High-frequency Bragg gratings in a photothermorefractive glass

Abstract

Holographic UV mirrors were recorded in a volume of photothermorefractive glass. This photosensitive silicate glass doped with silver, cerium, and fluorine is transparent in the near-UV, visible, and near-IR spectral regions, and its induced refractive-index change reaches 10(-3). UV radiation of a He-Cd laser at 325 nm was used for Bragg grating recording with a spatial frequency of approximately 9200 mm(-1). The absolute diffraction efficiency of the recorded mirror reached 12.6% at 325 nm and did not deteriorate under the long-time effects of optical irradiation and heating up 400 degrees C.

Performances of volume phase holographic grating for space applications: study of the radiation effect

“…Concurrently to the DCG technology, VPH gratings can be fabricated by inducing a permanent refractive index change in a special PTR multicomponent silicate glass (BragGrate) after exposure to UV radiation followed by thermal treatment [7,8]. This allows fabrication of VPH gratings with absolute diffraction efficiency exceeding 99%, thermal stability at up to 400°C, a laser damage threshold of 40 J∕cm 2 for 8 ns pulses, and a tolerance to CW laser radiation in the NIR region at least up to several tens of kilowatts per square centimeter.…”

“…In that case, high efficiencies of around 100% could be achieved as demonstrated in [7] and [8]. For large bandwidth and high efficiency, DCG gratings are more appropriate.…”

“…The grating is recorded in the bulk of the glass substrate. This technology allows the manufacturing of thicker (several millimeters thick) VPH gratings, which produces a narrower spectrum of the diffracted beam [7,8]. The main selection criteria for these two technologies are performance, in terms of diffraction efficiency, and commercial availability as a bulky component without the need of further processing.…”

Adiabatic three-wave symmetric volume hologram

“…The results of calculations of angular and spectral selectivity of our three-wave symmetric and asymmetric holograms will be also presented in the talk. We believe that the volume phase holograms in photo-thermo-refractive glasses, [5], may greatly benefit from the use of this STIRAP-type configuration.…”

Manufacturing of diffractive elements in fused silica using high repetition rate femtosecond Yb:KGW laser pulses

“…After the exposure, the gelatin is chemically treated and sandwiched between glass plates for better robustness and handling [9]. A new and very promising material for VPG fabrication is Photo-Thermo-Refractive (PTR) glass, which was developed and patented by a CREOL team in the recent decade [10]. It is a silicate based glass with silver, cerium, and fluorine doping.…”