Development and research of holographic optical elements in Azo-polymers

Jeļena Miķelsone (ISSP UL Laboratory of Optical Recording), scientific workshop of Master’s Program course B “Topical Material and Solid State Physics Problems” of ISSP UL Doctoral School “Functional Materials and Nanotechnologies”, October 26, at 13:00, ISSP UL, Ķengaraga street 8, 2nd floor hall.

Diffractive optical elements (DOE) are used in telecommunication technologies, monochromators, electro-optical devices, various filters, art, security systems, etc., so DOE development is important for many fields. Within the framework of the work, various optical recording materials for direct holographic recording were studied. The advantage of grids acquired during the study is that they are made from relatively inexpensive materials, including materials that are easy to synthesize and do not require further purification. Work was done to improve the photosensitivity of the material and to enhance the surface relief after the holographic recording, which reduces the amount of energy required for recording.

Various functional polymers, where light sensitive azo compound is covalently bonded to the polymer matrix, various low molecular weight organic glasses, as well as azo-compound-polymer matrix compound or host-guest system, were studied. Effect of different recording parameters on surface relief grid formation, its mechanism explained. An indirect method for determining the direction of mass movement in a surface relief grid, which does not require any additional equipment or installations, was presented. The work details the effective deletion of surface relief grids, which opens up a reversible grid recording. The promotion work describes the surface relief formation mechanism.

Thesis to be defended:

  1. Main condition for surface relief grid formation is presence of photo-induced  birefringence in the material
  2. Direction of mass movement can be determined indirectly by using diffraction efficiency curves
  3. In compounds where the photosensitive component is chemically bound to the matrix, the highest sensitivity is obtained.