Aresenic trisulfide($As_2S_3$) thin film is deposited in vacuum by thermal evaporation process and the conjugate wave generated in the thin film by degenerate four wave mixing is investigated.
The film has ideal amorphous structure and has at room temperature the capacity of recoding fringe of several thousand line pairs/mm. The phase microscopic observations reveal the recorded fringes, and prove its high hologram recording capacity.
The phase conjugate generated wave by the degenerate four wave mixing has many important properties, particulary in the time domain. The relevant kinetics is established by taking account of the three level energy structure of the solid. Electrons are excited by the interaction with laser photon from $Ar^+$ ion laser and trapped in the intermediate level. Those trapped electrons are evacuated by the heating the specimen up to 170℃. Thus the $As_2S_3$ film can be promising writing and erazing recorder. When the film is irradiated with laser beam, the writing and erazing process can be shortened, so that the system can become to a nearly real-time image processor.
From the rate equations set up from the energy band structure, the time dependent behavior of the intensity is numerically clarified and good agreement between the theoretical values and experimental data are confirmed.
In the present experiment, the phase conjugate wave is found indeed that it is the diffracted wave of the backward beam $A_f$ and the prove beam $A_p$, and from the attenuation characteristics of the conjugate wave when A$_f$ and $A_p$ are blocked, the erazing kinetics under laser beam illumination is established.
Present investigation has proven many potential applications of $As_2S_3$ thin film. Further investigation is worth being carried out and in continued.
