all-dielectric THz waveguides.

References and links

1.

C. Jansen, S. Wietzke, O. Peters, M. Scheller, N. Vieweg, M. Salhi, N. Krumbholz, C. Jördens, T. Hochrein, and M. Koch, “Terahertz imaging: applications and perspectives,” Appl. Opt. 49(19), E48–E57 (2010). [CrossRef] [PubMed]

2.

P. H. Siegel, “Terahertz technology in biology and medicine,” IEEE Trans. Microw. Theory Tech. 52(10), 2438–2447 (2004). [CrossRef]

3.

M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1(2), 97–105 (2007). [CrossRef]

4.

K. Wang and D. M. Mittleman, “Metal wires for terahertz wave guiding,” Nature 432(7015), 376–379 (2004). [CrossRef] [PubMed]

5.

T. Jeon, J. Zhang, and D. Grischkowsky, “THz Sommerfeld wave propagation on a single metal wire,” Appl. Phys. Lett. 86(16), 161904 (2005). [CrossRef]

6.

R. Mendis and D. Grischkowsky, “THz interconnect with low-loss and low-group velocity dispersion,” IEEE Microw. Wirel. Compon. Lett. 11(11), 444–446 (2001). [CrossRef]

7.

R. W. McGowan, G. Gallot, and D. Grischkowsky, “Propagation of ultrawideband short pulses of terahertz radiation through submillimeter-diameter circular waveguides,” Opt. Lett. 24(20), 1431–1433 (1999). [CrossRef]

8.

L.-J. Chen, H.-W. Chen, T.-F. Kao, J.-Y. Lu, and C.-K. Sun, “Low-loss subwavelength plastic fiber for terahertz waveguiding,” Opt. Lett. 31(3), 308–310 (2006). [CrossRef] [PubMed]

9.

H. Han, H. Park, M. Cho, and J. Kim, “Terahertz pulse propagation in a plastic photonic crystal fiber,” Appl. Phys. Lett. 80(15), 2634–2636 (2002). [CrossRef]

10.

M. Nagel, A. Marchewka, and H. Kurz, “Low-index discontinuity terahertz waveguides,” Opt. Express 14(21), 9944–9954 (2006). [CrossRef] [PubMed]

11.

K. Nielsen, H. K. Rasmussen, A. J. L. Adam, P. C. M. Planken, O. Bang, and P. U. Jepsen, “Bendable, low-loss Topas fibers for the terahertz frequency range,” Opt. Express 17(10), 8592–8601 (2009). [CrossRef] [PubMed]

12.

M. Skorobogatiy and A. Dupuis, “Ferroelectric all-polymer hollow Bragg fibers for terahertz guidance,” Appl. Phys. Lett. 90(11), 113514 (2007). [CrossRef]

13.

A. Dupuis, K. Stoeffler, B. Ung, C. Dubois, and M. Skorobogatiy, “Transmission measurements of hollow-core THz Bragg Fibers,” J. Opt. Soc. Am. B (to be published).

14.

J. Harrington, R. George, P. Pedersen, and E. Mueller, “Hollow polycarbonate waveguides with inner Cu coatings for delivery of terahertz radiation,” Opt. Express 12(21), 5263–5268 (2004). [CrossRef] [PubMed]

15.

B. Bowden, J. A. Harrington, and O. Mitrofanov, “Silver/polystyrene-coated hollow glass waveguides for the transmission of terahertz radiation,” Opt. Lett. 32(20), 2945–2947 (2007). [CrossRef] [PubMed]

16.

T. Ito, Y. Matsuura, M. Miyagi, H. Minamide, and H. Ito, “Flexible terahertz fiber optics with low bend-induced losses,” J. Opt. Soc. Am. B 24(5), 1230–1235 (2007). [CrossRef]

17.

