David Tanner / Last modified: 5 August 16.
The LIGO experiment, one of the largest projects ever undertaken
by the US National Science Foundation, recently detected gravitational waves from the
inspiral of two 30 stellar mass black holes. These waves were predicted 100 years ago by
Einstein's general theory of relativity but had never before been observed directly.
The LIGO observatory consists of three separate laser interferometers,
one in Washington State, one in Louisiana, and a third (planned) in India.
These are Michelson interferometers,
with Fabry-Perot cavities in the arms to increase the storage time of light
in the interferometer. The arms are 4 km in length,
allowing precise measurement of the motion of test masses which make up
the end mirrors of the interferometers.
LIGO group is carrying out analysis of the
data from the interferometers, studying advanced
configurations for the LIGO detector, and built the input
optics for both initial and advanced LIGO.
Sikivie and Neil Sullivan,
I'm involved in a full-scale dark-matter axion
search at the University of Washington called the Axion Dark Matter eXperiment (ADMX). ADMX searches for axions in out galactic halo through their conversion to photons in a resonant cavity permeated by a strong magnetic field. The Florida group
contributes to the high-resolution spectral analysis package of this experiment,
oversaw the acquisition of a dilution refrigerator for the Gen 2 ADMX upgrade, and is working on cavity design for higher-frequency searches.
Another axion search, carried out in collaboration with Guido Mueller , is the
ALPS (Any Light Particle) experiment at DESY. This is a "light-shining-through-walls" experiment in which axions are produced in one resonant cavity carrying high circulating power laser light and inside a strong dipole magnet, flow through a wall (where photons are blocked) and reconvert into photons in a second cavity/magnet arrangement.