Aperture-Coded Long-Wave Infrared Hyperspectral Imager With Noncryogenic Optomechanical System

The long-wave infrared (LWIR) hyperspectral imagers (HSIs) typically necessitate deep cooling of their opto-mechanical systems to reduce instrument background signal, thereby preventing extremely weak target signal from being drowned out by the background signal. This treatment entails the design and implementation of refrigeration systems and cryogenic optical systems, posing significant demands on the weight and power consumption resources of the working platform. Here, we present the design of a LWIR HSI based on aperture coding which features a spatial resolution of 221×256 pixels and 100 spectral channels in 8-12.5μm band. Compared with the traditional single slit scanning HSI, our HSI acquires approximately 50 times more enhanced target radiation at the focal plane in the case of the same spectral channel number, which enables our HSI to acquire LWIR hyperspectral measurements of a scene without deep cooling of the opto-mechanical system. Lastly, we show the imaging results for both indoor targets and outdoor targets, demonstrating the ability of our HSI to acquire both geometric and spectral information in the scene. We utilize spectral angle mapper (SAM) and noise equivalent temperature difference (NETD) to quantitatively evaluate the performance of our HSI. Our experimental results reveal the average spectral similarity of 94.2% and the NETD of approximately 0.3K@300K in the 8.5-11μm spectral band, with the opto-mechanical system maintained at room temperature.