Open AccessTransmission volume phase holographic gratings in photo-thermo-refractive glass written with femtosecond laser Bessel beams
Author(s) -
Y J Zhang,
G D Zhang,
C L Chen,
Razvan Stoian,
Guanghua Cheng
Publication year - 2016
Publication title -
optical materials express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 66
ISSN - 2159-3930
DOI - 10.1364/ome.6.003491
Subject(s) - materials science , femtosecond , optics , diffraction efficiency , laser , grating , refractive index , holography , diffraction grating , diffraction , phase (matter) , optoelectronics , photorefractive effect , wavelength , physics , chemistry , organic chemistry
International audienceTransmission volume phase holographic gratings were fabricated in bulk photo-thermo-refractive glass using zero-order femtosecond laser Bessel beams and subsequent thermal treatment. Microstructures composed of nano-sized crystals were observed in the exposed regions. The concentration of nano-crystals depended on the writing power, but the size of the nano-crystals was found to be quasi power-independent. Low writing power led to sparse nano-crystals, while optimized writing power achieved dense nano-crystals distribution and high refractive index change. Effects of the gratings thickness, writing laser power and thermal treatment on the diffraction efficiency were investigated. A maximum diffraction efficiency of 94.73% was achieved (at 532 nm testing wavelength) with 1 mm grating thickness at period of 5 μ