EAGER: Generation of Laguerre Gaussian Beams in a VECSEL cavity

激光现在在现代世界中无处不在。在过去的二十年中，由于能够为定制的应用雕刻激光束轮廓，出现了无数的新应用。 被称为拉盖尔-高斯（LG）光束的环形光束有望大大增强经典和量子领域的通信信道。 LG光束的各种应用需要大范围的工作波长和功率，目前还没有统一的光源。拟议的工作旨在探索创建高功率，可调谐和紧凑的LG光束源所需的基础光学科学。 该方法是建立在现有的垂直外腔面发射激光器（VECSELs）的技术，已被证明是高功率和可调谐高斯光束的来源。 我们提出的方法是将模式控制元件引入激光腔中，以这种方式强制产生LG而不是高斯光束。 我们的最终目标是能够以一种保留现有VECSEL技术的高功率、可调性和紧凑性的方式实现这一目标。 拉盖尔-高斯（LG）光束由于其在大范围的应用和基础科学中的巨大用途而具有巨大的需求。 相应的光束携带光学角动量（OAM），其特征在于在横向平面中的螺旋相位变化。 尽管有众多的应用，高功率和可调LG模式的紧凑型源的发展仍然是一个重大的挑战。 本EAGER建议的目标是开发一个统一的和紧凑的源LG模式，可以提供高功率和波长可调谐性的双重优点。 特别是，我们将探讨的机会和限制，扩展目前的VECSEL技术，以产生LG光束的方式腔内模式转换，如果成功打开大门，可调谐LG光束的高功率源。 因此，拟议的研究对应用科学和基础科学都有影响，从未来的通信和信息处理技术到量子信息和纳米技术的基础研究。该研究将结合先进的半导体激光器腔，模式混合，非线性光束的产生，和基于应用的表征联合收割机的建模和实验研究。

Lasers are now ubiquitous in the modern world. In the past two decades, a myriad of new applications have arisen due to the ability to sculpt the laser beam profile for tailor made applications. Annular shaped beams called Laguerre-Gaussian (LG) beams promise to greatly enhance communications channels, both in the classical and quantum domains. The variety of applications of LG beams calls for a large range of operating wavelengths and powers, and at present there is no unified source. The proposed work is aimed at exploring the basic optical science needed to create a high-power, tunable, and compact source of LG beams. The approach is built upon the existing technology of Vertical External Cavity Surface Emitting Lasers (VECSELs) that have been demonstrated as a source of high-power and tunable Gaussian beams. Our proposed approach is to introduce mode control elements into the laser cavity in such a way to force the generation of LG as opposed to Gaussian beams. Our ultimate goal is to be able to do this in a way that preserves the high-power, tunability, and compactness of the existing VECSEL technology. Laguerre-Gaussian (LG) beams are in great demand due to their tremendous utility over a large range of applied and fundamental sciences. The corresponding light beams carry optical angular momentum (OAM) and are characterized by a spiral phase variation in the transverse plane. Despite numerous applications the development of a compact source of high power and tunable LG modes remains a major challenge. The goal of the present EAGER proposal is to develop a unified and compact source for LG modes that can deliver the dual virtues of high power and wavelength tunability. In particular we shall explore the opportunities and limitations of extending current VECSEL technology to produce LG beams by means of intracavity mode conversion, which if successful opens the door to a high-power source of tunable LG beams. The proposed research therefore has implications for both applied and basic science, from future communications and information processing technologies, to fundamental research in quantum information and nanotechnology. The research will combine modeling and experimental investigation of advanced semiconductor laser cavity, mode mixing, nonlinear beam generation, and application based characterization.