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Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Vol. 42, Iss. 19 — Jul. 1, 2003
  • pp: 4045–4048

Antireflection coating formed by plasma-enhanced chemical-vapor deposition for terahertz-frequency germanium optics

Iwao Hosako  »View Author Affiliations


Applied Optics, Vol. 42, Issue 19, pp. 4045-4048 (2003)
http://dx.doi.org/10.1364/AO.42.004045


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Abstract

A method of manufacturing optical coatings for germanium optics used at terahertz frequencies has been developed. The various optical coatings used at terahertz frequencies are difficult to manufacture conventionally because these coatings must be as thick as several tens of micrometers, which is far thicker than those used in the optical region. One way to overcome this problem is to form a silicon oxide layer through plasma-enhanced chemical-vapor deposition, with silane (SiH4) as a source gas. Using this method, I formed 21-μm-thick silicon oxide films as antireflection (AR) layers for germanium optics and obtained low reflection at 1.7 THz (wavelength, λ = 175 μm). This method is easily applied to large-aperture optics and micro-optics as well as to optics with a complex surface form. The AR coatings can also be formed for photoconductive detectors made from germanium doped with gallium at a low temperature (160 °C); this low temperature ensures that the doped impurities in the germanium do not diffuse. Fabrication of optical coatings upon substrates that have refractive indices of 3.84–11.7 may also be possible by control of the refractive indices of the deposited layers.

© 2003 Optical Society of America

OCIS Codes
(260.3090) Physical optics : Infrared, far
(310.1210) Thin films : Antireflection coatings
(350.7420) Other areas of optics : Waves

History
Original Manuscript: August 26, 2002
Revised Manuscript: April 2, 2003
Published: July 1, 2003

Citation
Iwao Hosako, "Antireflection coating formed by plasma-enhanced chemical-vapor deposition for terahertz-frequency germanium optics," Appl. Opt. 42, 4045-4048 (2003)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-42-19-4045


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References

  1. D. A. DeCrosta, J. J. Hackenberg, J. H. Linn, “Characterization of high oxygen: tetraethylorthosilicate ratio plasma-enhanced chemical vapor deposition films,” J. Electrochem. Soc. 143, 1079–1084 (1996). [CrossRef]
  2. A. J. Gatesman, J. Waldman, M. Ji, C. Musante, S. Yngvesson, “An anti-reflection coating for silicon optics at terahertz frequencies,” IEEE Microwave Guided Wave Lett. 10, 264–266 (2000). [CrossRef]
  3. K. R. Armstrong, F. J. Low, “Far-infrared filters utilizing small particle scattering and antireflection coatings,” Appl. Opt. 13, 425–430 (1974). [CrossRef] [PubMed]
  4. J. Shao, J. A. Dobrowolski, “Multilayer interference filters for the far-infrared and submillimeter regions,” Appl. Opt. 32, 2361–2370 (1993). [CrossRef] [PubMed]
  5. K. Kawase, N. Hiromoto, “Terahertz-wave antireflection coating on Ge and GaAs with fused quartz,” Appl. Opt. 37, 1862–1866 (1998). [CrossRef]
  6. N. Hiromoto, M. Fijiwara, H. Shibai, H. Okuda, “Ge:Ga far-infrared photoconductors for space applications,” Jpn. J. Appl. Phys. 35, 1676–1680 (1996). [CrossRef]
  7. E. Gornik, ed., special issue on far-infrared semiconductor lasers, Opt. Quantum Electron. 23, S111–S349 (1991).
  8. H. A. Macleod, “Thin-film optical coating design,” in Thin Films for Optical Systems, F. R. Flory, ed., (Marcel Dekker, New York, 1995), pp. 1–39.
  9. E. D. Palik, ed., Handbook of Optical Constants of Solids (Academic, Orlando, Fla., 1985), pp. 465–478, 547–569, 749–763.
  10. C. M. Randall, R. D. Rawcliffe, “Refractive indices of germanium, silicon, and fused quartz in the far infrared,” Appl. Opt. 6, 1889–1895 (1967). [CrossRef] [PubMed]
  11. K. Kawase, M. Sato, T. Taniuchi, H. Ito, “Coherent tunable THz-wave generation from LiNbO3 with monolithic grating coupler,” Appl. Phys. Lett. 68, 2483–2485 (1996). [CrossRef]
  12. Q. Chen, Z. P. Jiang, M. Tani, X.-C. Zhang, “Electro-optic terahertz transceiver,” Electron. Lett. 36, 1298–1299 (2000). [CrossRef]

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