HETERODYNE-DETECTION OF ULTRASOUND FROM ROUGH SURFACES USING A DOUBLE-PHASE CONJUGATE MIRROR

We present an improved version of the classical heterodyne interferome ter for ultrasound detection, which includes a double phase conjugate mirror (DPCM) in the detection arm. The DPCM performs wave front adapt ation to plane wave of the speckled beam scattered by the rough surfac e of the sample. The performances of the system are analyzed regarding the transmission (approximate to 30%) and fidelity (approximate to 70 %) of the phase conjugation and the response time and etendue of the d evice. An example of application to the detection of laser generated u ltrasound is also presented.