| SM ISO690:2012|
NASTAS, Andrian; IOVU, Mihail. Selection of center carrier frequency for holographic recording on the photothermoplastic registration structure based on chalcogenide vitreous semiconductors. In: Materials Science and Condensed Matter Physics. Editia a 8-a, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, p. 259. ISBN 978-9975-9787-1-2.
|Materials Science and Condensed Matter Physics
Editia a 8-a, 2016
Conferința "International Conference on Materials Science and Condensed Matter Physics" |
8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016
In our days besides the traditional holographic methods of registration of optical information, the new holographic methods became more attractive due to rapid development of new electronic methods of registration and processing of optical images, For example, such methods as 3D digital holographic microscopy and holographic recording under influence of corona discharge can be mentioned, In the latter case the enhancing of sensitivity and diffraction efficiency (η) of gratings can be achieved. For fabrication of diffractive optical elements, the amorphous thin film structures are more promising sensitive recording media with high resolution . A special interests in the holographic recording process is attributed to the methods which provide enhancement of the recording resolution and image quality. The aim of the present paper consists in determination both of the optimal spatial frequency (f) for holographic recording of the gratings and of the center carrier frequency for recording of hologram with the pit structure of deformation on the photothermoplastic registration structure (PTPS), based on chalcogenide vitreous semiconductors (ChGS). The methodology of preparation and investigation of samples are described in . In this paper, we studied holographic gratings obtained on the surface of a two-layer photothermoplastic carrier (PTPC) by the holographic method of simultaneous photothermoplastic recording. As a PTPC, we used a multilayer system consisting of a polymeric (polyethylene terephthalate) substrate, a metal (chromium) electrode, a photosensitive semiconductor (0.5(As2S3)0.5(As2Se3)), and a thermoplastic layer (BMA-50). For these samples, we determined the η, For these two samples the contrast of the holographic image K, signal to noise ratio SNR, width half Δf in the dependence η(f) were measured. The parameters of the images produced by the patterns recorded with the frequency f=300 mm-1 on the structures PTPS with different thickness of thermoplastic layer are presented below in the Table 1. For the used registration structure and conditions of holographic recording, the frequency f=300 mm-1 is the resonance one for the thermoplastic thickness d of 1,3 μm. For the thermoplastic layer with the thickness of 1 μm this frequency corresponds to the frequency of the neighboring peak with the resonance peak in the dependence η(f) For these two samples the contrast of the holographic image K, signal to noise ratio SNR, diffraction efficiency η and the width half Δf in the dependence η(f) were measured. d, mkm frec., mm-1 frez., mm-1 SNR η, % К Δf, mm-1 1 300 450 200 2,25 0,99 1001,3 300 300 20 0,25 0,91 50 Table 1. Parameters of the holographic images produced by the patterns recorded with the spatial frequency f=300 mm-1 in the PTPS with the thermoplastic layer thickness of 1 and 1.3 μ m. In order to improve the quality of the holographic image it is necessary to carry out the holographic registration at the center carrier frequency of values 1.5-2 times lower than the resonance frequency.