Method for precise evaluation of refractive index modulation amplitude inside the volume Bragg grating recorded in photo-thermo-refractive glass

Abstract

In this paper, we present a method for achieving precise evaluation of amplitude of refractive index modulation (RIM) inside the volume Bragg grating (VBG) recorded in photo-thermo-refractive (PTR) glasses. The Gaussian divergence characteristics of the incident beam is theoretically considered when calculating the angular selectivity of VBG, and the profiles of experimental angular selectivity curves are utilized to determine the value of RIM with one step. The effectiveness of our proposed method is experimentally verified. This method is applicable even if the full width at half maximum (FWHM) of VBG's angular selectivity curve has the same order of magnitude as or is less than the beam divergence.

Small-Sized Interferometer with Fabry–Perot Resonators for Gravitational Wave Detection

“…In References [ 27 , 28 ], the designed volume Bragg grating was fabricated inside photothermorefractive (PTR) glasses. The refractive index modulation (RIM) values inside the VBG recorded in PTR glasses were and at wavelengths 632.8 nm and 1064 nm, accordingly [ 28 ]. These values of the RIM are sufficient to achieve the required sensitivity of the interferometer for detecting gravitational waves.…”

“…Low-loss high-efficiency volume Bragg gratings (VBG) in glasses can be recorded by holographic methods. In References [27,28], the designed volume Bragg grating was fabricated inside photothermorefractive (PTR) glasses. The refractive index modulation (RIM) values inside the VBG recorded in PTR glasses were ∆n = 4.78 • 10 −4 ∆ε 1.4 • 10 −3 and ∆n = 4.37 • 10 −4 ∆ε 1.3 • 10 −3 at wavelengths 632.8 nm and 1064 nm, accordingly [28].…”

Effects of CeO2 and Sb2O3 on the Nonlinear Photochemical Process in Ultrashort Laser Gaussian—Bessel Beams Irradiated Photo—Thermo—Refractive Glass

“…Photo-thermo-refractive (PTR) glass is a widely used multifunctional transparent material for recording volume holographic gratings [1][2][3] and fabricating a variety of integrated optical elements [4,5]. The excellent manifold properties of PTR glass are chiefly determined by its unique photosensitiveness [6] that is related to the dopants of Ag 2 O, CeO 2 , Sb 2 O 3 , and SnO 2 in trace amounts.…”

Characterization of Volume Gratings Based on Distributed Dielectric Constant Model Using Mueller Matrix Ellipsometry

“…Volume gratings, which are formed by introducing a periodic refractive index modulation within the volume of a bulk material, are of great importance and popularly used in optical physics for data storage [1], optical elements [2], as well as optical communications [3]. Many kinds of materials, such as crystals [4], fused silica [5,6], photo-thermo-refractive (PTR) glass [7][8][9], and polymers [10,11], have been employed as the recording media. In order to achieve larger refractive index modulation as well as higher data storage density in flexible devices with lightweight [12][13][14], polymer nanocomposites, with doped nanoparticles [15][16][17][18][19][20][21][22][23][24], has attracted special attentions.…”

“…However, since the spatial distribution is not the only factor affecting the diffraction efficiency [29], it was not always a good predictor on nanoparticle distribution. Chen et al proposed a method based on angular selectivity curves to measure the refractive index modulation (RIM, i.e., the refractive index difference between bright and dark regions) of a volume grating recorded in photo-thermo-refractive glass and achieved high precision [9]. Butcher et al measured the thickness, RIM and duty ratio of a volume diffraction grating using a commercial Fourier-transform spectrometer (FTS) combined with multi-incident angle measurement [30].…”