A new detection technique for photothermal deflection spectroscopy and photoacoustic deflection spectroscopy is presented. The technique uses a pair of matched multiple slits placed in the path of the probe beam and oriented to block the probe light from the detector in the absence of a deflection signal. Significant improvement in the signal-to-noise ratio and in the frequency bandwidth compared with those available with current techniques is demonstrated.
© 2005 Optical Society of America
Anup Sharma, Gabriel Ycas, Zeyad Alahmed, and Rajendra Gupta, "Detection of photothermal deflection signals with conjugate masks," Appl. Opt. 44, 3110-3116 (2005)