A high throughput static channeled interference imaging spectropolarimeter (CIISP) over 480–960nm spectral range is presented. The CIISP system includes two birefringent retarders and a Savart interferometer employing tempo-spatially mixed modulated mode with no internal moving parts, and offers a robust system and a high optical throughput to resist the instrument noise. The optical layout and operation of the CIISP sensor are presented in addition to the radiometric, spectral and improved polarimetric calibration techniques used with the system. The performance of the system is verified through laboratory tests, and the outdoor measurement demonstrates the sensor’s ability for target identification, color measurement, and agriculture monitoring applications.

A polarization-difference channeled imaging spectropolarimeter (PDCISP) using double-Wollaston prism is presented. It enables simultaneous acquisition of a set of three-channel interferograms corresponding to orthogonal polarization modulation. This brings a large range expanding of optical path difference for useful channels, and the major limitation of channeled spectropolarimetry (CSP), namely the channel crosstalk, can be greatly suppressed by using interferogram difference processing. As a result, full resolution intensity spectrum, as well as high-resolution polarimetric signatures, can be obtained with fewer reconstruction errors, compared to conventional CSP-based systems. The PDCISP is insensitive to alignment errors of retarders and maintains the snapshot feature (1D spatial imaging). The effectiveness of the proposed method is demonstrated by the simulation results.

Large-scale optical fiber phased arrays (OFPAs) are capable of realizing high-power lasers and high-speed beam steering, which are widely used in long-distance detection and communication. However, dephasing occurring from optical fiber jitter and power amplifier noise can reduce beam quality and steering precision in applications. We demonstrate a two-dimensional 64-element OFPA system that employs a stochastic parallel gradient descent algorithm to synchronize the phases and thus achieve high-quality multi-beam output. Using multi-beam steering, the total scan time for covering a certain field of view can be shorter compared to single-beam steering. Moreover, an avalanche photodiode array is used to enhance the precision of the voltage for beam steering. Experimental results show that the peak sidelobe ratio of the main beam achieves 23.7 dB, and the speed of the beam steering between two discretionary angles is 128 kHz.

Channeled spectropolarimeters (CSPs) are capable of estimating spectrally resolved Stokes parameters from a single modulated spectrum. However, channel crosstalk and subsequent spectral resolution loss reduce the reconstruction accuracy and limit the systems’ scope of application. In this paper, we propose a spectral–temporal modulation strategy with the aim of extending channel bandwidth and improving reconstruction accuracy by leveraging the hybrid carriers and allocating channels in the two-dimensional Fourier domain that yield optimal performance. The scheme enables spectral bandwidth and temporal bandwidth to be traded off, and provides flexibility in selecting demodulation strategies based on the features of the input. We present an in-depth comparison of different systems’ performances in various input features under the presence of noise. Simulation results show that the hybrid-modulation strategy offers the best comprehensive performance as compared to the conventional CSP and dual-scan techniques.

Channeled spectropolarimetry (CSP) employing low-pass channel extraction filters suffers from cross talk and spectral resolution loss. These are aggravated by empirically defining the shape and scope of the filters for different measured. Here, we propose a convolutional deep-neural-network-based channel filtering framework for spectrally–temporally modulated CSP. The network is trained to adaptively predict spectral magnitude filters (SMFs) that possess wide bandwidths and anti-cross-talk features that adapt to scene data in the two-dimensional Fourier domain. Mixed filters that combine the advantages of low-pass filters and SMFs demonstrate superior performance in reconstruction accuracy.