Photonic Spin-Hall Differential Microscopy

The visualization of transparent phase objects such as living cells and tissues plays an important role in biological research. Transparency and invisibility caused by weak scattering and absorption make it challenging to image phase objects. Here, we propose differential microscopy based on the photonic spin Hall effect at a simple glass interface. We find that the photonic spin Hall effect can perform a spatial differentiation operation on the phase distribution, and therefore is extremely sensitive to the structures of phase objects. By incorporating this into a bright-field microscope, high-contrast images of pure phase objects can be achieved. We further reconstruct the phase distribution by biased imaging, which provides potential possibilities for high-resolution reconstruction and quantitative analysis of phase images. Compared with the conventional differential-interference-contrast microscope, which requires the introduction of complicated phase-contrast devices into a bright-field microscope, our proposed photonic spin-Hall differential microscopy requires only a simple glass interface. The combination of the photonic spin Hall effect and a bright-field microscope enables compact and low-cost differential microscopy, which may lead to important applications in versatile and high-contrast biological imaging.