Q. Cao and J. Jahns, “Azimuthally polarized surface plasmons as effective terahertz waveguides,” Opt. Express 13(2), 511–518 (2005). [CrossRef] [PubMed]

18.

A. Dupuis, A. Mazhorova, F. Désévédavy, M. Rozé, and M. Skorobogatiy, “Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique,” Opt. Express 18(13), 13813–13828 (2010). [CrossRef] [PubMed]

19.

A. Hassani, A. Dupuis, and M. Skorobogatiy, “Porous polymer fibers for low-loss Terahertz guiding,” Opt. Express 16(9), 6340–6351 (2008). [CrossRef] [PubMed]

20.

A. Hassani, A. Dupuis, and M. Skorobogatiy, “Low loss porous terahertz fibers containing multiple subwavelength holes,” Appl. Phys. Lett. 92(7), 071101 (2008). [CrossRef]

21.

S. Atakaramians, S. Afshar V, B. M. Fischer, D. Abbott, and T. M. Monro, “Porous fibers: a novel approach to low loss THz waveguides,” Opt. Express 16(12), 8845–8854 (2008). [CrossRef] [PubMed]

22.

S. Atakaramians, S. Afshar V, H. Ebendorff-Heidepriem, M. Nagel, B. M. Fischer, D. Abbott, and T. M. Monro, “THz porous fibers: design, fabrication and experimental characterization,” Opt. Express 17(16), 14053–15062 (2009). [CrossRef] [PubMed]

23.

A. Dupuis, J.-F. Allard, D. Morris, K. Stoeffler, C. Dubois, and M. Skorobogatiy, “Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method,” Opt. Express 17(10), 8012–8028 (2009). [CrossRef] [PubMed]

24.

J. R. Birch, J. D. Dromey, and J. Lesurf, “The optical constants of some common low-loss polymers between 4 and 40 cm−1,” Infrared Phys. 21(4), 225–228 (1981). [CrossRef]

25.

A. Bitzer, H. Helm, and M. Walther, “Beam-profiling and wavefront-sensing of THz pulses at the focus of a substrate-lens,” IEEE J. Sel. Top. Quantum Electron. 14(2), 476–481 (2008). [CrossRef]

26.

A. Bitzer, A. Ortner, and M. Walther, “Terahertz near-field microscopy with subwavelength spatial resolution based on photoconductive antennas,” Appl. Opt. 49(19), E1–E6 (2010). [CrossRef] [PubMed]

27.

A. Bitzer and M. Walther, “Terahertz near-field imaging of metallic subwavelength holes and hole arrays,” Appl. Phys. Lett. 92(23), 231101 (2008). [CrossRef]

28.

C.-H. Lai, B. You, J.-Y. Lu, T.-A. Liu, J.-L. Peng, C.-K. Sun, and H.-C. Chang, “Modal characteristics of antiresonant reflecting pipe waveguides for terahertz waveguiding,” Opt. Express 18(1), 309–322 (2010). [CrossRef] [PubMed]

29.

M. Skorobogatiy and J. Yang, Fundamentals of Photonic Crystal Guiding (Cambridge University Press, 2009).

30.

A. Mazhorova, J. F. Gu, A. Dupuis, M. Peccianti, O. Tsuneyuki, R. Morandotti, H. Minamide, M. Tang, Y. Wang, H. Ito, and M. Skorobogatiy, “Composite THz materials using aligned metallic and semiconductor microwires, experiments and interpretation,” Opt. Express 18(24), 24632–24647 (2010). [CrossRef] [PubMed]

OCIS Codes
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(160.5470) Materials : Polymers
(060.4005) Fiber optics and optical communications : Microstructured fibers
(180.4243) Microscopy : Near-field microscopy
(300.6495) Spectroscopy : Spectroscopy, teraherz
(110.6795) Imaging systems : Terahertz imaging

ToC Category:
Fiber Optics and Optical Communications

History
Original Manuscript: February 7, 2011
Revised Manuscript: April 13, 2011
Manuscript Accepted: April 20, 2011
Published: April 26, 2011

