The word "laser" and the principle of operation of this device are known to people. The closely related word "maser" is much less known. It is an abbreviation of the first letters of the words of the English definition "Microwave Amplification by Stimulated Emission of Radiation", which means "amplification of microwaves using stimulated radiation." That is, unlike a laser emitting light, a maser of a similar design emits microwave beams.
For the first time such a device was developed by Soviet and American physicists in 1954. Subsequently, scientists A. Prokhorov, N. Basov and C. Townes were awarded the Nobel Prize for this.
For a long time, the maser did not find practical application, since its operation required harsh conditions: vacuum and very low temperature (close to absolute zero). Moreover, even under these conditions, the power of the maser was much lower than the power of the laser. Recently, however, physicists at the British National Physics Laboratory have developed a model for a maser that can operate at room temperature and pressure.
Their work was based on research by scientists from Japan, who at the end of the 20th century conducted experiments by irradiating an organic compound pentacene with a laser. They found that when exposed to laser beams, the molecules of the substance can work like a maser. Since the Japanese researchers were interested in another question (neutron scattering), they did not attach importance to the discovered phenomenon. The British, having found a description of these experiments, decided to add pentacene to another organic substance to obtain crystals similar to those used in lasers. After a series of failures, crystals of the required shape and color were selected. The researchers inserted them into transparent sapphire rings, after which, placing the resulting structure in a resonator, they irradiated them with a laser. The result obtained exceeded the wildest expectations.
The laser beam brought the pentacene molecules into an excited (unstable) state. During the reverse transition of molecules to a stable state, a beam of microwaves was formed, which in intensity immeasurably surpassed the rays generated by the previous maser models. "The received signal was a hundred million times more powerful than existing masers," said physicist Mark Oxborrow, who led these experiments. The device, received by the British, is extremely promising, although it requires a lot of effort to refine. Now the Oxborrow maser generates only very short-term pulses, with a wide range of waves. If it is possible to make it work constantly, moreover, in a narrower wavelength range, the maser will find very wide application in various fields of science and technology.
