  The real-time, in-line analysis of light polarization is critical in optical
communication networks, which suffers from the complex systems with numerous
bulky opto-electro-mechanical elements tandemly arranged along optical path.
Here, we propose a fiber-integrated polarimeter with nano-thickness by
vertically stacking three two-dimensional (2D) materials based photodetection
units. We demonstrate a self-power-calibrated, ultrafast, unambiguous detection
of linear (LP) and circular polarized (CP) light according to the symmetry
broken induced linear photogalvanic effects (LPGE) and circular photogalvanic
effects (CPGE) in black phosphorous (BP) units, which are twistedly stacked to
substitute traditional mechanical rotation of polarizers. As a demonstration,
we achieve Hadamard single-pixel polarimetric imaging by the polarimeter to
recognize the polarization distributions, showing potential in high-speed
polarization-division-multiplexed imaging and real-time polarized endoscopy.
This work provides a new strategy for next-generation ultracompact optical and
optoelectronic systems, and guides a way for developing high-resolution arrayed
devices with multifunctional pixels.

Optics;Applied Physics