Novel semiconductor laser devices and systems featuring in-plane periodic optical nanostructures for quantum, biomedical, imaging and telecommunicatio

该研究项目的目的是在可见光和近红外波长范围内对多种类型的新型半导体激光器进行设计和表征，并在格拉斯哥大学詹姆斯瓦特纳米制造中心以及合作实体（英国国家物理实验室；英国化合物半导体技术全球有限公司等）的设施内成功实施和评估。所讨论的激光二极管是在AlGaAs和AlInGaAsP材料系统中实现的最先进的光电半导体器件，利用平面内分布的一维和二维周期性光学纳米结构（布拉格光栅，光子晶体）与先进的制造技术（电子束纳米光刻，外延再生）相结合，以达到必要的性能水平或/并为激光发射提供非常规的有用特性。该项目的主要目标之一是在680-710nm波长窗口内实现分布式反馈激光器（dbs），用于目前世界上许多研究机构正在开发的新型锶基光学晶格原子钟。这些波长的DFB激光设备以前从未被证明过，随着锶晶格时钟不断推动时间测量精度的界限，它们的效用变得越来越明显，以至于有可能重新定义SI秒。用高保真全半导体dfb取代大型、笨重和昂贵的实验室级外腔激光器，将极大地扩大锶晶格时钟的潜在应用范围，包括航空航天、电信、科学和许多其他目前因重量、成本和/或现有系统的实验性质而受到阻碍的领域。在这方面，该项目的重点是实现这些DFB器件制造的每一个步骤，包括外延材料的设计、模拟、优化和生长，分布式布拉格结构的设计和纳米光刻定义，以及通过大学拥有的反应器中的金属氧化物气相外延（MOVPE）手段进行外延再生。在与英国国家物理实验室的合作下，最终装置的适用性将在实际的锶时钟设置中进行评估。本研究项目的另一部分研究了光子晶体表面发射激光器（PCSEL）的设计、制造和优化，研究和描述了其独特的光学特性，并提出了该器件在生物医学成像和传感、电信、全光信号处理等领域的潜在应用。到目前为止，世界上只有少数研究小组专注于这些设备的研究。它实现了一种分布式布拉格晶格（光子晶体），以建立二维平面内的光反馈，并通过二阶布拉格散射从激光腔中提取光。这导致了广域单模发射，这是任何其他半导体激光器结构无法实现的独特特性，因此自然具有低光束发散。这些器件中的二维平面内反馈允许它们集成到相干耦合阵列中进行功率缩放，并为电信应用的光互调和激光雷达、成像和激光扫描的固态光束转向开辟了潜力。

The aim of this research project is to conduct design and characterization of multiple types of novel semiconductor lasers in visible and near-infrared wavelength ranges and achieve their successful implementation and evaluation within facilities of the James Watt Nanofabrication Centre, University of Glasgow, as well as those of collaborating entities (National Physical Laboratory, UK; Compound Semiconductor Technology Global, Ltd., UK; etc.).The laser diodes in question are state-of-the-art optoelectronic semiconductor devices implemented in AlGaAs and AlInGaAsP material systems, making use of one- and two-dimensional periodic optical nanostructures (Bragg gratings, photonic crystals) distributed in-plane in combination with advanced fabrication techniques (electron beam nanolithography, epitaxial regrowth) in order to achieve necessary level of performance or/and provide unconventional useful properties to the laser emission.One of the main goals of the project involves achievement of distributed feedback lasers (DFBs) within 680-710nm wavelength window for application in novel strontium-based optical lattice atomic clocks currently developed in many research institutions around the world. DFB laser devices in these wavelengths have never been demonstrated before, and their utility is becoming more and more evident as strontium lattice clocks are continuously pushing boundaries of time-measurement precision, to the extent of making it possible to redefine the SI second. Opportunity to replace large, heavy and expensive laboratory-grade external cavity lasers in these setups with high-fidelity all-semiconductor DFBs would dramatically widen the range of potential applications for strontium lattice clocks to include aerospace, telecommunication, scientific, and many other fields currently deterred by weight, cost and/or experimental nature of the existing systems.In this regard, the project is focused on implementation of every single step in fabrication of these DFB devices, including design, simulation, optimisation and growth of epitaxial material, design and nanolithographic definition of distributed Bragg structures as well as epitaxial regrowth by the means of metal-oxide vapour-phase epitaxy (MOVPE) in the University-owned reactor. In collaboration with the National Physical Laboratory, UK, fitness-for-purpose of the resulting devices will be evaluated inside an actual strontium clock setup.Another part of this research project considers design, fabrication and optimisation of the photonic-crystal surface-emitting laser (PCSEL), investigation and description of its unique optical properties and proposal of potential applications for such devices in fields including biomedical imaging and sensing, telecommunications, all-optical signal processing, etc.PCSEL is a relatively new type of semiconductor laser structure, so far with only a few research groups around the world focusing their research on these devices. It implements a distributed Bragg lattice (photonic crystal) in order to establish in-plane optical feedback in two dimensions as well as extract light from the laser cavity via second-order Bragg scattering. This results in broad area single-mode emission, a unique property not achieved by any other semiconductor laser structure, and hence naturally low beam divergence. 2D in-plane feedback in these devices allows for their integration into coherently coupled arrays for power scaling and opens potential for optical intermodulation for telecommunication applications and solid-state beam steering for LIDAR, imaging and laser scanning.