Study on the Internal Mechanism of APD Photocurrent Characteristics Caused by the ms Pulsed Infrared Laser Irradiation

In this paper, the sampling current characteristics of the external circuit and the internal mechanism of the current generation in APD irradiated by a millisecond pulse laser were studied. The photocurrent of APD irradiated by a millisecond pulse laser with different energy densities was obtained by the sampling resistance of the external circuit. The photocurrent can be divided into a photocurrent stage, conduction stage and recovery stage in the time domain. This is mainly due to the carrier flow in APD, which leads to the lowering of the barrier between the PN junction. The research results of this paper can be extended to the response of the detector to the high-power infrared pulse laser and provide a certain experimental basis for the design of a millisecond pulse infrared laser detection circuit.

Temperature Rise Characteristics of Silicon Avalanche Photodiodes in Different External Capacitance Circuits Irradiated by Infrared Millisecond Pulse Laser

We experimentally studied the interaction between a millisecond pulse laser and silicon avalanche photodiode (Si-APD) in an external capacitance circuit. The temperature rise law of Si-APD irradiated by a millisecond pulse laser under different external capacitance conditions was obtained. The results show that the surface temperature rise in a Si-APD is strongly dependent on the external capacitance. That is, the smaller the external capacitance, the smaller the surface temperature rise. The effect of the external capacitance on the surface temperature rise in a Si-APD was investigated for the first time in the field of laser damage. The research results have a certain practical significance for the damage and protection of mid-infrared detectors.

Comparison of Nano-second and Millisecond Pulse Generators for Biological applications of Electroporation

A phenomenon that transiently increases the permeability of the cells is known as electroporation. It is the basis for number of the applications in biomedical domains. It is essential to consider requirement of high precision and the overall size of electroporator. The recent decades have seen the development of solid-state power electronic modules. The modules enable generation of high voltage millisecond and nano-second pulses with options to reduce the overall size of the equipment. The selective modules are verified with experimental models and available for commercial usage. While the other modules are still undergoing optimization processes. The generator generates pulses for varying performances. Hence, this paper presents knowledge for different nanosecond and millisecond pulse generating circuits for electroporation purposes. The performance parameters like the width of the pulse, its amplitude are compared for different circuit topologies. The performance analysis of different topologies and their impact on the performance of the electroporation at the cell biology level are considered in this paper.