Fast quasi-optical phase shifter based on induced photoconductivity in silicon

A 30 GHz commutator aimed to switch phase of 0.1-1 mks, 1-100 MW microwaves in pulse compression systems like SLED is suggested. The commutator in a form of circular (100 mm) Si-disk put on a surface of copper mirror is based on creation of thin photoconductive layer in high purity low-loss silicon. The photoconductivity is caused by means of Ti:Sa laser radiation (1-10 mJ, 0.1 ps) with wavelength 795 nm. Results of low power tests carried out with the 180 degrees phase shifter, which was operated with Gaussian wavebeam, have showed high efficient phase switching for time ~1 ns. High-power tests are scheduled in CERN on the end of 2007.