Monitoring of overmodulation effect in high efficient generally slanted transmission gratings produced in photopolymers

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F16%3A00469352" target="_blank" >RIV/61389021:_____/16:00469352 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1117/12.2256488" target="_blank" >http://dx.doi.org/10.1117/12.2256488</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1117/12.2256488" target="_blank" >10.1117/12.2256488</a>

Result language

angličtina

Original language name

Monitoring of overmodulation effect in high efficient generally slanted transmission gratings produced in photopolymers

Original language description

In our laboratory, we use for fabrication of volume phase diffraction gratings a photopolymer recording material Bayfol HX. It is an extremely effective recording material; a high value of the refractive index modulation is obtained already during a holographic exposure. The value of this refractive index modulation influences the diffraction properties (e.g. efficiency) of the recorded gratings and, in the case of transmission gratings, the growth of this modulation beyond the optimal value leads to an effect of so called overmodulation. This effect is, in the most cases, unwanted as it causes the decrease of the diffraction efficiency from its maximum value (practically close to 100%). The analysis whether the grating is over- or under- modulated is relatively difficult as the value of the refractive index modulation can’t be measured directly and it is evaluated from the measurement of the diffraction efficiency. However, the obtained value can be often incorrect due to the overmodulation effect. In this contribution, we would like to extend (to include any arbitrary slanted transmission gratings) and discuss a simple measurement method for the determination of the correct value of the refractive index modulation based on a multiple/two-wavelength measurement of a diffraction efficiency of transmission gratings. The theoretical idea of this method and also experimental results obtained on photopolymer Bayfol HX will be presented. From practical point of view, this approach help us mainly for correct adjustment of exposure parameters to reach efficient gratings

Czech name

—

Czech description

—

Type

D - Article in proceedings

CEP classification

JI - Composite materials

OECD FORD branch

—

Project

<a href="/en/project/LO1206" target="_blank" >LO1206: Modern optical systems and technologies</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Proceedings of SPIE 10151, Optics and Measurement International Conference 2016

ISBN

978-1-5106-0753-8

ISSN

0277-786X

e-ISSN

—

Number of pages

10

Pages from-to

—

Publisher name

SPIE, Society of Photo-Optical Instrumentation Engineers

Place of publication

Bellingham

Event location

Liberec

Event date

Oct 11, 2016

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

000393154700041