Integrated on-chip silicon plasmonic four quadrant detector for near infrared light

The ability to accurately track light beams in a given space is highly desired for myriad applications e.g., laser cutting, welding, interferometry, sensing, optical tweezers, free space optical communications, and more. Typically, achieving this goal in the short wave infrared requires the use of a cumbersome and expensive InGaAs photodetector implemented as a four quadrant (4Q) device. In this paper, we experimentally demonstrate an attractive approach by implementing a cost effective novel silicon based plasmonic 4Q photodetector. Our 4Q photodetector is implemented using a CMOS compatible plasmonic enhanced IPE Schottky photodetector and can operate in the short wave infrared band, where conventional silicon photodetectors cannot detect light. We have demonstrated the operation of the device and were able to accurately track optical beams of various beam waists at telecom wavelengths. The demonstrated device is based on standard materials and fabrication techniques which are common in the CMOS industry. As such, it provides an additional important example for the potential of plasmonics in the realization of chip scale novel devices which can be integrated with multiple other functionalities.