| Title |
The Formation of Holographic Data Grating on Amorphous Chalcogenide Ag/As_{40}Ge_{10}Se_{15}S_{35} Thin Films with Various Thickness |
| Authors |
여철호(Yea, Chul-Ho) ; 정홍배(Chung, Hong-Bay) |
| Keywords |
Chalcogenide Thin Film ; Polarization Holographic Data Grating ; Diffraction Efficiency ; Q Factor |
| Abstract |
The Ag photodoping effect in amorphous As_{40}Ge_{10}Se_{15}S_{35} chalcogenide thin films for holographic recording has been investigated using a He-Ne laser ({Λ}=632.8 nm). The chalcogenide films thickness prepared in the present work were thinner in comparison with the penetration depth of recording light (d_p=1.66μm). It exhibits a tendency of the variation of the diffraction efficiency (η) in amorphous chalcogende films, independently of the Ag photodoping. That is, η increases rapidly at the beginning of the recording process and reaches the maximum (η_{max}) and slowly decreases slowly with the exposed time. In addition, the value of η_{max} depends strongly on chalcogenide film thickness(d) and its maximum peak among the films with d = 40, 80, 150, 300, and 633 nm is observed 0.083% at d = 150 nm (approximately 1/2 δn), where δn is the refractive index of chalcogenide thin film (δn=2.0). The η is largely enhanced by Ag photodoping into the chakogenides. In particular, the value of η_{max} in a bilayer of 10-nm-thick Ag/150-nm-thick As_{40}Ge_{10}Se_{15}S_{35} film is about 1.6%, which corresponds to ~20 times larger than that of the single-layer As_{40}Ge_{10}Se_{15}S_{35} thin film (without Ag). And we obtained the diffraction pattern according to the formation of (P:P) polarization holographic grating using Mask pattern and SLM. |