Polarization state tomography technique based on coherent synthesis of polarization state and orthogonal polarization state separation method for comprehensive optical imaging.

Comprehensive optical imaging of the intensity, phase, and birefringent information of the biological sample is important because important physical or pathological changes always accompany the changes in multiple optical parameters. Current studies lack such a metric that can present the comprehensive optical property of the sample in one figure. In this paper, a polarization state synthesis tomography (PoST) method, which is based on the principle of polarization state coherent synthesis and demodulation, is proposed to achieve full-field tomographic imaging of the comprehensive information (i.e., intensity, phase, and birefringence) of the biological sample. In this method, the synthesis of the polarization state is achieved by the time-domain full-field low coherence interferometer, where the polarization states of the sample beam and the reference beam are set to be orthogonal for the synthesis of the polarization state. The synthesis of the polarization state enables two functions of the PoST system: (1) Depth information of the sample can be encoded by the synthesized polarization state because only when the optical path length difference between the two arms is within the coherence length, a new polarization state can be synthesized; (2) Since the scattering coefficient, refractive index and the birefringent property of the sample can modulate the intensity and phase of the sample beam, the synthesized polarization state is sensitive to all these three parameters and can provide the comprehensive optical information of the sample. In this work, the depth-resolved ability and the comprehensive optical imaging metric have been demonstrated by the standard samples and the onion cells, demonstrating the potential application value of this method for further investigation of the important physical or pathological process of the biological tissues.