FEATURES OF MULTIPLEXED HOLOGRAMS RECORDING IN PHOTO-THERMO-REFRACTIVE GLASS

• Main Authors: S. A. Ivanov, V. B. Doan, A. I. Ignatiev, N. V. Nikonorov
• Format: Article
• Language: English
• Published: Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University) 2016-05-01
• Series: Naučno-tehničeskij Vestnik Informacionnyh Tehnologij, Mehaniki i Optiki
• Subjects: PTR glass; refractive index; optical radiation combiner; holograms; multiplexer
• Online Access: http://ntv.ifmo.ru/file/article/15501.pdf
• ISSN: 2226-1494; 2500-0373

We have carried out calculations of recording conditions for multiplexed holograms in photo-thermo-refractive (PTR) glass. The proposed calculation sets the link between such parameters as: the angle between recording beams and the angle of sample rotation, operating wavelength, the angle of incidence on the element, output angle. To study recording features of multiplexed holograms on PTR glass several elements was made. Six holograms in each element were recorded with various exposures. All samples were heat-treated at one temperature around glass transition temperature. It has been demonstrated that at the recording of several gratings with a total exposure exceeding an optimal value for a given material, the total value of the refractive index modulation amplitude (n1) reaches the maximum attainable magnitude that is equivalent to a value of a single hologram with optimal exposure. It has been found that refractive index dynamic range of the material distributes between the gratings in accordance with the ratio between exposure times if holograms exposures have significant differences. In the present paper six-channel multiplexer was recorded for a wavelength equal to 632.8 nm (He-Ne laser). The diffraction angles correspond to calculations mentioned above. The n1 value in each grating is equal to the value of the highest attainable value of the value of n1 divided by the total number of multiplexed holograms.