The history of lasers

In 1953, American physicist Charles Hader Townes and his student Arthur Sholow made the first microwave quantum amplifier, obtaining a highly coherent microwave beam.

In 1958, Townes and Shaw introduced the principle of microwave quantum amplifiers to the optical frequency range.

In 1960, Theodore Mayman built the first ruby laser.

In 1961, Iranian scientist AJavin et al. made a HeNe laser.

In 1962, Hall et al. created the gallium arsenide semiconductor laser.

In 2013, researchers at the National Laser Centre of the Scientific and Industrial Research Council of South Africa developed the world's first digital laser, opening up new prospects for laser applications. The findings were published in the British journal Nature Communications on August 2, 2013.

1. Laser is60s of the 20th centurynew light sources. Laser is widely used because of its good directionality, high brightness, and good monochromaticity. Laser processing is one of the most promising areas of laser application, and more than 20 laser processing technologies have been developed.

2. Development: The laser has the characteristics of good monochromaticity, strong directionality and high brightness. Thousands of laser working substances have been discovered, with wavelengths ranging from soft X-rays to far infrared.

The core of laser technology is lasers, and there are many types of lasers, which can be classified according to different methods such as working substance, excitation mode, operation mode, and working wavelength.

According to different use requirements, some special technologies are adopted to improve the beam quality of the output laser and individual technical indicators, and the more widely used unit technologies include resonance cavity design and mode selection, frequency doubling, tuning, Q switching, mode locking, frequency stabilization and amplification technology.

3. Principle: Scientists use the energy of light or current in the electric tube to hit some crystals or atoms that are easily excited, so that the electrons of the atoms reach the excited high-energy state, and when these electrons want to return to a calm low-energy state, the atoms will shoot photons to release excess energy; Then, these emitted photons will hit other atoms, excite more atoms to produce photons, triggering a series of chain reactions, and all of them will move in the same direction, forming a strong and concentrated light in a certain direction; Therefore, the strong laser can even be used to cut steel plates!

4. Characteristics: Laser is widely used because of its characteristics. (monochromatic wavelength, cohomology, parallel beams).

A laser is almost a monochromatic light wave with an extremely narrow frequency range and high energy concentration in a narrow direction, so a focused laser beam can be used to punch holes in a variety of materials. In the case of a ruby laser, for example, the total energy of the pulses is not enough to cook an egg, but it can make a small hole in a 3 mm steel plate.

The laser has the above characteristics, not because it has different light energy from other lights, but because it has a very high power density, which is why lasers are widely used.