Research past, present and planned
The goals of the LIGO Lasers and Optics Working Group are described in the LSC White Paper and include work on high-power diode-laser-pumped solid-state lasers, phase modulators, optical isolators and conditioning optics, adaptive core optics control, thermal modeling of interferometers, optics contamination, and core optics figuring and microroughness, diffractive optics and photodiode development.
Research is underway on diode laser pumped solid state lasers including injection locked lasers with both stable (GEO) and unstable cavities (ACIGA), rod based master oscillator power amplifiers (MOPA) (LIGO) and slab MOPAs (Stanford).
Nob Uehara and Benno Willke while at Stanford developed a pre-mode cleaner for the LIGO 10 watt laser in a collaboration with LIGO and Willke working with Rick Savage, Peter King and Stefan Sael installed it in the prototype LIGO Pre Stabilized Laser.
David Reitze, David Tanner, Sunny Yoshido all of the University of Florida and Justin Mansell (http://www.stanford.edu/~jmansell/research.html) of Stanford have developed testing procedure to evaluate the thermal distortions in phase modulators and optical isolators. In addition, the Florida group is developing further the testing procedures for the power handling of phase modulators and isolators.
Several groups including LIGO, ACIGA and Stanford are involved in measuring the optical absorption in crystaline materials which have the potential of being used as advanced core optics.
Interferometers can be operated at higher power if the core optics can be compensated for the distortions induced by beam heating using a second heating element and a wavefront distortion sensor. Mike Zucker and Ryan Lawrence at LIGO-MIT have a program of research into active thermal compensation of core optics.
Ray Beausoleil (firstname.lastname@example.org) of Hewlett Packard is developing a collection of Matlab programs that can be used to perform a static thermal analysis of gravitational wave interferometers. This software is available upon request.
Jordan Camp and daqun Li at LIGO-Caltech are making optics contamination measurements to determine what materials can be used in the LIGO vacuum system.
Optical absorption, surface figure and micro roughness measurements are underway at LIGO-Caltech as part of a development program for new core optics and will be expanded to include promissing new materials.
Non-transmissive diffractive optics are under investigation as a way to avoid the distortions resulting from substrate heating at ACIGA and Stanford.
Photodetectors are being developed and tested in a LIGO-MIT Stanford collaboration.
The LIGO 10 watt Lightwave (Lightwave Electronics http://www.lwecorp.com/) laser has been integrated into a pre-stabilized laser at Caltech by Rick savage, Peter King and Rich Abbott and is being installed at the LIGO Hanford (http://www.ligo.caltech.edu/LIGO_web/hanford/main.html) site.
Bill Tulloch and Todd Rutherford from Stanford Stanford are continuing a study of free space optical amplifier noise which was begun collaboratively with researchers GEO-Glasgow University.
Last Update: 2/19/98