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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F16%3A00309207" target="_blank" >RIV/68407700:21340/16:00309207 - isvavai.cz</a>

Výsledek na webu

<a href="http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2585106" target="_blank" >http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2585106</a>

DOI - Digital Object Identifier

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

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

D - Stať ve sborníku

CEP obor

JA - Elektronika a optoelektronika, elektrotechnika

OECD FORD obor

—

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název statě ve sborníku

SPIE Proceedings - Optics and Measurement International Conference 2016

ISBN

978-1-5106-0754-5

ISSN

0277-786X

e-ISSN

—

Počet stran výsledku

10

Strana od-do

1-10

Název nakladatele

SPIE

Místo vydání

Bellingham (stát Washington)

Místo konání akce

Liberec

Datum konání akce

11. 10. 2016

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000393154700041