OSA's Digital Library

Optical Materials Express

Optical Materials Express

  • Editor: David J. Hagan
  • Vol. 1, Iss. 7 — Nov. 1, 2011
  • pp: 1332–1340
« Show journal navigation

Wideband-rejection filters and reflection-hole filters of chalcogenide glass for circularly polarized IR-A and IR-B radiation

Drew P. Pulsifer, Raúl J. Martín-Palma, Stephen E. Swiontek, Carlo G. Pantano, and Akhlesh Lakhtakia  »View Author Affiliations


Optical Materials Express, Vol. 1, Issue 7, pp. 1332-1340 (2011)
http://dx.doi.org/10.1364/OME.1.001332


View Full Text Article

Acrobat PDF (1166 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Compact infrared filters—either to reject infrared radiation of a specific circular-polarization state in a wide band or to transmit the same radiation in a narrow band—for the IR-A and IR-B spectral regimes were designed and fabricated by thermal evaporation of chalcogenide glass of nominal composition Ge28Sb12Se60 in a vacuum chamber.

© 2011 OSA

1. Introduction

Chalcogenide glasses are ideally suited for fabrication of thin-film optical devices that operate in the near- to far-infrared spectral regimes [1

1. J. A. Savage and S. Nielsen, “Chalcogenide glasses transmitting in the infrared between 1 and 20 μ — A state of the art review,” Infrared Phys. 195, 195–204 (1965). [CrossRef]

4

4. A. R. Hilton Sr., Chalcogenide Glasses for Infrared Optics (McGraw–Hill, 2010).

]. The selenide system offers low melting and evaporation temperatures, a wide range of glass-forming compositions that permit both engineering design of the refractive index and high transmittance in the 1-to-12-μm wavelength regime. The GeSbSe system is highly covalent with excellent thermal and other physical properties, and through composition control, can be rendered electrically conductive or photoconductive. Although these chalcogenide glasses are hard to process in bulk without the introduction of water and oxygen impurities (and associated absorption bands in the infrared spectral regime), those problems are highly suppressed in thin films of these materials. It is also worth mentioning that these materials can exhibit phase-change behavior which could introduce other functionalities into chalcogenide-glass-based infrared optical devices.

In a research program to develop the use of chalcogenide glasses for free-space optics in the 1-to-3-μm wavelength regime, we decided to fabricate circular-polarization filters. Circularly polarized light in this regime is commonly generated by transmission of light first through a linear polarizer and then through a quarter wave plate, typically made of a birefringent crystal such as quartz [5

5. A. Saha, K. Bhattacharya, and A. K. Chakraborty, “Reconfigurable achromatic half-wave and quarter-wave retarder in near infrared using crystalline quartz plates,” Opt. Eng. 50, 034004 (2011). [CrossRef]

]. However, a compact wideband filter that rejects one of the two circular polarization states but allows the other circular polarization state to pass through with sufficient transmittance appears to be uavailable for the 1-to-3-μm wavelength regime. This kind of filter should require the use of a structurally chiral material [6

6. A. Lakhtakia and M. W. McCall, “Circular polarization filters,” in Encyclopedia of Optical Engineering, R. G. Driggers, ed. (Marcel Dekker, 2003), pp. 230–236.

] made of a material that is transparent in that wavelength regime.

Therefore, we decided to fabricate circular-polarization filters for the IR-A (700–1400 nm) and IR-B (1400–3000 nm) spectral regimes by the vacuum deposition of chiral sculptured thin films (STFs) [7

7. A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]

] of a commercially available chalcogenide glass with nominal composition Ge28Sb12Se60. This material can be easily evaporated by resistive heating in a vacuum chamber and deposited as a thin film with columnar morphology [8

8. R. J. Martín-Palma, J. V. Ryan, and C. G. Pantano, “Spectral behavior of the optical constants in the visible/NIR of GeSbSe chalcogenide thin films grown at glancing angle,” J. Vac. Sci. Technol. A 25, 587–591 (2007). [CrossRef]

, 9

9. R. J. Martín-Palma, F. Zhang, A. Lakhtakia, A. Cheng, J. Xu, and C. G. Pantano, “Retardance of chalcogenide thin films grown by the oblique-angle-deposition technique,” Thin Solid Films 517, 5553–5556 (2009). [CrossRef]

]. Its bulk refractive index is large and it is weakly dissipative in the IR-A and IR-B spectral regimes. Chiral STFs made of chalcogenide glasses have not been reported previously.

A chiral STF is an assembly of parallel and upright helical columns of sufficiently small cross-sectional diameter so that it can be considered as a unidirectionally nonhomogeneous, dielectric continuum whose relative permittivity dyadic [10

10. H. C. Chen, Theory of Electromagnetic Waves: A Coordinate-free Approach (McGraw–Hill, 1983).

] rotates in a helical fashion along the direction of nonhomogeneity. It is thus a structurally chiral material and can function as a wideband-rejection filter for circularly polarized radiation of the same handedness as that of its own helical columns [11

11. Q. Wu, I. J. Hodgkinson, and A. Lakhtakia, “Circular polarization filters made of chiral sculptured thin films: experimental and simulation results,” Opt. Eng. 39, 1863–1868 (2000). [CrossRef]

]. Once an appropriate bulk material has been chosen, the spectral regime of operation can be engineered quite simply though the structural period (i.e., the pitch) and the angle of rise of the helical columns. A chiral STF with a central phase defect can function as a narrowband spectral-hole filter for circularly polarized radiation of the same handedness as that of its own helical columns [12

12. A. Lakhtakia, “Generation of spectral holes by inserting central structurally chiral layer defects in periodic structurally chiral materials,” Opt. Commun. 275, 283–287 (2007). [CrossRef]

].

