The status and prospects of the Q & A experiment with some applications
arXiv:0911.4776 · doi:10.3204/DESY-PROC-2009-05/mei_hsien-hao
Abstract
Motivated to measure the QED birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first review our 3.5 m Fabry-Perot interferometer together with our results of measuring Cotton-Mouton effects of gases. We are uprading our interferometer to 7 m armlength with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We will use 532 nm Nd:YAG laser as light source with cavity finesse around 100,000, and aim at 10 nrad/Hz^{1/2} optical sensitivity. With all these achieved and the upgrading of vacuum, QED birefringence would be measured to 28% in about 50 days. Along the way, we should be able to improve on the dichroism detection significantly.
4 pages, 1 table and 2 figures, to be published in the 5th Patras Workshop on Axions, WIMPs and WISPs held at the University of Durham on 13-17 July 2009