High-performance narrowband thermal emitter based on aperiodic Tamm plasmon structures assisted by inverse design.

Controlling the bandwidth and directionality of thermal emission is important for a broad range of applications, from imaging and sensing to energy harvesting. Here, we propose a new, to the best of our knowledge, type of long-wavelength infrared narrowband thermal emitter that is basically composed of aperiodic Tamm plasmon polariton structures. Compared to the thermal emitter based on periodic structures, more parameters need to be considered. An inverse design algorithm instead of traditional forward methodologies is employed to do the geometric parameter optimization. Both theoretical and experimental results show that the thermal emitter exhibits a narrowband thermal emission peak at the wavelength of 8.6 µm in the normal direction. The angular response of emission properties of the thermal emitter is dependent on the emission angle. We believe that our proposed thermal emitter provides an alternative for low-cost, high-effective narrowband mid-infrared light sources and would have a great potential in many applications.

Narrowband HgCdTe infrared photodetector with integrated plasmonic structure.

The application of plasmonic structure has been demonstrated to improve the performance of infrared photodetectors. However, the successful experimental realization of the incorporation of such optical engineering structure into HgCdTe-based photodetectors has rarely been reported. In this paper, we present a HgCdTe infrared photodetector with integrated plasmonic structure. The experimental results show that the device with plasmonic structure has a distinct narrowband effect with a peak response rate close to 2 A/W, which is nearly 34% higher compared with the reference device. The simulation results are in good agreement with the experiment, and an analysis of the effect of the plasmonic structure is given, demonstrating the crucial role of the plasmonic structure in the enhancement of the device performance.

Long-wavelength infrared selective emitter for thermal infrared camouflage under a hot environment.

Thermal infrared camouflage as a kind of counter-surveillance technique has attracted much attention owing to the rapid development of infrared surveillance technology. Various artificial optical structures have been developed for infrared camouflage applications under cold ambient environment (low thermal radiation), but the realization of infrared camouflage under a hot environment (high thermal radiation) is also highly desirable and has been rarely reported. Here, a lithography-free, ultra-thin, high performance long-wavelength infrared (LWIR) selective emitter for thermal infrared camouflage in a high radiation environment is proposed and experimentally demonstrated. Experimental results show that our designed selective emitter exhibits average emissivity higher than 90% over the LWIR range from 8 to 14 µm and low emissivity less than 35% outside this window. Numerical simulations were performed to optimize the geometrical structures and reveal that such a selective emission effect is attributed to the combination of multiple hybrid plasmonic resonances. LWIR thermal images show that the selective emitter can perfectly blend into the high radiation backgrounds. Furthermore, it is found that the sample displays angle-independent emission properties, indicating that our emitter offers great potential for application in evading large-angle detection.