Publications by authors named "Xiansong Ren"

Filterless light-ellipticity-sensitive optoelectronic response generally has low discrimination, thus severely hindering the development of monolithic polarization detectors. Here, we achieve a breakthrough based on a configurable circular-polarization-dependent optoelectronic silent state created by the superposition of two photoresponses with enantiomerically opposite ellipticity dependences. The zero photocurrent and the significantly suppressed noise of the optoelectronic silent state singularly enhance the circular polarization extinction ratio (CPER) and the sensitivity to light ellipticity perturbation.

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Article Synopsis
  • Circular polarization detection is crucial for various applications and there's a growing need for integrated detectors with better sensitivity to light's spin state.
  • Current integrated circular polarization detectors often struggle with low circular polarization extinction ratios (CPERs) and poor light absorption.
  • A new design using multiple quantum wells sandwiched between a dielectric chiral metamaterial and a metal grating achieves a CPER of 100 and an absorption efficiency of 54%, making it much more effective than existing devices.
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Single-wall carbon nanotube (SWCNT) thin films are promising for sensitive uncooled infrared detection based on the photothermoelectric effect. The SWCNT film is usually shaped into a belt and diversely doped to form a p-n junction at the center. Under the illumination of a focused incident light, the temperature gradient from the junction to the contacts leads to photoresponse.

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Since 2D materials are typically much more efficient to absorb in-plane polarized light than out-of-plane polarized light, keeping the light polarization in-plane at the 2D material is revealed to be a crucial factor other than critical coupling in light absorption enhancement in a 2D material integrated with a light coupling structure. When the composite of a metal-insulator-metal structure and a 2D material changes from the magnetic resonator form to the metasurface Salisbury screen one, the field polarization at the 2D material changes from a mainly out-of-plane status to a mainly in-plane status. As a result, for graphene, the absorptance enhancement is increased by 1.

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