The plan of this paper is as follows. Section 2 provides a brief description of the theory underlying the performance of both types of circular-polarization filters. The vacuum deposition process adopted is presented in Sec. 3, and the fabricated filters are characterized in Sec. 4. Many different types of central phase defects [12

12. A. Lakhtakia, “Generation of spectral holes by inserting central structurally chiral layer defects in periodic structurally chiral materials,” Opt. Commun. 275, 283–287 (2007). [CrossRef]

] can be implemented, but the one we have chosen here is the central 90°-twist defect [13

13. I. J. Hodgkinson, Q. H. Wu, K. E. Thorn, A. Lakhtakia, and M. W. McCall, “Spacerless circular-polarization spectral-hole filters using chiral sculptured thin films: theory and experiment,” Opt. Commun. 184, 57–66 (2000). [CrossRef]

15

15. J. Schmidtke and W. Stille, “Photonic defect modes in cholesteric liquid crystal films,” Eur. Phys. J. E 12, 553–564 (2003). [CrossRef]

].

2. Theory in brief

For our purposes, a chiral STF is viewed as an electromagnetic continuum that completely occupies the region between the planes z = −L and z = L. Whereas the relative permeability of the chiral STF is unity, its permittivity dyadic is stated as follows [7

7. A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]

]:
ɛ__(z)=ɛ0S__z(z)S__y(χ)[ɛau^_zu^_z+ɛbu^_xu^_x+ɛcu^_yu^_y]S__y1(χ)S__z1(z),z[L,L],
(1)
where ɛ0 is the permittivity of free space; ɛa,b,c are the reference relative permittivity scalars, all possibly functions of the angular frequency ω; and the Cartesian unit vectors are identified as ûx, ûy, and ûz.

The dyadic
S__y(χ)=u^_yu^_y+(u^_xu^_x+u^_zu^_z)cosχ+(u^_zu^_xu^_xu^_z)sinχ
(2)
represents the locally aciculate morphology of the chiral STF, with χ ∈ (0,π/2] as the angle of rise; in general, ɛaɛbɛc. The rotation dyadic [7

7. A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]

]
S__z(z)=(u^_xu^_x+u^_yu^_y)cos[πΩz+γ±]+h(u^_yu^_xu^_xu^_y)sin[πΩz+γ±]+u^_zu^_z,{z>0z<0,
(3)
indicates both the helical morphology of the chiral STF and the central twist defect therein. In the foregoing expression, 2Ω is the structural period, and the parameter h = 1 for structural right-handedness but h = −1 for structural left-handedness. The beginning of the helical variation of the permittivity dyadic is offset relative to the x axis in the xy plane by an angle γ+ for z > 0, and by an angle γ for z < 0. When |γ+γ|modπ ≠ 0, a central twist defect is located at z = 0, the twist defect being quantified by the jump angle γ+γ. Comparison between theory and experiment indicates that the foregoing constitutive description is sufficient for design purposes [16

16. J. A. Sherwin, A. Lakhtakia, and I. J. Hodgkinson, “On calibration of a nominal structure-property relationship model for chiral sculptured thin films by axial transmittance measurements,” Opt. Commun. 2009, 369–375 (2002). [CrossRef]

].

Provided that circularly polarized radiation is normally incident on the chiral STF, the ratio N = L/2Ω is sufficiently large, and |γ+γ|modπ = 0, the circular Bragg phenomenon may be exhibited as follows: If the handedness of the incident radiation is the same as the structural handedness of the chiral STF, and the free-space wavelength of the incident radiation lies within a spectral regime called the circular Bragg regime, the reflectance is very high and the reflected radiation is mostly co-polarized [7

7. A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]

, 11

11. Q. Wu, I. J. Hodgkinson, and A. Lakhtakia, “Circular polarization filters made of chiral sculptured thin films: experimental and simulation results,” Opt. Eng. 39, 1863–1868 (2000). [CrossRef]

]. The reflectance is very low when the two handednesses are not the same. With the twin assumptions that dispersion of the constitutive parameters is sufficiently weak in the neighborhood of the circular Bragg regime and that dissipation is weak enough to be ignored, the circular Bragg regime may be estimated [17

17. J. B. Geddes III and A. Lakhtakia, “Quantification of optical pulsed-plane-wave-shaping by chiral sculptured thin films,” J. Mod. Opt. 53, 2763–2783 (2006). [CrossRef]

] as λ0[2Ωɛc,2Ωɛd], where
ɛd=ɛaɛb/(ɛacos2χ+ɛbsin2χ)1/2,
(4)
and the free-space wavelength λ0=(2π/ω)/ɛ0μ0 with μ0 as the free-space permeability.