Virtual Issues
Vol. 6, Iss. 6 Virtual Journal for Biomedical Optics

Citation
Mathieu Rozé, Bora Ung, Anna Mazhorova, Markus Walther, and Maksim Skorobogatiy, "Suspended core subwavelength fibers: towards practical designs for low-loss terahertz guidance," Opt. Express 19, 9127-9138 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-10-9127


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References

  1. C. Jansen, S. Wietzke, O. Peters, M. Scheller, N. Vieweg, M. Salhi, N. Krumbholz, C. Jördens, T. Hochrein, and M. Koch, “Terahertz imaging: applications and perspectives,” Appl. Opt. 49(19), E48–E57 (2010). [CrossRef] [PubMed]
  2. P. H. Siegel, “Terahertz technology in biology and medicine,” IEEE Trans. Microw. Theory Tech. 52(10), 2438–2447 (2004). [CrossRef]
  3. M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1(2), 97–105 (2007). [CrossRef]
  4. K. Wang and D. M. Mittleman, “Metal wires for terahertz wave guiding,” Nature 432(7015), 376–379 (2004). [CrossRef] [PubMed]
  5. T. Jeon, J. Zhang, and D. Grischkowsky, “THz Sommerfeld wave propagation on a single metal wire,” Appl. Phys. Lett. 86(16), 161904 (2005). [CrossRef]
  6. R. Mendis and D. Grischkowsky, “THz interconnect with low-loss and low-group velocity dispersion,” IEEE Microw. Wirel. Compon. Lett. 11(11), 444–446 (2001). [CrossRef]
  7. R. W. McGowan, G. Gallot, and D. Grischkowsky, “Propagation of ultrawideband short pulses of terahertz radiation through submillimeter-diameter circular waveguides,” Opt. Lett. 24(20), 1431–1433 (1999). [CrossRef]
  8. L.-J. Chen, H.-W. Chen, T.-F. Kao, J.-Y. Lu, and C.-K. Sun, “Low-loss subwavelength plastic fiber for terahertz waveguiding,” Opt. Lett. 31(3), 308–310 (2006). [CrossRef] [PubMed]
  9. H. Han, H. Park, M. Cho, and J. Kim, “Terahertz pulse propagation in a plastic photonic crystal fiber,” Appl. Phys. Lett. 80(15), 2634–2636 (2002). [CrossRef]
  10. M. Nagel, A. Marchewka, and H. Kurz, “Low-index discontinuity terahertz waveguides,” Opt. Express 14(21), 9944–9954 (2006). [CrossRef] [PubMed]
  11. K. Nielsen, H. K. Rasmussen, A. J. L. Adam, P. C. M. Planken, O. Bang, and P. U. Jepsen, “Bendable, low-loss Topas fibers for the terahertz frequency range,” Opt. Express 17(10), 8592–8601 (2009). [CrossRef] [PubMed]
  12. M. Skorobogatiy and A. Dupuis, “Ferroelectric all-polymer hollow Bragg fibers for terahertz guidance,” Appl. Phys. Lett. 90(11), 113514 (2007). [CrossRef]
  13. A. Dupuis, K. Stoeffler, B. Ung, C. Dubois, and M. Skorobogatiy, “Transmission measurements of hollow-core THz Bragg Fibers,” J. Opt. Soc. Am. B (to be published).
  14. J. Harrington, R. George, P. Pedersen, and E. Mueller, “Hollow polycarbonate waveguides with inner Cu coatings for delivery of terahertz radiation,” Opt. Express 12(21), 5263–5268 (2004). [CrossRef] [PubMed]
  15. B. Bowden, J. A. Harrington, and O. Mitrofanov, “Silver/polystyrene-coated hollow glass waveguides for the transmission of terahertz radiation,” Opt. Lett. 32(20), 2945–2947 (2007). [CrossRef] [PubMed]
