Spectral interference contrast based non-contact photoacoustic microscopy realized by SDOCT

We introduce a method to extract photoacoustic (PA) signal from contrast reduction of interference spectrum acquired by spectral domain optical coherence tomography (SDOCT). This all-optical detection achieved in a noncontact manner directly on the water surface covered on the sample by using its specular reflection. During SDOCT exposure, the phase of interference spectrum keeps shaking according to the water surface vibration induced by PA excitation. This results in interference contrast reduction which is quantified by FFT for PA imaging. Tungsten filament, asparagus fern leaf and mouse auricle were imaged to demonstrate the method.