Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Design and fabrication of antireflective optical elements for CO2 lasers

Document Type : Research Paper

Authors

M.H. Maleki 1
S. Jelvani 1
I. Hosseinzadeh Lich 1
H. Hojati Rad 1
M. Geshlaghi 1
H. Mallahi 2

1 Photonics and Quantum Technology Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 1339-14155, Tehran - Iran

2 Department of Physics, Faculty of Basic Sciences, Islamic Azad University Central Tehran Branch, P.O.Box: 14696691941, Tehran - Iran

https://doi.org/10.24200/nst.2021.1189
Abstract
Anti-reflective optical elements prepared on ZnSe substrates are the main optical devices in CO2 lasers. These ‎anti-reflective coatings are used in the far-infrared region at the specified wavelength of 10600 nm. For the preparation phase of these anti-reflective coatings, first, the characterization of the used materials in this wavelength was investigated and then YbF3 and ZnS were chosen. However, a lot of research work has been done in the country to make reflection mirrors of gold and silver for a wavelength of 1.6 microns, but no research has been done on anti-reflective optical window or part of it at this wavelength. Then, anti-reflective coating at 10600 nm was designed by the Macleod software using these two materials. These thin films were deposited on one side of ZnSe substrates by physical vapor deposition (PVD) method with Balzers- Ba510 coating system. Optical element operation was investigated by a 10 W CO2 laser and the transmission was measured for the standard anti-reflection, the polished substrate, and the deposited antireflective element. The results show that the prepared anti-reflective element has 77.84% transmission coefficient. By studying the morphology and thickness of the layers by SEM, it was found that the transmission coefficient of ZnSe substrate is optimized by the prepared anti-reflection element.

Highlights

1. http//www. II-VI-infrared.com/ Optical-Materials/ ZnSe/ html.

 

2. T.H.A. Macleod, Thin film Optical filters, Adam Hilger Ltd (1986).

 

3. B.S. Patel, Optical suitability of window materials for CO2 lasers, Applied Optics, 16(5), 1232-1235 (1997).

 

4. R.R. Phillips, et al, Simple method for antireflection Coating ZnSe in the 20 µm wavelength range, Applied Optics, 47(7), 870-873 (2008).

 

5. Y. Zhang, et al, Determination of infrared refractive index of ZnS and YbF3 thin films by spectroscopy, Optik, 170, 321-327 (2018).

 

6. T. Amotchkina, et al, Characterization of e-beam evaporated Ge, YbF3, ZnS, and LaF3 thin films for laser-oriented coatings, Applied Optics, 59, Issue 5, A40-A47 (2020).

 

7. B. Ucer, Design and Production of Anti reflection Coating For Ge, ZnSe And ZnS In 8-12 µm Wavelength region, A thesis submitted to the Graduate School of natural and applied sciences of the middle east technical university (2009).

 

8. D. Cohen, et al, Dual and triple band AR coatings for IR systems, Proc. SPIE 8704, Infrared Technology and Applications XXXIX, 870422 (June 18, 2013).

 

9. Y. Pan, et al, Design and fabrication of ultra-broadband infrared antireflection hard coatings on ZnSe in the range from 2 to 16 μm, Infrared Physics & Technology, 52, 193–195 (2009).

 

10. M. Gheshlaghi, et al, Coating optimization of 50w medical CO2 laser metal mirrors using substitute materials of Au, Annual Physics Conference of Iran, 2009 (in Persian).

Keywords

Antireflective optical element
ZnSe substrate
YbF3
ZnS
Coating
CO2 laser
1. http//www. II-VI-infrared.com/ Optical-Materials/ ZnSe/ html.
 
2. T.H.A. Macleod, Thin film Optical filters, Adam Hilger Ltd (1986).
 
3. B.S. Patel, Optical suitability of window materials for CO2 lasers, Applied Optics, 16(5), 1232-1235 (1997).
 
4. R.R. Phillips, et al, Simple method for antireflection Coating ZnSe in the 20 µm wavelength range, Applied Optics, 47(7), 870-873 (2008).
 
5. Y. Zhang, et al, Determination of infrared refractive index of ZnS and YbF3 thin films by spectroscopy, Optik, 170, 321-327 (2018).
 
6. T. Amotchkina, et al, Characterization of e-beam evaporated Ge, YbF3, ZnS, and LaF3 thin films for laser-oriented coatings, Applied Optics, 59, Issue 5, A40-A47 (2020).
 
7. B. Ucer, Design and Production of Anti reflection Coating For Ge, ZnSe And ZnS In 8-12 µm Wavelength region, A thesis submitted to the Graduate School of natural and applied sciences of the middle east technical university (2009).
 
8. D. Cohen, et al, Dual and triple band AR coatings for IR systems, Proc. SPIE 8704, Infrared Technology and Applications XXXIX, 870422 (June 18, 2013).
 
9. Y. Pan, et al, Design and fabrication of ultra-broadband infrared antireflection hard coatings on ZnSe in the range from 2 to 16 μm, Infrared Physics & Technology, 52, 193–195 (2009).
 
10. M. Gheshlaghi, et al, Coating optimization of 50w medical CO2 laser metal mirrors using substitute materials of Au, Annual Physics Conference of Iran, 2009 (in Persian).

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