The development of new instruments based on miniaturised room temperature MASERs: MASER in a Shoebox

The aim of this proposal is to develop equipment that can take advantage of the discovery of MASER action at room temperature. The MASER (Microwave Amplified Stimulated Emission of Radiation) was in fact discovered before the LASER (Light Amplified Stimulated Emission of Radiation) but required cryogenic cooling and magnetic fields. The associated infrastructure needed to operate the MASER meant that it was used in very few specialist applications such as deep space exploration. Maser research then produced lasers and around the same time, semiconductor amplifiers were developed, which brought further development to a halt. However, they were developed into very useful devices for timekeeping, radio astronomy and deep space communication (Ruby masers) because of their unparalleled low electronic noise as well as a very narrow linewidth of oscillation.

The discovery of masing at room temperature is a step change that allows us to consider new instrumentation that would transform low-noise amplifiers, sensors, and clocks. If we can amplify tiny signals and increase signal to noise then we can use them as very low noise amplifiers - these are found in all manner of electronic equipment. The gamechanger is the noise floor of our maser when measured at room temperature.
Our ambition therefore is to extend the astounding sensitivity and low noise of existing masers to room-temperature applications, there are two relevant comparators - existing non-ambient technologies and existing room-temperature technologies. For applications as low-noise amplifiers, a key figure of merit is the so-called "noise temperature" which should be as low as possible and for conventional electronic devices is approximately their thermodynamic temperature. The pentacene maser has an estimated noise temperature of 140 milliKelvin and the diamond maser has an estimated noise temperature of less than 2 Kelvin with theory suggesting the noise temperature could be lowered to around 300 milliKelvin, all at room temperature. Our noise floor is 1-2 orders of magnitude lower than the best semiconductor (high electron mobility transistors) available today. So for example we would get better images in a MRI machine or clearer communications. Already we can foresee additional applications for the re-engineered maser that include more sensitive medical scanners; chemical sensors for remotely detecting explosives; advanced quantum computer components; and better radio astronomy devices for potentially detecting life on other planets.

Our next step is to provide a miniaturised benchtop demonstrator instrument capable of addressing these applications. This is important both to allow a transition from just studying room-temperature masers into actually using room-temperature masers, and as a step towards widespread use of these devices in other research labs and in industry. It is our experience and indeed that of colleagues engaging with industrial partners, that it is essential that we provide a proof of principle instrument.