储能系统与砷化镓光电导开关高倍增输出特性关联性研究

It is a problem demanding prompt solution in ultra-fast pulse power research field that triggering GaAs PCSSs to produce the high-power and high-repetition-rate ultra-fast electrical pulse on the order of sub-nanosecond and pico-second with a micro-joule and even nano-joule light, and the key to it is to regulate and control the Lock-on status of high-multiplication GaAs PCSSs. This project intends to research the mutual restriction and influence relation between the energy storage elements of high-multiplication GaAs PCSSs and its output characteristics, cause the optically activated charge domain within GaAs PCSSs to switch to quenching mechanism by changing the energy storage system, and experimentally obtain the correlation rules between the different physical parameters of capacitive energy storage and transmission line energy storage and the pulse width, rising edge and peak of high-multiplication GaAs PCSSs output electrical pulse, so as to reveal the regulation and control mechanism of different energy storage modes on the Lock-on time, as well as the physical essence of triggering optical excitation quenching domain, induce the critical conditions for optically activated charge domain to switch to quenching mode, and establish the physical model about the regulable parameters of energy storage system as well as the output electric pulse peak and repetition frequency. Moreover, it will focus on the causes, stability conditions and control methods for rapid quenching of optically activated charge domain in GaAs PCSSs under the nonequilibrium state of high repetition frequency.

用微焦乃至纳焦量级的弱光触发GaAs光电导开关（GaAs PCSSs）产生亚纳秒及皮秒量级的高功率高重复频率超快电脉冲，是超快脉冲功率研究领域亟待解决的问题，而实现调控高倍增GaAs PCSSs的锁定状态（Lock-on）是其关键。本项目拟研究高倍增GaAs PCSSs的储能元件与其输出特性的相互制约与影响关系，通过改变储能系统诱发GaAs PCSSs内部的光激发电荷畴进入猝灭模式机制，从实验上获得电容储能和传输线储能各物理参数对高倍增GaAs PCSSs输出电脉冲的脉宽、上升沿和峰值的相关性规律，揭示不同储能模式对Lock-on锁定时间的调控机理、以及引发光激发猝灭畴的物理本质，归纳出光激发电荷畴进入猝灭模式所需的临界条件，建立储能系统可调控参量与输出电脉冲峰值和重复频率的物理模型。重点解决高重频非平衡态下GaAs PCSSs中光激发电荷畴迅速猝灭的起因、稳定性条件和控制方法。

高功率超快电脉冲（纳秒、亚纳秒、皮秒）在高技术领域如太赫兹技术、条纹相机、武器点火、惯性约束核聚变以及宽带雷达等领域具有重大作用，属于国家重大需求。而产生高功率超快电脉冲的核心技术就是开关技术，与其它开关相比，光电导开关在产生超快电脉冲方面具有无可替代的优势。对于光电导开关的触发光源，激光二极管（Laser diode 简称LD）相比于其它固体激光器，虽然具有体积小、易集成和价格低等优点，但是其输出单脉冲光能仅为微焦乃至纳焦量级。如何利用LD弱光触发光电导开关产生纳秒以及亚纳秒量级的高功率高重复频率的超快电脉冲，这无论是在器件物理机理还是在器件研制方面都面临诸多国际难题，. 本项目研究了高倍增GaAs PCSSs的储能元件与其输出特性的相互制约与影响关系，通过改变储能系统诱发GaAs PCSSs内部的光激发电荷畴进入猝灭模式机制，阐明高重频下储能元件的放电特性对开关内部瞬态电场、载流子雪崩强度、以及载流子输运的调控物理机理，明确高重频下光激发电荷畴进入稳定猝灭模式临界电场条件，揭示储能系统对电荷畴进入猝灭模式的调控机制，利用模特卡罗模拟仿真了GaAs PCSSs超快导通过程，仿真结果表明碰撞电离是载流子倍增的基础，载流子辐射复合再吸收是电荷畴形成和快速传播根本原因，提出了利用内部电场调控方法控制载流子的倍增，进而抑制电荷畴的形成和传播，最后达到控制脉宽的目的。. 通过设计并实现了用脉宽为20~100ns、波长为905nm、能量为微焦量级的LD弱光触发GaAs PCSSs，得到输出电脉冲脉宽在700ps到10ns重复频率在10kHz的超快脉冲源。完成了利用弱光触发GaAs PCSSs产生具有载流子雪崩倍增效应的强电流脉冲，解决了输出比触发光脉冲宽度更窄的亚纳秒高重复频率的前沿科学问题。项目研制的超快高功率开关可应用在超宽带脉冲源的研制方面，并为高重频亚纳秒电脉冲在电子干扰和电子对抗等领域的应用打下一定的基础。同时利用本项目提出的产生高重复频率超快脉冲序列方法，设计出了高性能太赫兹辐射源。