Characterization of Polarization Holographic Gratings Obtained on Azopolymer Thin Films by Digital Holographic Microscopy

Veronica Cazac,Vladimir Abashkin,Constantin Loshmanschii,Alexei Meshalkin,Elena Achimova,Vladimir Podlipnov

doi:10.18287/jbpe21.07.030306

Abstract

Polarization diffraction gratings are formed by one-step polarization holographic recording in azopolymer thin films. The evolution of the gratings parameters, such as the modulation of diffraction efficiency and relief depth with regard to different exposure dose is analyzed. Phase-shifting digital holographic microscopy is applied for the measurement of the light-induced polarization diffraction gratings. For the accurate hologram acquisition and reconstruction of the complex amplitude transmitted by the gratings, we performed all-optical (without moving components) phase-shifting implemented within in the imaging system of the digital holographic microscope. The experimental measurement results and theoretical predictions were compared and analyzed.

Highlights

Azobenzene-based photochromic materials have attracted great scientific attention due to the light-induced mass migration, which can be used to create polarization holographic optical elements on thin films as a response to patterned illumination
We introduce phase-shifting Digital holographic microscopy (DHM) for studying polarization holographic gratings (PHG) recorded on azopolymer thin films
Since refractive index modulation is small in azopolymer thin films usually, it suffices to consider only the surface relief modulation produced by modifications in the volume of the azopolymer [15]

Summary

Introduction

Azobenzene-based photochromic materials have attracted great scientific attention due to the light-induced mass migration, which can be used to create polarization holographic optical elements on thin films as a response to patterned illumination. These materials are intriguing because of the reversibility of the photoinduced changes. Digital holographic microscopy (DHM) allows you to visualize amplitude information, color information, and phase information This is especially useful for obtaining information about living cells, tissues, and various biological materials. Various modifications of such microscopes are known, including a digital holographic white light microscope based on spectral phase shifting [7] DHM can be used for 3D analysis of the profile of micro-optical components with the highest resolution [8,9]

Methods

Results

Conclusion