The main question that is being answered today is: who invented the laser? It also provides a brief theoretical justification and reasons for creating such a useful device.
Laser application
Modern life is unthinkable without the small beams of coherent radiation that the laser generates. Its creation led to a revolution, primarily in the information sphere. Previously, data had to be applied directly to the surface of some material - paper, clay, stone. Now, any text, formula, or table fits on a very small piece of the optical disk. To the one who invented the laser, we owe modern methods of transmitting educational and scientific information, communication, entertainment and travel. Writing and reading letters and numbers no longer requires the direct participation of the human eye, a laser drive does this for people.
The device itself is also used in many other activities:
- for cutting wood, iron, plastic in production;
- for welding materials among themselves;
- for drawing symbols and signs on metal parts;
- for surgical operations.
The advantages of using this technology are undeniable. Let us tell you what theoretical and practical difficulties the inventor of the laser encountered.
Theoretical basis
At the beginning of the twentieth century, quantum physics gave impetus to the study of the microworld. For example, by the mid-fifties, electron cloud configurations of all available chemical elements were known. Scientists were able to calculate the wavelength of a photon formed by any transition. Among other great discoveries, Einstein predicted the phenomenon of stimulated emission: an electron is in an excited state, a corresponding photon flies past and “forces” an electron to go to a lower level, even if its lifetime has not yet ended. A peculiarity of this phenomenon was an amazing fact: the second photon will be identical to the first. To get a stream of identical particles was very tempting. But it was necessary to solve a number of practical problems.
The path to creating the first device
It is easy to say unequivocally who invented the laser. It was Theodore Harald Maiman, a physicist from Los Angeles. He was the first to demonstrate a working prototype on an artificial grenade. However, before him, other scientists have done a lot:
- A. Einstein in 1916 predicted stimulated emission.
- P. Dirac, in a theory developed in 1927-1930, mathematically described the possibility of stimulated emission.
- R. Landenburg and G. Kopfermann in 1928 confirmed the existence of stimulated emission experimentally.
- V. Fabrikant and F. Butaev in 1940 suggested that a level with an inverse population of electrons will help to increase the stimulated electromagnetic radiation.
- A. Castler in 1950 proposed creating an inverse population using optical pumping. For this he received the Nobel Prize.
- N.G. Basov, A.M. Prokhorov, C. Townes in 1954 demonstrated an ammonia microwave generator. They added positive feedback in the form of a resonator. This achievement also brought scientists a Nobel Prize.
- T. Meiman in 1960 finally introduced the first device based on an artificial ruby doped with chromium.
Thus, to say that the one who invented the laser in 1960 did it alone is not entirely true.
Technical obstacles to the invention
According to one well-known joke, theoretical physicists spend very little equipment. They only need paper, a pencil and an eraser. But the phenomena predicted by them require confirmation in practice. This is often very difficult. For example, to confirm the presence of gravitational waves could only in the XXI century, although Einstein suggested their presence at the beginning of XX. The inventor of the laser and its predecessors solved the following technical problems:
- Search for materials with inverse level populations.
- Selection of stably working sources for optical pumping.
- Crystal growth with desired optical properties for the laser working fluid.
- Drawing on the ends of the crystal sputtering with a given reflection coefficient to create an optical resonator.
At the moment, all these tasks are being successfully solved and do not present any difficulties for scientists.
Laser and space
As soon as all the difficulties were left behind, and the devices firmly entered into everyday life, mankind's knowledge of space expanded tenfold. If you recall in which year the laser was invented, it will immediately become clear why the space program of many countries began to develop so actively in the 1960s. In addition to a significant reduction in the weight of the equipment due to semiconductor and laser devices, the spectral purity and coherence of the generated beams helped to improve our knowledge of the space surrounding the Earth. Thanks to modern devices, scientists now know exactly the composition of all the planets, asteroids and comets of the solar system. Also, methods for determining the distance to stars and galaxies are now much more accurate. And the potential for laser applications is endless.