The calculated transmittances TRR, TLL, TLR, and TRL are plotted in Fig. 1 as functions of the free-space wavelength λ0 for a chiral STF without a central phase defect. The notation TRL indicates the efficiency of transmission of an incident LCP plane wave as an RCP plane wave. The relevant parameters of the chiral STF are as follows: N = 8, h = +1, Ω = 350 nm, ɛc = 2.89, ɛd = 3.24, and γ+γ = 0. Within the circular Bragg regime λ0 ∈ [1190, 1260] nm, an incident right-circularly polarized (RCP) plane wave will suffer high reflection, but an incident left-circularly polarized (LCP) plane wave will undergo high transmission, both without significant change of polarization state. Accordingly, TRR, TLR, and TRL must be very weak in the circular Bragg regime, whereas TLL must have a high magnitude, which is confirmed by the plots in Fig. 1. Thus, a chiral STF without a central phase defect is a wideband rejection filter for co-handed circularly polarized radiation, which has already been demonstrated experimentally in the visible regime [11

11. Q. Wu, I. J. Hodgkinson, and A. Lakhtakia, “Circular polarization filters made of chiral sculptured thin films: experimental and simulation results,” Opt. Eng. 39, 1863–1868 (2000). [CrossRef]

].

Fig. 1 Calculated transmittances TRR, TLL, TLR, and TRL as functions of the free-space wavelength λ0 when a plane wave is normally incident on a chiral STF without a central phase defect. The relevant parameters of the chiral STF are as follows: N = 8, h = +1, Ω = 350 nm, ɛc = 2.89, ɛd = 3.24, and γ+γ = 0. Interchange the subscripts L and R in the transmittances for h = −1.

Fig. 2 Same as Fig. 1, except that γ+γ = 90°.

Parenthetically, when N is very large and γ+γ = 90°, theory predicts [12

12. A. Lakhtakia, “Generation of spectral holes by inserting central structurally chiral layer defects in periodic structurally chiral materials,” Opt. Commun. 275, 283–287 (2007). [CrossRef]

, 14

14. V. I. Kopp and A. Z. Genack, “Twist defect in chiral photonic structures,” Phys. Rev. Lett. 89, 033901 (2002). [CrossRef] [PubMed]

, 15

15. J. Schmidtke and W. Stille, “Photonic defect modes in cholesteric liquid crystal films,” Eur. Phys. J. E 12, 553–564 (2003). [CrossRef]

] that the narrowband spike in the transmittance spectrum for co-handed incident circularly polarized radiation in Fig. 2 is replaced by an ultranarrowband hole in the transmittance spectrum for cross-handed incident circularly polarized radiation. However, that phenomenon has not been experimentally verified because even weak dissipation in the chiral STF is inimical to its existence [18

18. F. Wang and A. Lakhtakia, “Specular and nonspecular, thickness-dependent, spectral holes in a slanted chiral sculptured thin film with a central twist defect,” Opt. Commun. 215, 79–92 (2003). [CrossRef]

], although a new scheme has been recently formulated for experimental verification [19

19. F. Wang and A. Lakhtakia, “Complete exhibition of defect-mode resonance despite dissipation in structurally chiral materials,” Phys. Rev. B 83, 075115 (2011). [CrossRef]

].

3. Device fabrication

In order to make both wideband-rejection filters and reflection-hole filters, all chiral STFs were deposited on 25 mm × 76 mm pre-cleaned borosilicate glass microscope slides (Fisherfinest premium microscope slides) as substrates. Each substrate was attached with kapton tape to a 75-mm-diameter stainless-steel substrate holder. This assembly was then placed in a vacuum chamber which was pumped to a base pressure of ∼ 2 × 10−6 Torr prior to deposition. The chalcogenide glass with nominal composition Ge28Sb12Se60 (commercially available from Schott North America) was then thermally evaporated from a dimpled tungsten boat (R. D. Mathis P/N S9E-.010W) located 14 cm below the substrate. The deposition rate and the total thickness of the growing chiral STF were monitored in situ by a quartz crystal monitor (QCM). The deposition rate was held constant during the growth of the chiral STF by adjusting the current passing through the tungsten boat and monitoring the rate indicated by the QCM. Currents of magnitude between 192 and 199 A were required to maintain the desired deposition rates. The duration of the depositions ranged from 138 to 168 min, depending on the total thickness 4NΩ of the chiral STF.

The motion of the substrate was controlled by a pair of computer-controlled stepper motors. The first motor controls the angle χv between the substrate plane (the xy plane) and the average direction of the incident vapor flux. This angle, fixed at 15° for all samples fabricated for this research, is crucial to the control of ɛa,b,c and χ [20

20. R. Messier, T. Gehrke, C. Frankel, V. C. Venugopal, W. Otaño, and A. Lakhtakia, “Engineered sculptured nematic thin films,” J. Vac. Sci. Technol. A 15, 2148–2152 (1997). [CrossRef]

, 21

21. I. J. Hodgkinson, Q. H. Wu, and J. Hazel, “Empirical equations for the principal refractive indices and column angle of obliquely deposited films of tantalum oxide, titanium oxide, and zirconium oxide,” Appl. Opt. 37, 2653–2659 (1998). [CrossRef]

]. The second stepper motor controls the rotation of the substrate about the central axis perpendicular to the substrate plane, this axis being designated as the z axis. Coordination between the deposition rate and the rotation motor allows for the variation of the morphology of the chiral STF, when the angle χv is fixed.

