A differential photoacoustic imaging system
نویسندگان
چکیده
We describe a differential photoacoustic (PA) imaging system in which almost equal intensity beams modulated 180' out of phase illuminate two regions of a sample in a PA cell. For two regions that are both optically and thermally similar and also homogeneous, the resulting signal is almost zero but if one region has a sub-surface defect this will give an increased signal. This differential signal has a much higher signal to noise ratio than conventional PA systems.
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