• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.456-459
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• 2003

In this thesis, We observed the characteristic of the diffraction efficiency according to the wave length of the chalcogenide thin films. The used an $Ag(200{\AA})/As_{40}Ge_{10}Se_{15}S_{35}$ thin film. We made grating formation by each wave length 325nm, 442nm, 632.8nm. After measure diffraction efficiency of the time. We expressed the maxium saturation value at fast time as were the short wavelength and stable characteristic. On the other hand we appeard to the by a maxium diffraction efficiency the 1.7% in 325nm, 0.8% in 442nm, 0.27% in 632.8nm. The maximum diffraction efficiency expressed high value as were the long wavelength.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.791-795
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• 2000

Amorphous chalcogenide glasses have a wide variety of light-induced effects. In this study, we have investigated the diffraction efficiency of chalcogenide. As$_{40}$ Ge$_{10}$ Se$_{15}$ S$_{35}$ thin films by the various applied electric fields. The holographic grating in these thin films has been formed using a linearly polarized He-Ne laser light (633nm). The diffraction efficiency was investigated the two method of applied electric field in the perpendicular and parallel to the direction of inducing beam. We obtained that properties of diffraction efficiency in the two methods of applied electric field. The result is shown that the diffraction efficiency of parallel electric field is 285% increase, η=1.1$\times$10$^{-3}$ and the diffraction efficiency of perpendicular electric field is 80% decrease, η=9.83$\times$10$^{-5}$ . Also, we have investigated the anisotropy property on chalcogenide thin films by the electric field effects.

• 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.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.213-217
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• 2012

In this study, we have investigated the holographic grating formation on Ag-doped amorphous As-Ge-Se-S thin films. The dependence of diffraction efficiency as afunction of Ag layer thickness has been investigated in this amorphous chalcogenide films. Holographic gratings was formed using [P:P] polarized Diode Pumped Solid State laser (DPSS, 532.0 nm). The diffraction efficiency was obtained by +1st order intensity. The results were shown that the diffraction efficiency of Ag/AsGeSeS double layer thin films for the Ag thickness, the maximum grating diffraction efficiency using 60 nm Ag layer is 0.96%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1029-1032
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• 2004

This paper investigates that how diffraction efficiency is going to change according to amorphous As-Ge-Se-S. We made films such as $\lambda$, $\lambda/2$, $\lambda/4$, $\lambda/8$ on the basis of 633nm, which is wavelength of recording laser(He-Ne). Among them, $\lambda/4$ has the highest diffraction efficiency value, while $\lambda/8$ has the lowest. The experiment shows that the highest diffraction efficiency value of $\lambda/4$ is about 0.09%, whereas diffraction efficiency of $\lambda/8$ is formed, which is merely close to 0%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.490-493
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• 2003

We have carried out two-beam interference experiment to form holographic grating on amorphous $As_{40}Ge_{10}Se_{15}S_{35}/Ag$ double-layer. In this study holographic grating formed using He-Ne laser(632.8nm) under non-polarization state and p-polarization state and we confirm that the diffraction efficiency depend on thickness of Ag. The diffraction efficiency was obtained by first order intensity. We got the maximum diffraction efficiency that thickness of Ag was $600{\AA}$. The maximum diffraction efficiency was 13.5% in (P:P) polarization state.

• 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 Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.91-94
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• 1988

This paper is investigated on the diffraction grating formation of the amorphous As-Se-S-Ge films. AS$\_$40/Se$\_$15/S$\_$36/Ge$\_$10/ film of thickness 0.76 $\mu\textrm{m}$ has achieved a high diffraction efficiency of 4.6%. In this film, high diffraction efficiency is increased to 18% by chemical etching.

• 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.