A technique called serial bi-deposition (SBD), originally devised to produce highly anisotropic columnar thin films [22

22. I. Hodgkinson and Q. H. Wu, “Vacuum deposited biaxial thin films with all principal axes inclined to the substrate,” J. Vac. Sci. Technol. A 17, 2928–2932 (1999). [CrossRef]

, 23

23. I. Hodgkinson and Q. H. Wu, “Serial bideposition of anisotropic thin films with enhanced linear birefringence,” Appl. Opt. 38, 3621–3625 (1999). [CrossRef]

], was adapted to produce chiral STFs with high contrast between ɛc and ɛd [24

24. I. Hodgkinson, Q. H. Wu, B. Knight, A. Lakhtakia, and K. Robbie, “Vacuum deposition of chiral sculptured thin films with high optical activity,” Appl. Opt. 39, 642–649 (2000). [CrossRef]

]. The higher the contrast, the smaller the value of N needed to produce a satisfactory wideband filter. In the SBD process, deposition occurs as a sequence of discrete sub-depositions [24

24. I. Hodgkinson, Q. H. Wu, B. Knight, A. Lakhtakia, and K. Robbie, “Vacuum deposition of chiral sculptured thin films with high optical activity,” Appl. Opt. 39, 642–649 (2000). [CrossRef]

, 25

25. S. Pursel and M. W. Horn, “Prospects for nanowire sculptured-thin-film devices,” J. Vac. Sci. Technol. B 25, 2611–2615 (2007). [CrossRef]

].

In order to produce chiral STFs, the following SBD methodology was adopted: The fabrication begins with a sub-deposition for just 2 s on the stationary substrate, followed by quick rotation in 0.5 s of the substrate by 183° about the z axis during which minimal deposition occurs, followed by another sub-deposition for 2 s on the stationary substrate, and so on. The two-step cycle was repeated 120 times to produce one structural period, of thickness 2Ω, of the chiral STF.

In order to fabricate a wideband-rejection filter, the cycle was repeated 240N times. For the fabrication of a narrowband reflection-hole filter, the SBD process was carried out for 120N cycles, the substrate was quickly rotated a quarter turn about the z axis, and the SBD process was resumed for another 120N cycles.

The structural period of the chiral STF can be altered by adjusting the duration of the sub-depositions while maintaining a constant deposition rate, or conversely by altering the deposition rate while maintaining the sub-deposition duration. We chose to maintain the deposition rate while the sub-deposition duration was altered to produce the desired structural period. With a deposition rate of 1.15 nm s−1, we fabricated chiral STFs with Ω = 300 nm in test runs.

4. Structural and optical characterization

Let us now present data on the following two devices fabricated for this paper:
  1. a wideband-rejection filter, labeled WRF, with Ω = 350 nm; and
  2. a narrowband reflection-hole filter, labeled RHF, with Ω = 400 nm.

For both devices, we fixed h = +1 and N = 8. The structural periods were chosen based on spectral measurements of reflectance and transmittance of columnar thin films made of chalcogenide glass, whereby the value of the composite refractive index
nBr=(1/2)(ɛc+ɛd)
(5)
is expected to lie between 1.67 and 2.0 for λ0 ∈ [1000,2400] nm (Fig. 3 of [8

8. R. J. Martín-Palma, J. V. Ryan, and C. G. Pantano, “Spectral behavior of the optical constants in the visible/NIR of GeSbSe chalcogenide thin films grown at glancing angle,” J. Vac. Sci. Technol. A 25, 587–591 (2007). [CrossRef]

]), with dissipation assumed weak enough to be ignored. Let us note here that the center wavelength of the circular Bragg regime of a nondissipative and nondispersive chiral STF can be estimated as 2ΩnBr.

Fig. 3 Cross-sectional SEM images of (a) WRF and (b) RHF. The arrow indicates the location of the central 90°-twist defect in RHF.

Both devices were characterized by measuring the transmittances TRR, TLL, TLR, and TRL for normal incidence as functions of the free-space wavelength λ0 on a Perkin-Elmer Lambda 950 UV/Vis/NIR spectrophotometer with the standard detector module installed. This is a double-beam, double-monochromator-ratio recording system with prealigned tungsten-halogen and deuterium lamps as sources. The wavelength reproducibility is 0.02 nm in the near-infrared regime. Combinations of an adjustable linear polarizer and a Fresnel rhomb retarder were mounted on either side of the device (either WRF or RHF) between the source and detector ports of the spectrophotometer.

The circular Bragg regime of WRF is almost fully developed, with a center wavelength of 1225 nm and a full-width-at-half-maximum bandwidth of ∼ 80 nm in the plot of TRR in Fig. 4. Whereas TLL < 10% for about 25 nm on either side of the center wavelength, TRR > 58% over the same wavelength regime, signifying acceptable performance as a wideband-rejection filter. Increasing N somewhat could enhance the performance, and the proper selection of χv would also assist in that goal. Furthermore, the ratio of the center wavelength (1225 nm) to the structural period (700 nm) equals 1.75, which lies on the lower side of the center of the estimated range (1.67 to 2) of nBr.

Fig. 4 Measured transmittances TRR, TLL, TLR, and TRL of the device labeled as WRF (Ω = 350 nm) as functions of the free-space wavelength λ0. The device was fabricated of chalcogenide glass with nominal composition Ge28Sb12Se60 and its helical columns have 2N = 16 complete turns. Data were acquired at 2-nm λ0-intervals.