  16. T. Ito, Y. Matsuura, M. Miyagi, H. Minamide, and H. Ito, “Flexible terahertz fiber optics with low bend-induced losses,” J. Opt. Soc. Am. B 24(5), 1230–1235 (2007). [CrossRef]
  17. Q. Cao and J. Jahns, “Azimuthally polarized surface plasmons as effective terahertz waveguides,” Opt. Express 13(2), 511–518 (2005). [CrossRef] [PubMed]
  18. A. Dupuis, A. Mazhorova, F. Désévédavy, M. Rozé, and M. Skorobogatiy, “Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique,” Opt. Express 18(13), 13813–13828 (2010). [CrossRef] [PubMed]
  19. A. Hassani, A. Dupuis, and M. Skorobogatiy, “Porous polymer fibers for low-loss Terahertz guiding,” Opt. Express 16(9), 6340–6351 (2008). [CrossRef] [PubMed]
  20. A. Hassani, A. Dupuis, and M. Skorobogatiy, “Low loss porous terahertz fibers containing multiple subwavelength holes,” Appl. Phys. Lett. 92(7), 071101 (2008). [CrossRef]
  21. S. Atakaramians, S. Afshar V, B. M. Fischer, D. Abbott, and T. M. Monro, “Porous fibers: a novel approach to low loss THz waveguides,” Opt. Express 16(12), 8845–8854 (2008). [CrossRef] [PubMed]
  22. S. Atakaramians, S. Afshar V, H. Ebendorff-Heidepriem, M. Nagel, B. M. Fischer, D. Abbott, and T. M. Monro, “THz porous fibers: design, fabrication and experimental characterization,” Opt. Express 17(16), 14053–15062 (2009). [CrossRef] [PubMed]
  23. A. Dupuis, J.-F. Allard, D. Morris, K. Stoeffler, C. Dubois, and M. Skorobogatiy, “Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method,” Opt. Express 17(10), 8012–8028 (2009). [CrossRef] [PubMed]
  24. J. R. Birch, J. D. Dromey, and J. Lesurf, “The optical constants of some common low-loss polymers between 4 and 40 cm−1,” Infrared Phys. 21(4), 225–228 (1981). [CrossRef]
  25. A. Bitzer, H. Helm, and M. Walther, “Beam-profiling and wavefront-sensing of THz pulses at the focus of a substrate-lens,” IEEE J. Sel. Top. Quantum Electron. 14(2), 476–481 (2008). [CrossRef]
  26. A. Bitzer, A. Ortner, and M. Walther, “Terahertz near-field microscopy with subwavelength spatial resolution based on photoconductive antennas,” Appl. Opt. 49(19), E1–E6 (2010). [CrossRef] [PubMed]
  27. A. Bitzer and M. Walther, “Terahertz near-field imaging of metallic subwavelength holes and hole arrays,” Appl. Phys. Lett. 92(23), 231101 (2008). [CrossRef]
  28. C.-H. Lai, B. You, J.-Y. Lu, T.-A. Liu, J.-L. Peng, C.-K. Sun, and H.-C. Chang, “Modal characteristics of antiresonant reflecting pipe waveguides for terahertz waveguiding,” Opt. Express 18(1), 309–322 (2010). [CrossRef] [PubMed]
  29. M. Skorobogatiy and J. Yang, Fundamentals of Photonic Crystal Guiding (Cambridge University Press, 2009).
  30. A. Mazhorova, J. F. Gu, A. Dupuis, M. Peccianti, O. Tsuneyuki, R. Morandotti, H. Minamide, M. Tang, Y. Wang, H. Ito, and M. Skorobogatiy, “Composite THz materials using aligned metallic and semiconductor microwires, experiments and interpretation,” Opt. Express 18(24), 24632–24647 (2010). [CrossRef] [PubMed]

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