NEW CONCEPT FOR CONTROLLING MODES IN A FABRY-PEROT

法布里-珀罗由两个平行的反射镜组成，用于定义激光器、可调谐滤光器、频谱分析仪和一些调制器中的模式。反射镜通常是介电四分之一波叠层，在整个厚度范围内以分布的方式反射。这个项目的目的是证明，根据折射率的仔细控制，四分之一波叠加镜(也称为分布式布拉格反射镜)的有效穿透长度可以变得很大，可以是负的、零的，或者是大的和正的。这一概念将被应用于：a)生产单模半导体激光器和b)研究高速空间光调制器。智力优势：该项目源于对这些分布反射镜的有效穿透长度的新的解析解，并在解中发现了极点和零点。这些区域的存在已经通过计算机进行了检查，并且意味着在光学设备和系统中有许多重要的应用。定义和演示这些应用程序是一项令人兴奋的挑战。例如，这将是第一次通过控制反射镜中的折射率来实现对法布里-珀罗模间距的控制。此外，负穿透长度意味着超光速反射，这是解释和寻找应用的一个重要的智力挑战。要实现这种高反射率的制度，需要在金属(或金属薄膜)上沉积分布反射器或使用大量的层对。在任何一种情况下，都需要仔细控制薄膜的折射率。这是将在实验室进行的技术挑战。它将得到作者在1983年介绍的薄膜测量技术的帮助，并将使用达特茅斯大学开发的薄膜沉积技术。宽带影响：控制分布式反射镜的有效穿透长度提供了广泛的应用。这些措施包括：廉价的单模半导体激光器，每脉冲功率更大的锁模半导体激光器，更简单的光纤法布里-珀罗可调谐滤光器，实用的可变光衰减器，更好的法布里-珀罗光传感器，更简单的VCSEL制造，以及共振光电探测器。最后，非线性和电驱动的波导调制器和空间光调制器变得实用。这一概念还可用于实现光波导中的平面直角弯曲，这通常需要纳米结构的光子带隙材料。这项研究也将对培养工程人才产生积极的影响，因为P.I.是女性，而提出发起研究的博士生也是女性。达特茅斯大学作为一所大学，从事最先进的研究，为教学研究机构提供了一个典范。

A Fabry-Perot consists of two parallel mirrors used to define modes in lasers, tunable filters, spectrum analyzers, and some modulators. The mirrors are usually dielectric quarter wave stacks that reflect in a distributed way, throughout their thickness. The objective of this project is to demonstrate that the effective penetration length into the quarter wave stack mirror (also called a distributed Bragg reflector) can become large and negative, zero, or large and positive, depending on careful control of the refractive indices. This concept will then be applied to: a) producing single mode semiconductor lasers and b) investigating high speed spatial light modulators.Intellectual merit: this project stems from a new analytic solution to the effective penetration length in these distributed mirrors and the discovery of both a pole and a zero in the solution. The existence of these regimes has been checked by computer and implies a number of important applications in optical devices and systems. Defining and demonstrating these applications is the exciting challenge. For example, this will be the first time that control of a Fabry-Perot mode spacing is achieved by controlling the refractive index in its mirrors. Furthermore, a negative penetration length implies superluminal reflection, which is an important intellectual challenge to explain and find applications for.To achieve this regime with high reflectivity requires the distributed reflector be deposited on metal (or a metal film) or to use a large number of layer-pairs. In either case, careful control of the refractive indices of the films is required. This is the technical challenge that will be undertaken in the laboratory. It will be helped by a thin film measurement technique introduced by author in 1983 and will use a thin film deposition technology that was developed at Dartmouth.Broader impact: Controlling the effective penetration length of a distributed mirror offers a wide range of applications. These include: inexpensive single mode semiconductor lasers, mode-locked semiconductor lasers with more power per pulse, simpler fabrication of fiber Fabry-Perot tunable filters, a practical variable optical attenuator, better Fabry-Perot optical sensors, simpler fabrication of VCSEL's, and resonant photo-detectors. Finally, nonlinear and electrically driven waveguide modulators and spatial light modulators become practical. The concept pioneered here can also be used to achieve in-plane right angle bends in waveguides, which usually requires nanostructure photonic bandgap materials.This research will also have a positive impact on training engineering personnel, since the P. I. is a woman and the Ph. D. graduate student proposed to initiate the research is also a woman. Dartmouth as a college is involved in state-of-the-art research and provides a model for teaching-research institutions.