LED technology offers significant advantages over halogen and arc lamps in medical imaging due to long lifetimes, ruggedness and potential efficiency. However, LEDs have limitations, limited irradiance and efficiency degradation. Luminescent Concentrators (LCs) present a promising solution as they benefit from LEDs strengths whilst providing high theoretical efficiencies, brightness and generation of new wavelength components. This work introduces a novel approach of achieving a white light source using LED-pumped LCs. By combining various fluorophores, LCs can emit an optimal spectral output for multispectral applications such as endoscopy. The performance of this white light source is evaluated against traditional methods, xenon and halogen lamps, proving its potential as a replacement for aging technologies in medical imaging.
Room-temperature MASERs (Microwave Amplification by Stimulated Emission of Radiation) are coherent sources that exploit stimulated emission to amplify electromagnetic waves at microwave frequencies. Here we report the first demonstration of an LED-pumped maser based on photo-excited triplet states of pentacene in p-terphenyl. The LED light is brightness enhanced and guided using a Cerium-doped Yttrium Aluminium Garnet luminescent crystal that uses light recycling to reach record luminance and power levels. We observe stable maser emission at 1.45 GHz using LED pumping at a much lower pump threshold power. This new maser is cost-effective, safe, and environmentally friendly, and hence ensures a wide variety of potential uses, including more sensitive magnetic resonance body scanners, quantum optical coherence tomography, advanced quantum computer components, portable atomic clocks, and better radio astronomy devices for deep space exploration.
The MASER, analogous to a laser but operating in the microwave range, amplifies electromagnetic waves through stimulated emission. Recent advancements in optically pumping Masers have reinvigorated the field, overcoming limitations such as high vacuum, strong magnetic fields, and extreme temperatures. This work presents a miniaturised hairpin cavity for microwave antenna design utilising optical Maser sources. The miniaturised cavity demonstrates its performance through simulations and experimentally by combining optical pumping with an optimised setup. The analysis reveals successful resonance at 1.45GHz, with high Q-factors and smaller volumes, facilitating the miniaturisation of Maser cavities. Furthermore, a novel toroidal resonator is investigated via simulation.
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