The center wavelength of the TRR spike of RHF is 1445 nm in Fig. 5, whereas the structural period is 800 nm. The ratio of the former to the latter is 1.81, quite in the center of the estimated range of nBr. The full-width-at-half-maximum bandwidth of the spike in the plot of TRR is 18 nm, with a peak at 52%. Calculations show that the peak value could continue to rise with N, reach a maximum and then begin falling down [12

12. A. Lakhtakia, “Generation of spectral holes by inserting central structurally chiral layer defects in periodic structurally chiral materials,” Opt. Commun. 275, 283–287 (2007). [CrossRef]

, 14

14. V. I. Kopp and A. Z. Genack, “Twist defect in chiral photonic structures,” Phys. Rev. Lett. 89, 033901 (2002). [CrossRef] [PubMed]

, 19

19. F. Wang and A. Lakhtakia, “Complete exhibition of defect-mode resonance despite dissipation in structurally chiral materials,” Phys. Rev. B 83, 075115 (2011). [CrossRef]

].

Fig. 5 Same as Fig. 4, except for the device labeled as RHF (Ω = 400 nm).

Were the chalcogenide glass endowed with nondispersive properties in the chosen spectral regime, the TRR spike of RHF would have been centered at λ0 = 1225 × (800/700) = 1400 nm. The fact that it is actually centered at λ0 = 1445 nm indicates that the chiral STF is optically denser at wavelengths around 1450 nm than around 1230 nm. A similar feature is evident in Fig. 3 of [8

8. R. J. Martín-Palma, J. V. Ryan, and C. G. Pantano, “Spectral behavior of the optical constants in the visible/NIR of GeSbSe chalcogenide thin films grown at glancing angle,” J. Vac. Sci. Technol. A 25, 587–591 (2007). [CrossRef]

], though either at somewhat shorter wavelengths or smaller χv. Dispersion is always accompanied by dissipation—by virtue of the principle of causality [26

26. B. Y.-K. Hu, “Kramers–Kronig in two lines,” Am. J. Phys. 57, 821 (1989). [CrossRef]

]—which would depress the peak of TRR in the spike.

5. Concluding remarks

We have shown experimentally that chiral STFs with quite a small number (16) of structural periods and made of chalcogenide glass can function adequately as wideband-rejection filters for circularly polarized radiation in the IR-A spectral regime. We also successfully fabricated a reflection-hole filter for operation near the short-wavelength edge of the IR-B spectral regime. Both types of filters are relevant to spectroscopic measurements of optical activity [27

27. Yu. N. Chirgadze, S. Yu. Venyaminov, and V. M. Lobachev, “Optical rotatory dispersion of polypeptides in the near-infrared region,” Biopolymers 10, 809–826 (1971). [CrossRef] [PubMed]

, 28

28. H. Xia, W. Tao, J. Wang, J. Zhang, and Q. Nie, “Sol-gel derived solid chiral materials and their optical activity,” Opt. Mater. 27, 279–283 (2004). [CrossRef]

]. Improvements in performance can be effected by the incorporation of impedance-matching layers [29

29. I. J. Hodgkinson, Q. H. Wu, M. Arnold, M. W. McCall, and A. Lakhtakia, “Chiral mirror and optical resonator designs for circularly polarized light: suppression of cross-polarized reflectances and transmittances,” Opt. Commun. 210, 201–211 (2002). [CrossRef]

].

Coverage of the entire IR-B regime would require chiral STFs of up to 1600-nm structural period without possibly some increase in the number of structural periods, which was not feasible with our experimental vacuum chamber but should be easily possible in the larger vacuum chambers commonly employed in the thin-film industry. Post-deposition wet etching [30

30. R. Dror, B. Sfez, Sh. Y. Goldin, and A. Cashingad, “Etching of photosensitive chalcogenide glasses: experiments and simulations,” Opt. Express 15, 12539–12547 (2007). [CrossRef] [PubMed]

] could be used to tune the spectral characteristics of chiral STFs [31

31. S. M. Pursel, M. W. Horn, and A. Lakhtakia, “Tuning of sculptured-thin-film spectral-hole filters by postdeposition etching,” Opt. Eng. 46, 040507 (2007). [CrossRef]

].

The foregoing developments strongly suggest that many different types of optical devices—such as polarizers, rugate filters, and waveplates—for use in the IR-A and IR-B spectral regimes can be made of chalcogenide glass with STF technology (Chap. 10 of [7

7. A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]

]). As this technology employs thermal evaporation, a workhorse of the thin-film industry [32

32. D. M. Mattox, The Foundations of Vacuum Coating Technology (Noyes Publications, 2003).

], the shortage of optical devices in the 1000-to-3000-nm wavelength range can be considerably alleviated. Furthermore, the photochromic properties of chalcogenide glass also promise active tunability of these devices, and their porosity suggests [33

33. A. Lakhtakia, M. W. McCall, J. A. Sherwin, Q. H. Wu, and I. J. Hodgkinson, “Sculptured-thin-film spectral holes for optical sensing of fluids,” Opt. Commun. 194, 33–46 (2001). [CrossRef]

, 34

34. T. G. Mackay and A. Lakhtakia, “Empirical model of optical sensing via spectral shift of circular Bragg phenomenon,” IEEE Photon. J. 2, 92–101 (2010). [CrossRef]

] their ability to function as infrared sensors of fluids. The emerging technology of interactive video, where both visible and infrared signals are used to track and image the users through transparent displays, could also benefit from such optical filters.

