Short-Wavelength Infrared Photon Detector Based on Charge Injection

Short-wave infrared (SWIR) is an interesting region of the electromagnetic spectrum, as it is
highly suitable for imaging through biological tissue and the atmosphere, and yet immune
from the background thermal photon noise. These properties have led to a rapidly growing
interest in the SWIR imaging for exciting new scientific, medical, defense, and consumer
applications.

As such, many efforts in infrared detector research are directed towards improving the
performance of the photon detectors operating in this wavelength range.
In this seminar, I will present a detector with a high internal amplification in addition to a
low noise level. I will introduce principle of operation, challenges, present status and possible
future developments of the detectors. The detectors operate in linear-mode and require only
bias voltage of a few volts. They offer an overall system-level sensitivity enhancement
compared to p-i-n diodes due to their stable internal avalanche-free gain. They have
demonstrated to be one of the most promising paths to high pixel density focal plane arrays
for low flux applications. This detector has recently been used in a commercial medical optical
tomography system, and achieved ~1000 times higher sensitivity at very low light conditions.
Our experimental results suggest that the detectors could be an enabling technology for
portable optical coherence tomography (OCT) systems, allowing use of a micron-scale
tunable laser source (e.g. VCSEL) and a micron-scale detector.