Non-Geiger mode single photon detector with multiple amplification and gain control mechanisms.

摘要

In this thesis, we present a new device principle, Multiple Amplification Gain with Internal Control (MAGIC), as a new class of detectors that promise high single-photon detection efficiency and a much wider dynamic range than any single photon detectors reported to date. A preliminary version of such device that contains some key features of the MAGIC detector with multiple gain mechanisms and gain control characteristics has been implemented experimentally which has shown a sensitivity of 10 photons per bit and a much wider dynamic range than Geiger-mode SPADs (Single Photon Avalanche Detectors). The device has three gain mechanisms monolithically integrated into it along with a negative feedback mechanism. The integrated gain provides a strong output signal while being operated below breakdown voltage and the negative feedback mechanism controls the gain fluctuation. Therefore the signal to noise ratio is improved which is important for high sensitivity. This new device concept holds promise for single photon sensitivity, high detection efficiency, and wide dynamic range; and the device can achieve the above desirable characteristics at bias below the breakdown voltage to assure high device reliability. A Unified Device Model, based on physical model of the invented device has been developed to analyze its fundamental characteristics and also compare the results with conventional SPADs with different quenching mechanisms. The model takes into account all three stochastic processes that control the overall gain and fluctuations of photocurrent of the proposed device, and the model for different types of SPADs may be considered as a special case of the comprehensive model. By comparing the proposed device with passively quenched and self-quenched SPADs, the invented device shows a significant increase in detection efficiency, orders of magnitude lower error rates for single photon detection, and much greater dynamic range, attributed to the integration of avalanche multiplication and bipolar amplification as two coupled gain mechanisms in conjunction with the self-quenching feedback to regulate the output signal.