Acknowledgments

We thank anonymous reviewers for helpful suggestions, and we are grateful for technical assistance from Josh Stapleton of the Materials Research Institute, Pennsylvania State University, specially regarding the correct use of radiation blockers. AL thanks the Charles Godfrey Binder Endowment at Penn State for ongoing support of his research activities.

References and links

1.

J. A. Savage and S. Nielsen, “Chalcogenide glasses transmitting in the infrared between 1 and 20 μ — A state of the art review,” Infrared Phys. 195, 195–204 (1965). [CrossRef]

2.

A. Zakery and S. R. Elliott, “Optical properties and applications of chalcogenide glasses: a review,” J. Non-Cryst. Solids 330, 1–12 (2003). [CrossRef]

3.

K. Tanaka and K. Shimakawa, “Chalcogenide glasses in Japan: A review on photoinduced phenomena,” Phys. Status Solidi B 246, 1744–1757 (2009). [CrossRef]

4.

A. R. Hilton Sr., Chalcogenide Glasses for Infrared Optics (McGraw–Hill, 2010).

5.

A. Saha, K. Bhattacharya, and A. K. Chakraborty, “Reconfigurable achromatic half-wave and quarter-wave retarder in near infrared using crystalline quartz plates,” Opt. Eng. 50, 034004 (2011). [CrossRef]

6.

A. Lakhtakia and M. W. McCall, “Circular polarization filters,” in Encyclopedia of Optical Engineering, R. G. Driggers, ed. (Marcel Dekker, 2003), pp. 230–236.

7.

A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]

8.

R. J. Martín-Palma, J. V. Ryan, and C. G. Pantano, “Spectral behavior of the optical constants in the visible/NIR of GeSbSe chalcogenide thin films grown at glancing angle,” J. Vac. Sci. Technol. A 25, 587–591 (2007). [CrossRef]

9.

R. J. Martín-Palma, F. Zhang, A. Lakhtakia, A. Cheng, J. Xu, and C. G. Pantano, “Retardance of chalcogenide thin films grown by the oblique-angle-deposition technique,” Thin Solid Films 517, 5553–5556 (2009). [CrossRef]

10.

H. C. Chen, Theory of Electromagnetic Waves: A Coordinate-free Approach (McGraw–Hill, 1983).

11.

Q. Wu, I. J. Hodgkinson, and A. Lakhtakia, “Circular polarization filters made of chiral sculptured thin films: experimental and simulation results,” Opt. Eng. 39, 1863–1868 (2000). [CrossRef]

12.

A. Lakhtakia, “Generation of spectral holes by inserting central structurally chiral layer defects in periodic structurally chiral materials,” Opt. Commun. 275, 283–287 (2007). [CrossRef]

13.

I. J. Hodgkinson, Q. H. Wu, K. E. Thorn, A. Lakhtakia, and M. W. McCall, “Spacerless circular-polarization spectral-hole filters using chiral sculptured thin films: theory and experiment,” Opt. Commun. 184, 57–66 (2000). [CrossRef]

14.

V. I. Kopp and A. Z. Genack, “Twist defect in chiral photonic structures,” Phys. Rev. Lett. 89, 033901 (2002). [CrossRef] [PubMed]

15.

J. Schmidtke and W. Stille, “Photonic defect modes in cholesteric liquid crystal films,” Eur. Phys. J. E 12, 553–564 (2003). [CrossRef]

16.

J. A. Sherwin, A. Lakhtakia, and I. J. Hodgkinson, “On calibration of a nominal structure-property relationship model for chiral sculptured thin films by axial transmittance measurements,” Opt. Commun. 2009, 369–375 (2002). [CrossRef]

17.

J. B. Geddes III and A. Lakhtakia, “Quantification of optical pulsed-plane-wave-shaping by chiral sculptured thin films,” J. Mod. Opt. 53, 2763–2783 (2006). [CrossRef]

18.

F. Wang and A. Lakhtakia, “Specular and nonspecular, thickness-dependent, spectral holes in a slanted chiral sculptured thin film with a central twist defect,” Opt. Commun. 215, 79–92 (2003). [CrossRef]

19.

F. Wang and A. Lakhtakia, “Complete exhibition of defect-mode resonance despite dissipation in structurally chiral materials,” Phys. Rev. B 83, 075115 (2011). [CrossRef]

20.

R. Messier, T. Gehrke, C. Frankel, V. C. Venugopal, W. Otaño, and A. Lakhtakia, “Engineered sculptured nematic thin films,” J. Vac. Sci. Technol. A 15, 2148–2152 (1997). [CrossRef]

21.

I. J. Hodgkinson, Q. H. Wu, and J. Hazel, “Empirical equations for the principal refractive indices and column angle of obliquely deposited films of tantalum oxide, titanium oxide, and zirconium oxide,” Appl. Opt. 37, 2653–2659 (1998). [CrossRef]

22.

I. Hodgkinson and Q. H. Wu, “Vacuum deposited biaxial thin films with all principal axes inclined to the substrate,” J. Vac. Sci. Technol. A 17, 2928–2932 (1999). [CrossRef]

23.

I. Hodgkinson and Q. H. Wu, “Serial bideposition of anisotropic thin films with enhanced linear birefringence,” Appl. Opt. 38, 3621–3625 (1999). [CrossRef]

24.

