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

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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.