Room Temperature, Earth's Field MASER

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The work we propose in this research is to construct a MASER that can work at room temperature and in the Earth's magnetic field.The MASER (Microwave amplification by the stimulated emission of radiation) is in fact the forerunner of the LASER and was discovered around 50 years ago by Townes, Basov, and Prokhorov who shared the 1964 Nobel Prize in Physics for this work. A LASER can be thought of simply as MASER that works with higher frequency photons in the ultraviolet or visible light spectrum whereas a maser works at microwave frequencies. Both systems rely on a chemical species with an excited energy-level population being stimulated into lower energy levels, either by photons or collisions with other species. Photons are then emitted by the atom or molecule, in addition to the original photons that entered the system. The photons entering the system stimulate the emission of further photons of the same frequency, meaning that a strong beam of monochromatic radiation is produced. Originally the laser was seen as a good idea looking for an application. They were made in small numbers and at one point the US government decreed that every laser should be stamped with a number for military and security purposes - an idea that soon lost its appeal when the market potential for the quantities of the devices became apparent. Today lasers are made in their billions and have found their way into applications in all sectors of industry from DVD players to laser eye surgery. Masers on the other hand are used only in very specialised applications such as atomic clocks and as amplifiers in radiofrequency telescopes. Masers were responsible for the stunning images of the solar system sent by the Voyager spacecraft. So why have masers not been widely applied? There are two key reasons. First masers need cryogenic temperatures and this means the use of either cryogenic liquids or special fridges. Second, they need high magnetic fields and this means the use of bulky magnets that need high power and usually cooling with water, if an electromagnet, or with helium, if a superconducting magnet. This research is aimed at producing a maser that will operate at room temperature and in the earth's magnetic field. This is of course an extremely ambitious project but it is borne out of research in some of the materials that will be used in the project and these are the very high Q resonators. Work on high Q resonators has been carried out by the group for several years and now it appears that a solid state maser can be made using a high Q resonator and quite a low power. Our initial scouting experiments have shown that it is indeed possible to achieve masing at room temperature and earth's field in pulsed mode. The research that will be carried out will explore new materials that will miniaturise the maser and require very low power to achieve the threshold required for masing.