Література

1. Квантова електроніка, М., 1969; Беннет В.,

2. Газові лазери, пер. з англ., М., 1964;

3. Блум А., Газові лазери, «Тр. інституту інженерів по електроніці і радіоелектроніці», 1966, т. 54, F 10;

4. Пател До., Могутні лазери на двоокиси вуглецю, «Успіхи фізичних наук», 1969, т. 97, в. 4;

5. Аллен Л., Джонс Д., Основи фізики газових лазерів, пер. з англ., М., 1970.

Laser

In 1953 Basov, Prohorov (Soviet physicists) and independently from them Townes (American physicist) created first molecular generators called lasers which worked in the range of centimeter waves. In 1960 Meiman (USA) created analogical device working in the optical range (Light Amplification by Simulated Emission of Radiation) – laser or optical quantum generator.

There are solids, gas, semiconductor and liquid lasers accordingly to the type of medium. Laser consists of: active medium, system of pumping, optical resonator. The scheme of laser is shown in Fig. 13.1.The active medium amplifies light. System of pumping realizes tran

Figure 23.1

sition of medium to the state with population inversion. For the selection of direction of laser radiation optical resonator is used. For example, a pair of parallel mirrors facing each other being on the common optical axis between which optical medium exists. One of the mirrors is semitransparent through which numerically amplified flux of photons laser radiation escapes.

Let us consider the work of He-Ne laser (Fig.13.2).

Figure 23.2

Population inversion of levels is realized trough electrical discharge: electrons formed in discharge excite atoms of He at collision that transfer to the state 3.

At the collisions of excited He atoms with Ne atoms excitation of them occurs and they pass to higher level situated near respective He level. Passing of Ne atoms from the high level 3 to the lower level 2 causes laser radiation of λ = 0,6328 μ. Laser radiation is characterized by:

1) High time and space coherence.

2) rigid monochromatism ( );

3) the high power of radiation;

4) very small angular discrepancy of the beam.

The use of laser is very wide: machining of materials, research of plasma, in the measuring devices, in medicine.

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