• Laser Solutions
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• v.15 no.2
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• pp.6-10
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• 2012

We fabricated the diffraction grating on the surface of fused silica glass using a femtosecond laser. The grooves of diffraction grating has a lot of micro crack and debris result in reduced diffraction efficiency. So, we polished the diffraction grating with $CO_2$ laser beam. With different scan number of $CO_2$ laser beam, we observed the image of diffraction grating and measured the diffraction efficiency.

• Current Optics and Photonics
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• v.2 no.2
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• pp.125-133
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• 2018

We report an in-depth analysis of the design and fabrication of multilayer dielectric (MLD) diffraction gratings for spectral beam combining at a wavelength of 1055 nm. The design involves a near-Littrow grating and a modal analysis for high diffraction efficiency. A range of wavelengths, grating periods, and angles of incidence were examined for the near-Littrow grating, for the $0^{th}$ and $-1^{st}$ diffraction orders only. A modal method was then used to investigate the effect of the duty cycle on the effective indices of the grating modes, and the depth of the grating was determined for only the $-1^{st}$-order diffraction. The design parameters of the grating and the matching layer thickness between grating and MLD reflector were refined for high diffraction efficiency, using the finite-difference time-domain (FDTD) method. A high reflector was deposited by electron-beam evaporation, and a grating structure was fabricated by photolithography and reactive-ion etching. The diffraction efficiency and laser-induced damage threshold of the fabricated MLD diffraction gratings were measured, and the diffraction efficiency was compared with the design's value.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.260-266
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• 2022

A diffraction grating structure composed of two matching layers and two grating layers was formed, and a diffraction grating with high transmission diffraction efficiency in the -1st order was designed through an optimization technique. The designed diffraction grating had a transverse electric wave diffraction efficiency of 99.997% at the design center wavelength, and had a wavelength width of 80 nm and an incident angle width of 20.0° that maintained a diffraction efficiency of 95% or more. By performing the grating tolerance analysis, it was confirmed that the thickness tolerance for a diffraction efficiency of 95% or more was secured to at least 60 nm, and the diffraction efficiency could be maintained even in a trapezoidal shape with an internal angle of less than 10°.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1428-1429
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• 2006

We investigated the diffraction efficiency, erasing property and rewriting property of diffraction grating with each wavelength of recording beam. A (P:P) polarized light was exposed on AsGeSeS and Ag/AsGeSeS thin film to form a diffraction grating by HeNe(635nm) laser and DPSS(532nm) laser. At the maximum efficiency condition, unpolarized HeNe laser beam was irradiated to erase 1ha generated diffraction grating. The HeNe laser showed more higher diffraction efficiency and the DPSS laser showed more faster diffraction grating time. At erasing and rewriting process, AsGeSeS(61%-85%)thin film showed better property than Ag doped Ag/AsGeSeS(53%-63%) double layer structured thin film.

• Korean Journal of Optics and Photonics
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• v.33 no.1
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• pp.22-27
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• 2022

We fabricate a polarization-independent dielectric multilayer thin-film diffraction grating for a spectral-beam-combining (SBC) system with a simple grating structure and low aspect ratio. Due to the refractive index and thickness error of the manufactured thin films, the diffraction efficiency of the fabricated diffraction grating was lower than that of the design. The causes of the errors were analyzed, and it was confirmed through simulation that diffraction efficiency could be compensated through an additional coating on the manufactured diffraction grating. As a result of sputtering an additional Ta₂O₅ layer on a fabricated diffraction grating, the diffraction efficiency was corrected and a maximum 91.7% of polarization-independent diffraction efficiency was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1058-1061
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• 2003

In this thesis, we observed the optical characteristic of amorphous chalcogenide thin films by He-Cd laser. Also, grating formation by He-Ne laser and He-Cd laser. After analyze diffraction efficiency of the time on the $Ag(200{\AA})/As_{40}Ge_{10}Se_{15}S_{35}$ thin films. The result diffraction efficiency of Maximun 0.2% reduced according to time grating formation by He-Ne laser. Diffraction efficiency of Maximun 0.1% showed stabiliy characteristic according to time grating formation by He-Cd laser.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.125-131
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• 1996

In this paper, we introduced the BQBPH method for making the grating of high efficiency which was improtant in implementing optical PS. The pattern of graing was obtianed by computer simulations using iterative method, and the diffraction efficeincy of designed grating was about 67% through BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency was 47%. We implemented the optical PS with the grating and showed that optical experimental output patterns were good agreement with PS output patterns and first order was main diffraction order.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.447-448
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• 2008

In this paper, we investigated the diffraction grating efficiency on AsSeS and Ag-doped amorphous chalcogenide Ag/AsSeS thin film for used to volume hologram. The film thickness was 0.5um and diffraction efficiency was obtained from (P:P) polarized He-Ne (632.8nm)laser beam on AsSeS and Ag/AsSeS thin films. As a results, diffraction grating was not formed at AsSeS thin film but at Ag-doped AsSeS thin film, diffraction grating was formed well compare with the former.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.55-56
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• 2006

We investigated the diffraction grating efficiency by the DPSS laser beam wavelength to improve the diffraction efficiency on AsGeSeS & Ag/ AsGeSeS thin film. Diffraction efficiency was obtained from DPSS(532nm)(P:P)polarized laser beam on AsGeSeS, Ag/ AsGeSeS and AsGeSeS/Ag/AsGeSeS thin films. As a result, for the laser beam intensity, 0.24 mW, single AsGeSeS thin film shows the highest value of 0.161% diffraction efficiency at 300 s and for 2.4 mW, it was recorded with the fastest speed of 50 s, which the diffraction grating forming speed is faster than that of 0.24 mW beam. Ag/ AsGeSeS and AsGeSeS/ Ag/ AsGeSeS multi-layered thin film also show the faster grating forming speed at 2.4 mW and higher value of diffraction efficiency at 0.24 mW.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.119-122
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• 2004

This paper discovers that we form holographic grating in AsGeSeS thin film. Holographic grating is not developed in the length of 10,20,40nm, while it is formed in the thin film of 80nm though it shows very low diffraction efficiency. On the contrary, holographic grating is established in every thin film of Ag(10nm)/AsGeSeS(10,20,40,80nm). Lattice in 10,20 nm thin film builds up, and immediately disappears. In the case of 40nm thin film, even if holographic grating is made up, it seems to have a low diffraction efficiency. Apart from 10,20,40nm, it shows the highest diffraction efficiency in the thin film of 80nm.