Novel Tunable Light Source Based On A Laser Ionized Capacitor Array -- An Electromagnetic Accordion

项目编号：ECS-9632735项目负责人：Thomas Katsouleas题目：基于激光电离电容器阵列的新型可调谐光源——一种电磁手风琴。将研究一种新型辐射源的基本原理，该辐射源具有高功率、可变脉冲长度和超过数量级的宽可调性。这种方法可以被描述为一种“电磁手风琴”，在这种手风琴中，一个短激光脉冲被用来电离一组交替充电的电容器板之间的低压工作气体。激光产生的移动电离锋产生时变介电函数，将电容器的静电场转化为电磁辐射。本质上，激光扫过静态波形，像手风琴一样把它压缩成一个相似但传播时间缩短的电磁波串。通过改变气体压力和/或电容器极板间距来控制输出辐射的频率；原则上，频率输出可以在30年内变化。此外，由于输入波形可以通过改变电容板的偏置和尺寸而任意成形，因此可以将输出辐射设计为具有任意频率啁啾、幅度调制或周期数。这项研究将导致一种单一紧凑设备的发展，该设备将产生毫瓦脉冲的相干辐射，跨越从微波到可见光的光谱，具有任意形状和啁啾或编码的波形。这种装置可以经济地为研究、工业和医学提供许多光源需求。

Proposal Number: ECS-9632735 Principal Investigator: Thomas Katsouleas Title: Novel Tunable Light Source Based on a Laser Ionized Capacitor Array- An Electromagnetic Accordion The fundamental principles of a new radiation source capable of high power, variable pulse length and broad tunability over orders of magnitude will be investigated. The approach may be characterized as an "electromagnetic accordion", in which a short laser pulse is used to ionize a low pressure working gas between an array of alternately charged capacitor plates. The moving ionization front produced by the laser creates a time varying dielectric function that converts the static electric field of the capacitors into electromagnetic radiation. In essence, the laser sweeps up the static waveform and squeezes it like an accordion into a similar but shortened propagating electromagnetic wavetrain. The frequency of the output radiation is controlled by changing the gas pressures and/or the capacitor plate spacing; in principle, the frequency output could be varied over three decades. Moreover, since the input waveform can be arbitrarily shaped by varying the bias and size of the capacitor plates, the output radiation can be designed to have arbitrary frequency chirp, amplitude modulation, or number of cycles. The research will lead to the development of a single compact device that would produce MW pulses of coherent radiation spanning the spectrum from microwaves to visible light, with arbitrarily shaped and chirped or encoded wavetrains. Such a device could economically provide many of the light source requirements for research, industry and medicine.