Advanced Disk Lasers: A New Horizon in Solid-state and Semiconductor Laser Design

The laser can become a scientific and industrial penknife. From studying the shortest of events, to precision machining for the fastest of aircraft, it already excels. Yet the potential is greater still. Systems exist with the performance to revolutionise biological imaging, to enable highly sensitive detection of pollutants, but they are often locked in the lab by their bulk, inefficiency and fragility. High performance from a high-power laser requires the efficient removal of heat. In contrast to conventional geometries, using a thin disk of laser material enables aggressive cooling and hence the generation of high powers with extraordinary efficiency. Yet these lasers are bulky. They also use a doped crystal as the material in which to generate the laser light: restricting operation to a limited range of colours. If semiconductors are used, the laser material can be grown with a microscopic layer structure - allowing the colour to be specified anywhere from the ultraviolet through the visible to the mid-infrared. However, generating high power in a good laser beam - a 'pencil of light' - is difficult. If a geometry very similar to a thin-disk laser is used, this problem can be neatly circumvented. This project aims to exploit these synergies to the benefit of both doped-crystalline and semiconductor solid-state lasers. New materials have recently become available - most notably cheaper high-quality diamond - that have the potential to keep systems cool and thus enable the generation of higher powers. Simultaneously, these heat transporting materials can contribute to the design of lasers that are more compact and robust. By applying mirror coatings to the material that generates the laser light, a one-piece laser can be built. These are much better adapted to the vibration and shock of mobile operation. Another major objective of this project is to understand thermal management in these systems to enable high-power, yet more robust, lasers. The penknife is adaptable; the penknife is robust; the penknife is compact. The Advanced Disk Laser concept has the potential to be the laser designer's penknife.