Low-Noise Dual-Band Polarimetric Image Sensor Based on 1D Bi2 S3 Nanowire.

With the increasing demand for detection accuracy and sensitivity, dual-band polarimetric image sensor has attracted considerable attention due to better object recognition by processing signals from diverse wavebands. However, the widespread use of polarimetric sensors is still limited by high noise, narrow photoresponse range, and low linearly dichroic ratio. Recently, the low-dimensional materials with intrinsic in-plane anisotropy structure exhibit the great potential to realize direct polarized photodetection. Here, strong anisotropy of 1D layered bismuth sulfide (Bi2 S3 ) is demonstrated experimentally and theoretically. The Bi2 S3 photodetector exhibits excellent device performance, which enables high photoresponsivity (32 A W-1 ), Ion /Ioff ratio (1.08 × 104 ), robust linearly dichroic ratio (1.9), and Hooge parameter (2.0 × 10-5 at 1 Hz) which refer to lower noise than most reported low-dimensional materials-based devices. Impressively, such Bi2 S3 nanowire exhibits a good broadband photoresponse, ranging from ultraviolet (360 nm) to short-wave infrared (1064 nm). Direct polarimetric imaging is implemented at the wavelengths of 532 and 808 nm. With these remarkable features, the 1D Bi2 S3 nanowires show great potential for direct dual-band polarimetric image sensors without using any external optical polarizer.

Birefringence and Dichroism in Quasi-1D Transition Metal Trichalcogenides: Direct Experimental Investigation.

Birefringence and dichroism are very important properties in optical anisotropy. Understanding the intrinsic birefringence and dichroism of a material can provide great help to utilize its optical anisotropy. But the direct experimental investigation of birefringence in nanoscale materials is rarely reported. As typical anisotropic transition metals trichalcogenides (TMTCs) materials with quasi-1D structure, TiS3 and ZrS3 have attracted extensive attention due to their special crystal structure and optical anisotropy characteristics. Here, the optical anisotropy properties such as birefringence and dichroism of two kinds of quasi-1D TMTCs, TiS3 and ZrS3 , are theoretically and experimentally studied. In experimental results, the anisotropic refraction and anisotropic reflection of TiS3 and ZrS3 are studied by polarization-resolved optical microscopy and azimuth-dependent reflectance difference microscopy, respectively. In addition, the birefringence and dichroism of ZrS3 nanoribbon in experiment are directly measured by spectrometric ellipsometry measurements, and a reasonable result is obtained. This work provides the basic optical anisotropy information of TiS3 and ZrS3 . It lays a foundation for the further study of the optical anisotropy of these two materials and provides a feasible method for the study of birefringence and dichroism of other nanomaterials in the future.