Lasers (the initial letters of the English words Light Amplification by Stimulated Emission of Radiation - light amplification by stimulated radiation; synonymous with quantum generators) are devices for producing narrow beams of high-intensity light energy.
The solid-state laser circuit: 1 - and 4 - reflecting mirrors of the resonator (mirror 4 is semi-transparent); 2 - pulse pump lamp; 3 - ruby rod; 5 - capacitor; c - power source.
One of the possible schematic diagrams of the laser is shown in the figure. The basis of such a laser is a ruby rod surrounded by a gas-discharge lamp (the so-called pump lamp). The radiation of the lamp leads to the excited state of electrons in the atoms of the ruby rod. Returning to the previous state, the electrons emit energy in the form of a very narrow beam of light.
In medicine, mainly thermal, coagulating (coagulating) action of lasers is used. Devices of this kind are called light coagulators. A narrow light beam of high power makes it possible to produce tissue light coagulation in a split second.
Lasers are used in oncology (therapy of superficial skin neoplasms) and dentistry . They are also used in various studies - in histology, cytology (for operations on individual cells), etc. In ophthalmology, a laser photocoagulator is used in the treatment of certain types of retinal detachment, to prevent detachment in some types of dystrophic retinal changes.
With the help of a laser beam, it is possible to destroy small tumors in the fundus, in the iris. Photocoagulation can be used to form a hole in the iris or in a film of a secondary cataract in order to obtain a subject vision in patients.