I. Hodgkinson, Q. H. Wu, B. Knight, A. Lakhtakia, and K. Robbie, “Vacuum deposition of chiral sculptured thin films with high optical activity,” Appl. Opt. 39, 642–649 (2000). [CrossRef]

25.

S. Pursel and M. W. Horn, “Prospects for nanowire sculptured-thin-film devices,” J. Vac. Sci. Technol. B 25, 2611–2615 (2007). [CrossRef]

26.

B. Y.-K. Hu, “Kramers–Kronig in two lines,” Am. J. Phys. 57, 821 (1989). [CrossRef]

27.

Yu. N. Chirgadze, S. Yu. Venyaminov, and V. M. Lobachev, “Optical rotatory dispersion of polypeptides in the near-infrared region,” Biopolymers 10, 809–826 (1971). [CrossRef] [PubMed]

28.

H. Xia, W. Tao, J. Wang, J. Zhang, and Q. Nie, “Sol-gel derived solid chiral materials and their optical activity,” Opt. Mater. 27, 279–283 (2004). [CrossRef]

29.

I. J. Hodgkinson, Q. H. Wu, M. Arnold, M. W. McCall, and A. Lakhtakia, “Chiral mirror and optical resonator designs for circularly polarized light: suppression of cross-polarized reflectances and transmittances,” Opt. Commun. 210, 201–211 (2002). [CrossRef]

30.

R. Dror, B. Sfez, Sh. Y. Goldin, and A. Cashingad, “Etching of photosensitive chalcogenide glasses: experiments and simulations,” Opt. Express 15, 12539–12547 (2007). [CrossRef] [PubMed]

31.

S. M. Pursel, M. W. Horn, and A. Lakhtakia, “Tuning of sculptured-thin-film spectral-hole filters by postdeposition etching,” Opt. Eng. 46, 040507 (2007). [CrossRef]

32.

D. M. Mattox, The Foundations of Vacuum Coating Technology (Noyes Publications, 2003).

33.

A. Lakhtakia, M. W. McCall, J. A. Sherwin, Q. H. Wu, and I. J. Hodgkinson, “Sculptured-thin-film spectral holes for optical sensing of fluids,” Opt. Commun. 194, 33–46 (2001). [CrossRef]

34.

T. G. Mackay and A. Lakhtakia, “Empirical model of optical sensing via spectral shift of circular Bragg phenomenon,” IEEE Photon. J. 2, 92–101 (2010). [CrossRef]

OCIS Codes
(130.3060) Integrated optics : Infrared
(160.1245) Materials : Artificially engineered materials
(310.6845) Thin films : Thin film devices and applications

ToC Category:
IR Materials

History
Original Manuscript: September 15, 2011
Revised Manuscript: October 16, 2011
Manuscript Accepted: October 17, 2011
Published: October 21, 2011

Citation
Drew P. Pulsifer, Raúl J. Martín-Palma, Stephen E. Swiontek, Carlo G. Pantano, and Akhlesh Lakhtakia, "Wideband-rejection filters and reflection-hole filters of chalcogenide glass for circularly polarized IR-A and IR-B radiation," Opt. Mater. Express 1, 1332-1340 (2011)
http://www.opticsinfobase.org/ome/abstract.cfm?URI=ome-1-7-1332


