Brillouin amplification of weak stokes signals from water based on a double-stage non-collinear system with mixture medium

A scheme is presented for amplifying weak Stokes signals from water using mixture medium of CS 2/CCl 4 in a double-stage non-collinear Brillouin amplification system. A frequency doubled Nd:YAG laser is used to produce single-mode pulses of 5.5-ns duration. Results show that choosing mixture liquid of CS 2/CCl 4 as amplifier medium has advantages over pure CS 2. Maximum gain can be obtained by changing the mixed ratio of medium to eliminate the difference of the Brillouin frequency shift between the generator and amplifier. Signal gain as high as 10 11 is experimentally achieved with an input signal of 8.6×10 -14J using the mixture of 90% CS 2 and 10% CCl 4 as the amplifier medium. © 2011 IEEE.