Single-LED-pumped, room-temperature, solid-state maser

TL;DR

This paper demonstrates a miniaturized, room-temperature solid-state maser using a single LED for optical pumping, achieving enhanced efficiency and potential for compact quantum device applications.

Contribution

It introduces a novel waveguide-based optical pumping method that reduces system size and improves cooperativity in solid-state masers.

Findings

At least twofold increase in cooperativity compared to previous methods

Successful maser oscillation with a single-chip LED pump

Identification of opportunities for further optical design improvements

Abstract

Through their ability to achieve cryogenic levels of noise performance while operating at room temperature, optically-pumped, solid-state (OPSS) masers show great promise as quantum sensors, oscillators, and amplifiers. We here demonstrate maser oscillation in a microwave cavity containing a crystal of pentacene-doped para-terphenyl (ptc:ptp) pumped by a single, chip-scale LED. Here, unlike previous work, the size of the pump source does not dominate the size of the maser system as a whole. This miniaturization is achieved through invasive optical pumping in the form of a waveguide, the tip of which is embedded into the maser crystal. Using experimental measurements combined with microwave and optical simulations, we find that our approach offers at least a factor-of-2 enhancement in cooperativity over end-on optical excitation. We use our simulations to define a figure of merit for maser pumping efficiency, and conclude that there remains significant headroom to improve the performance of ptc:ptp masers through improved optical design.