Center of Excellence for Innovative Technologies
and NanoEngineering (CE ITNE)

National Budget/Modulator (from the Ministry of Education and Science of Ukraine)

Name

Development of a new generation of high-performance acousto-optical modulators on standing acoustic waves

Project content

Task of project:

The main problem to be solved in the proposed project is the number of fundamental disadvantages of existing AO modulators, namely, the high attenuation of acoustic waves at frequencies of ~ 1 GHz and above, the low AO quality factors and, accordingly, the large control powers of ~ 10 W, the high temperature instability of modulators and their low radiation resistance. Therefore, the search for effective acousto-optical materials with high acousto-optical efficiency and, accordingly, low power of control electrical signals, low acoustic wave attenuation and high radiation resistance to high-power laser radiation is a topical modern task.

Object and subject of research:

The object of the project research is high-quality crystals of lithium tetraborate (Li2B4O7) and calcium tungstate (CaWO4), which can be devoid of the disadvantages listed in paragraph 1.1. It is also planned to consider the modern materials with a periodic change of refractive index in the volume of the sample (change period is 30-50 ?m) with a high AO efficiency. The subject of the research project is induced optical and quasi-optical effects of the selected materials, the spatial anisotropy of these effects and the characteristics of effective light and the sound conductors (AO-cells) made of these materials.

The purpose and main objectives of the study:

The main goal of the project is to develop a new generation of acousto-optical modulators with high performance characteristics, such as: 1) low power consumption ~ 0.1 W, 2) high temperature stability without the use of thermal stabilization, 3) high radiation resistance ~ 30 GW / cm2 (for high-power optical beam modulation), 4) high operating frequencies of modulators (16 GHz). To achieve this goal it is necessary to perform the following tasks: 1) selecting effective acousto-optical materials that satisfy the specified performance characteristics; 2) for the selected materials, to measure all the parameters necessary to check their performance and establishment of the maximum AO efficiency; 3) to find the geometries with maximum photoelastic and acousto-optical interaction by the method of pointing or extreme surfaces developed by the authors of the project; 4) to make a light- and soundconductors(AO-cells) of optimized geometry from the selected materials and to confirm experimentally their high acousto-optical efficiency and accordance to the specified performance characteristics.

The main results

  1. The setups for experimental measurements of necessary parameters in crystals of various classes symmetry were modernized, namely: 1) the interferometric setup, 2) the setup according to the Dixon-Cowan scheme, 3) the setup for measurement of acoustic wave speed. The samples of selected acousto-optical materials were made, namely: CBC, HCGS; AO cells made of CaWO4 were also made.
  2. Matrices of piezo- and elastic-optical coefficients of selected crystals Li2B4O7, TGS-TGS + Cr, glass-ceramic HGGS-composite are filled, diffraction photoelasticity of LHS crystals is investigated, 3D analysis of anisotropy of photoelasticity effects is carried out.
  3. On the basis of the investigated effective acousto-optical crystals of calcium tungstate and lithium tetraborate laboratory models of light and sound conductors are made. Positive results of their test tests are received.

Originality and innovative aspects

According to the project materials the oral and poster presentations were made at international conferences:

Publications

Within the project the scientific and technical papers were published:

  1. Buryy O., Andrushchak N., Ratych A., Demyanyshyn N., Mytsyk B., Andru-shchak A. Global maxima for the acousto-optic effect in SrB4O7 crystals // Applied Optics. – 2017. –V. 56, No. 7. – P. 1839-1845 https://doi.org/10.1364/AO.56.001839
  2. Andrushchak A., Buryy O., Andrushchak N., Hotra Z., Sushynskyi O., Singh G., Janyani V., Kityk I. General method of extreme surfaces for geometry optimization of the linear electro-optic effect on example of LiNbO3:MgO crystal // Applied Optics.– 2017. –V. 56, No. 22. – P. 6255-6262 https://doi.org/10.1364/AO.56.006255
  3. Mytsyk B., Shpotyuk O., Demyanyshyn N., Kost Y., Calvez L., Andrushchak A. Photoelastic and acousto-optic efficiency of 65GeS2-25Ga2S3-10CsCl chalcohalide glass // Journal of Non-Crystalline Solids. – 2018. – V.481. – P. 160-163 https://doi.org/10.1016/j.jnoncrysol.2017.10.036
  4. Andrushchak A.S, Buryy O.A., Demyanyshyn N.M., Hotra Z.Yu., Mytsyk B.G. Global maxima for the acousto-optic effect in CaWO4 crystals // Acta Physica Polonica A. – 2018. – 133(4). – P. 928-932 10.12693/APhys PolA.133.928
  5. Mytsyk B., Stadnyk V., Demya¬nyshyn N., Kost Ya., and Shchepanskyi P. Photoelasticity of ammonium sulfate crystals // Optical Materials. – 2019. – V 88. – P. 723-728 10.1016/j.optmat.2018.12.005
  6. Buryy O., Andrushchak N., Demyanyshyn N., and Andrushchak A. Determination of acousto-optical effect maxima for optically isotropic crystalline material on the example of GaP cubic crystal // Journal of the Optical Society of America B . –2019. – V. 36, N8. – pp. 2023-2029. https://doi.org/10.1364/JOSAB.36.002023
  7. Mytsyk B.G., Andrushchak A.S., Vynnyk D.M., Demyanyshyn N.M., Kost Ya.P., Kityk A.V. Characterization of Photoelastic Materials by Combined Mach-Zehnder and Conoscopic Interferometry: Application to Tetragonal Lithium Tetraborate Crystals // Optics and Lasers in Engineering. – 2020. – V. 127. – pp.105991(1-8) https://doi.org/10.1016/j.optlaseng.2019.105991