Adaptive compensation of thermally induced phase aberrations in Faraday isolators by means of a DKDP crystal

Abstract In this paper, we describe adaptive compensation of thermal lens in a Faraday isolator using a DKDP crystal. Thermal lens measurements were made with a modification of the conventional Hartmann sensor -a 2D scanning Hartmann sensor. Our experiments showed that a DKDP crystal does not influence the isolation ratio of Faraday isolator and efficiently compensates for thermal lens. The negative effect produced by the thermal lens is estimated as the amount of power losses from the original beam mode (Gaussian mode in our experiments). Without compensation the losses were measured to be about 25% for 45 W radiation power and were compensated to less than 0.5% by a negative thermal lens in a 5.5 mm-thick DKDP crystal. Numerical extrapolation of experimental data to a higher power range has shown that for the powers up to 150 W, power losses can be made less than 5%

A review on magneto-optical ceramics for Faraday isolators

As a promising magneto-optical (MO) material applied in Faraday isolators, magneto-optical ceramics possess excellent comprehensive properties and have attracted much attention these years. Herein, we review the fabrication and properties of magneto-optical ceramics including garnet, sesquioxide, and A2B2O7 ceramics. Some of the ceramics have been proved to possess applicable performance, while further studies are still needed for most of the magneto-optical ceramics. Aiming at the application for isolators, the research status, existing problems, and development trends of magneto-optical ceramics are shown and discussed in this review

High-vacuum-compatible high-power Faraday isolators for gravitational-wave interferometers

Faraday isolators play a key role in the operation of large-scale gravitational-wave detectors. Second-generation gravitational-wave interferometers such as the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo will use high-average-power cw lasers (up to 200 W) requiring specially designed Faraday isolators that are immune to the effects resulting from the laser beam absorption–degraded isolation ratio, thermal lensing, and thermally induced beam steering. In this paper, we present a comprehensive study of Faraday isolators designed specifically for high-performance operation in high-power gravitational-wave interferometers

Thermal effects in the Input Optics of the Enhanced Laser Interferometer Gravitational-Wave Observatory interferometers

We present the design and performance of the LIGO Input Optics subsystem as implemented for the sixth science run of the LIGO interferometers. The Initial LIGO Input Optics experienced thermal side effects when operating with 7 W input power. We designed, built, and implemented improved versions of the Input Optics for Enhanced LIGO, an incremental upgrade to the Initial LIGO interferometers, designed to run with 30 W input power. At four times the power of Initial LIGO, the Enhanced LIGO Input Optics demonstrated improved performance including better optical isolation, less thermal drift, minimal thermal lensing, and higher optical efficiency. The success of the Input Optics design fosters confidence for its ability to perform well in Advanced LIGO

Media 3: Drastic reduction of thermally induced depolarization in CaF₂ crystals with [111] orientation

Originally published in Optics Express on 04 June 2012 (oe-20-12-13357

Media 4: Drastic reduction of thermally induced depolarization in CaF₂ crystals with [111] orientation

Originally published in Optics Express on 04 June 2012 (oe-20-12-13357

Media 2: Drastic reduction of thermally induced depolarization in CaF₂ crystals with [111] orientation

Originally published in Optics Express on 04 June 2012 (oe-20-12-13357