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

Petr Vojtíšek; Milan Kvĕtoň; Ivan Richter

doi:10.1117/12.2256488

11 November 2016 Monitoring of overmodulation effect in high efficient generally slanted transmission gratings produced in photopolymers

Petr Vojtíšek, Milan Kvĕtoň, Ivan Richter

Author Affiliations +

Proceedings Volume 10151, Optics and Measurement International Conference 2016; 1015115 (2016) https://doi.org/10.1117/12.2256488
Event: Optics and Measurement 2016 International Conference, 2016, Liberec, Czech Republic

Abstract

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.

Citation Download Citation

Petr Vojtíšek, Milan Kvĕtoň, and Ivan Richter "Monitoring of overmodulation effect in high efficient generally slanted transmission gratings produced in photopolymers", Proc. SPIE 10151, Optics and Measurement International Conference 2016, 1015115 (11 November 2016); https://doi.org/10.1117/12.2256488

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available