Analysis of structures and technologies of various types of photodetectors used in laser warning systems: a review

Abstract

With the advancement of laser technology in recent decades, this device has been used in a wide range of applications, such as medical sciences, military, industry, holography, spectroscopy, and astronomy. In past years, military operations for better communication depended on radiofrequency. Vulnerability to security threats and exposure to electromagnetic interference were the main problems of this electromagnetic spectrum region. Therefore, attention was drawn to the visible and infrared (IR) regions. This spectrum provided a secure transfer of the data. The probability of intercepting a laser signal is very low due to the divergence of the narrow beam and the coherence of its optical beam. Hence, it has made this device a good candidate for secure military operations. As a result, the laser based-devices and laser-guided weapons (LGW), such as laser target designator and beam riders, have become an undeniable tool on battlefields. Reduction of the vulnerability to the LGW threats by providing laser detection, angle of arrival, wavelength discrimination, and temporal characterization is the main intention of the laser warning system (LWS). This system consists of three major subsystems. The optical subsystem will consist of spectral filters, focusing lenses, and the detection one, which is made of a few detectors in a unique array's configuration [especially IR photodetector (IRPD)], and the processing subsystem. In the last decades, with the progress made in nanofabrication and nanotechnology, consequential research has been done to enhance the performance of IRPDs, such as increasing the production yield, making it simple in the fabrication processes, lowering the fabrication cost, and increasing the operating temperature. This review paper gives a particular concentration to the photodetectors used in the detection subsystem of LWSs. In addition, some nanostructures have been surveyed to enhance the optical coupling and light-matter interaction of IRPD. Also, all studied structures are compared in a table. Finally, the detection subsystem we simulated and built at the Nanoptronics Research Center will be analyzed.

Comparison of Proton and Gamma Irradiation on Single-Photon Avalanche Diodes

“…For infrared wavelengths above 1100 nm, materials with a bandgap of less than 1.1 eV should be used, typically In-GaAs and InP materials [20]. Structural innovations include backilluminated SPADs, vertical double-junction SPADs, substrate-isolated SPADs, 3D-stacked SPADs, non-contact ring guard SPADs and high-detection-efficiency SPADs [21,22]. These novel materials and structures further improve SPADs' detection efficiency and reduce dark counts.…”