InSb pixel loaded microwave resonator for high-speed mid-wave infrared detection

High-speed mid-wave infrared (MWIR) detectors are of significant interest for a wide range of applications in communication and spectroscopy. High-speed photodetection is conventionally achieved using reverse biased semiconductor p-i-n junction devices. However, implementing such structures in the mid-infrared (mid-IR) is challenging due to both the limited available material platforms and challenges associated with device design. Here we demonstrate a high-speed MWIR detector architecture that uses a microwave resonator circuit loaded with a photoconductive indium antimonide (InSb) pixel, originally grown highly lattice-mismatched on a GaAs substrate. Time domain measurements demonstrate sub-nanosecond detector response at temperatures from 77 K to room temperature. Frequency response measurements demonstrate that optical signals modulated at frequencies as high as 2 GHz can be well resolved up to room temperature. Time domain circuit simulations support the experimentally measured short minority carrier lifetimes in the InSb pixel, while also suggesting a circuit time constant of ~200 ps, which is ultimately the limiting factor for the bandwidth of the presented detector architecture. Our results provide an alternative approach for the development of contact-free, high-speed infrared detectors capable of directly interfacing with microwave components and structures for a range of RF/mid-IR applications.

高速中波红外（MWIR）探测器在通信和光谱学的广泛应用中具有重大意义。高速光电探测通常使用反向偏置的半导体p - i - n结器件来实现。然而，由于可用材料平台有限以及与器件设计相关的挑战，在中红外（mid - IR）实现此类结构具有挑战性。在此，我们展示了一种高速MWIR探测器架构，它使用一个加载有光电导锑化铟（InSb）像素的微波谐振器电路，该像素最初是在砷化镓衬底上高度晶格失配生长的。时域测量表明，在77 K到室温的温度范围内，探测器响应时间在亚纳秒级别。频率响应测量表明，在高达2 GHz的调制频率下的光信号在室温下都能很好地被分辨。时域电路模拟支持了实验测得的InSb像素中少数载流子的短寿命，同时也表明电路时间常数约为200 ps，这最终是所提出的探测器架构带宽的限制因素。我们的研究结果为开发无接触、高速红外探测器提供了一种替代方法，这种探测器能够直接与微波元件和结构连接，适用于一系列射频/中红外应用。