E. F. Pen

Method of characterization of effective shrinkage in reflection holograms

A method is described to evaluate plane-wave volume hologram fringe inclination and spacing, as well as the recording material average refraction index. This evaluation allows us to estimate changes in the hologram parameters due to recording material shrinkage. The method is based on measurements of the incident and diffracted beam Bragg angles for two different wavelengths. The conditions for minimizing measurement errors are obtained. The experimental data are in good agreement with the calculated data.

Method for determining the shrinkage parameters of holographic photopolymer materials

A method has been developed to determine the shrinkage parameters of holographic photopolymer materials (including changes in the mean refractive index and thickness of the recording layer) during hologram recording with a measurement error acceptable for practical applications of these materials. Experimental verification of the method has proved its efficiency.

Optimal optical density of the absorbing holographic materials

The theoretical and experimental estimations of optimal optical density of absorbing holographic photopolymer materials for different schemes of holograms recording are carried out. The estimations are based on analytical equations for dependence of the rate photoinduced change of refractive index and effective thickness of the volume holograms on the initial optical density of the photopolymer. Good accordance of theoretical curves and experimental data is observed. The optimal optical density for material with direct chromophore phototransformation is discussed.

Photopolymer material for recording reflection holograms by He-Ne and Kr+ lasers

The results of the research of photopolymer material sensitive to the red area of spectrum (both He-Ne (632 nm) and KR + (647 nm) lasers can be used) for recording of the volume phase reflection holograms are presented. The basic composition and method of the fabrication of holographic photopolymer films (HPPF) on the Mylar substrate are described. The optical properties and holographic characteristics of obtained material were measured by two methods: real-time kinetics of the diffraction efficiency (DE) growth and spectral response of reflection mirror holographic grating.

Method for research of dynamics of the spectral characteristics of reflection holograms in photopolymer materials

A new spectrophotometric method to measure the response of spectral characteristics of reflection holograms on photopolymer materials simultaneously with the process of recording the hologram is proposed and realized. The results of experiments, in particular on the influences of shrinkage of thickness of recording media on the shift of the spectral response of the reflection hologram are considered.

Spectral Characteristics of Holographic Photonic Crystal Models

A technique of calculating the spectral characteristics of model holographic photonic crystals (PhCs), including those with spatial structure defects, is presented. This technique is based on the model of a multilayer system of thin dielectric films and the calculated refractive index profile of the PhC structure along selected crystallographic directions. The calculation results of the studied characteristics for various examples of PhC structures are given.

Experimental study and modeling of holographic photonic crystals with defects of the spatial and band-gap structures

Results of experimental studies and modeling of holographic photonic crystals (PCs) with defects of their spatial and band-gap structures and also of studying quasi-crystals are presented. Thicklayer photopolymer materials with a hybrid matrix formed on the basis of the sol-gel technology are used for PC production. A method of obtaining delocalized defects is proposed and implemented. A code is written for computer modeling of the spatial PC structure, which offers a clear idea about the appearance of the synthesized crystal and the expected spectral characteristics.

Simulation of the Spatial Pattern and Band-Gap Structure of Holographic Photonic Crystals

Simulation software of the spatial pattern and band-gap structure of the holographic photonic crystals is developed for the research—education purposes. Friendly GUI and training technique elaborated. Examples of the 1D–3D model structures of photonic crystals and their transmission spectrums are given.

How the inhomogeneity of volume holograms in photopolymer materials affects their selective properties

This paper presents an experimental study and modeling of the selective properties of transmissive and reflective volume holograms in photopolymer materials. The treatment takes into account how the selectivity response is affected by the inhomogeneous absorption of light, the thickness shrinkage of the recording layer, the variation of the mean value and modulation of the refractive index over the depth of the hologram, and the curvature of the interference fringes.

Holographic recording of superimposed gratings by angle multiplexing in photopolymers with light-induced changing of optical absorption

The results of theoretical investigation of recording superimposed holographic gratings of transmitted type in optical absorbent photopolymeric materials are presented in the report. We consider the case of serial record of superimposed holographic gratings with angle multiplexing. The influence of photopolymer material parameters on diffraction effectiveness of superimposed holographic gratings is investigated in the work. It shows that the change of optical absorbent photopolymeric material during record may strongly change integrated diffraction characteristics or the recorded holographic gratings.