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. J. A. Savage and S. Nielsen, “Chalcogenide glasses transmitting in the infrared between 1 and 20 μ — A state of the art review,” Infrared Phys.195, 195–204 (1965). [CrossRef]
  2. A. Zakery and S. R. Elliott, “Optical properties and applications of chalcogenide glasses: a review,” J. Non-Cryst. Solids330, 1–12 (2003). [CrossRef]
  3. K. Tanaka and K. Shimakawa, “Chalcogenide glasses in Japan: A review on photoinduced phenomena,” Phys. Status Solidi B246, 1744–1757 (2009). [CrossRef]
  4. A. R. Hilton, Chalcogenide Glasses for Infrared Optics (McGraw–Hill, 2010).
  5. A. Saha, K. Bhattacharya, and A. K. Chakraborty, “Reconfigurable achromatic half-wave and quarter-wave retarder in near infrared using crystalline quartz plates,” Opt. Eng.50, 034004 (2011). [CrossRef]
  6. A. Lakhtakia and M. W. McCall, “Circular polarization filters,” in Encyclopedia of Optical Engineering, R. G. Driggers, ed. (Marcel Dekker, 2003), pp. 230–236.
  7. A. Lakhtakia and R. Messier, Sculptured Thin Films: Nanoengineered Morphology and Optics (SPIE Press, 2005). [CrossRef]
  8. R. J. Martín-Palma, J. V. Ryan, and C. G. Pantano, “Spectral behavior of the optical constants in the visible/NIR of GeSbSe chalcogenide thin films grown at glancing angle,” J. Vac. Sci. Technol. A25, 587–591 (2007). [CrossRef]
  9. R. J. Martín-Palma, F. Zhang, A. Lakhtakia, A. Cheng, J. Xu, and C. G. Pantano, “Retardance of chalcogenide thin films grown by the oblique-angle-deposition technique,” Thin Solid Films517, 5553–5556 (2009). [CrossRef]
  10. H. C. Chen, Theory of Electromagnetic Waves: A Coordinate-free Approach (McGraw–Hill, 1983).
  11. Q. Wu, I. J. Hodgkinson, and A. Lakhtakia, “Circular polarization filters made of chiral sculptured thin films: experimental and simulation results,” Opt. Eng.39, 1863–1868 (2000). [CrossRef]
  12. A. Lakhtakia, “Generation of spectral holes by inserting central structurally chiral layer defects in periodic structurally chiral materials,” Opt. Commun.275, 283–287 (2007). [CrossRef]
  13. I. J. Hodgkinson, Q. H. Wu, K. E. Thorn, A. Lakhtakia, and M. W. McCall, “Spacerless circular-polarization spectral-hole filters using chiral sculptured thin films: theory and experiment,” Opt. Commun.184, 57–66 (2000). [CrossRef]
  14. V. I. Kopp and A. Z. Genack, “Twist defect in chiral photonic structures,” Phys. Rev. Lett.89, 033901 (2002). [CrossRef] [PubMed]
  15. J. Schmidtke and W. Stille, “Photonic defect modes in cholesteric liquid crystal films,” Eur. Phys. J. E12, 553–564 (2003). [CrossRef]
  16. J. A. Sherwin, A. Lakhtakia, and I. J. Hodgkinson, “On calibration of a nominal structure-property relationship model for chiral sculptured thin films by axial transmittance measurements,” Opt. Commun.2009, 369–375 (2002). [CrossRef]
  17. J. B. Geddes and A. Lakhtakia, “Quantification of optical pulsed-plane-wave-shaping by chiral sculptured thin films,” J. Mod. Opt.53, 2763–2783 (2006). [CrossRef]
  18. F. Wang and A. Lakhtakia, “Specular and nonspecular, thickness-dependent, spectral holes in a slanted chiral sculptured thin film with a central twist defect,” Opt. Commun.215, 79–92 (2003). [CrossRef]
  19. F. Wang and A. Lakhtakia, “Complete exhibition of defect-mode resonance despite dissipation in structurally chiral materials,” Phys. Rev. B83, 075115 (2011). [CrossRef]
  20. R. Messier, T. Gehrke, C. Frankel, V. C. Venugopal, W. Otaño, and A. Lakhtakia, “Engineered sculptured nematic thin films,” J. Vac. Sci. Technol. A15, 2148–2152 (1997). [CrossRef]
  21. I. J. Hodgkinson, Q. H. Wu, and J. Hazel, “Empirical equations for the principal refractive indices and column angle of obliquely deposited films of tantalum oxide, titanium oxide, and zirconium oxide,” Appl. Opt.37, 2653–2659 (1998). [CrossRef]
  22. I. Hodgkinson and Q. H. Wu, “Vacuum deposited biaxial thin films with all principal axes inclined to the substrate,” J. Vac. Sci. Technol. A17, 2928–2932 (1999). [CrossRef]
  23. I. Hodgkinson and Q. H. Wu, “Serial bideposition of anisotropic thin films with enhanced linear birefringence,” Appl. Opt.38, 3621–3625 (1999). [CrossRef]
  24. I. Hodgkinson, Q. H. Wu, B. Knight, A. Lakhtakia, and K. Robbie, “Vacuum deposition of chiral sculptured thin films with high optical activity,” Appl. Opt.39, 642–649 (2000). [CrossRef]
  25. S. Pursel and M. W. Horn, “Prospects for nanowire sculptured-thin-film devices,” J. Vac. Sci. Technol. B25, 2611–2615 (2007). [CrossRef]
  26. B. Y.-K. Hu, “Kramers–Kronig in two lines,” Am. J. Phys.57, 821 (1989). [CrossRef]
  27. Yu. N. Chirgadze, S. Yu. Venyaminov, and V. M. Lobachev, “Optical rotatory dispersion of polypeptides in the near-infrared region,” Biopolymers10, 809–826 (1971). [CrossRef] [PubMed]
  28. H. Xia, W. Tao, J. Wang, J. Zhang, and Q. Nie, “Sol-gel derived solid chiral materials and their optical activity,” Opt. Mater.27, 279–283 (2004). [CrossRef]
  29. I. J. Hodgkinson, Q. H. Wu, M. Arnold, M. W. McCall, and A. Lakhtakia, “Chiral mirror and optical resonator designs for circularly polarized light: suppression of cross-polarized reflectances and transmittances,” Opt. Commun.210, 201–211 (2002). [CrossRef]
  30. R. Dror, B. Sfez, Sh. Y. Goldin, and A. Cashingad, “Etching of photosensitive chalcogenide glasses: experiments and simulations,” Opt. Express15, 12539–12547 (2007). [CrossRef] [PubMed]
  31. S. M. Pursel, M. W. Horn, and A. Lakhtakia, “Tuning of sculptured-thin-film spectral-hole filters by postdeposition etching,” Opt. Eng.46, 040507 (2007). [CrossRef]
  32. D. M. Mattox, The Foundations of Vacuum Coating Technology (Noyes Publications, 2003).
  33. A. Lakhtakia, M. W. McCall, J. A. Sherwin, Q. H. Wu, and I. J. Hodgkinson, “Sculptured-thin-film spectral holes for optical sensing of fluids,” Opt. Commun.194, 33–46 (2001). [CrossRef]
  34. T. G. Mackay and A. Lakhtakia, “Empirical model of optical sensing via spectral shift of circular Bragg phenomenon,” IEEE Photon. J.2, 92–101 (2010). [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.

Figures

Fig. 1 Fig. 2 Fig. 3
 
Fig. 4 Fig. 5
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited