Laser radiation and its effects on humans
A. Einstein's brilliant prediction, which he made back in 1917, about the possibility of induced emission of light by atoms, was brilliantly confirmed almost half a century later in the creation of quantum generators by Soviet physicists NG Basov and AM Prokhorov. According to the English abbreviation, this device is also called a laser, and the radiation they create is laser.
Where do we meet in everyday life with laser radiation? Nowadays, lasers are widely used - these are various fields of technology and medicine, as well as lighting effects in variety shows and shows. The beauty of iridescent and dancing laser beams made them very attractive for home experimenters and laser gadget manufacturers. But how does laser radiation affect human health?
To deal with these issues it is necessary to recall what laser radiation is. To do this, we "transfer" to physics lesson in grade 10 and talk about quanta of light.
What is laser radiation?
The ordinary light is born in atoms. Laser radiation - the same way. However, in other physical processes and as a result of the external electromagnetic field. Therefore, the laser radiation is forced (stimulated).
Laser radiation is electromagnetic waves that propagate almost parallel to each other. Therefore, the laser beam has a sharp directionality, an extremely small scattering angle and a very significant intensity of action on the irradiated surface.
What is the difference between the radiation of a laser from, for example, the radiation of an incandescent lamp? The incandescent lamp is a man-made light source emitting electromagnetic waves, unlike laser radiation, in a wide spectral range with a propagation angle of about 360 degrees.
The effect of laser radiation on the human body
The possibility of extremely diverse application of quantum generators, prompted specialists in various fields of medicine to deal with the impact of laser radiation on the human body. It was found that this type of radiation has the following properties:
when working with laser radiation sources, damaging factors can be either direct (from the installation itself) or scattered, as well as reflected radiation;
- the degree of damage depends on the parameters of the electromagnetic wave and the localization of the irradiated tissue;
- absorbed by these tissues energy can cause a number of negative effects - thermal, light, etc.
The sequence of damage in the biological effect of laser radiation is as follows:
- a sharp increase in temperature accompanied by a burn;
- followed by effervescence of the interstitial, as well as the cellular fluid;
- the resulting vapor creates enormous pressure, resulting in an explosion and a shock wave that destroys the surrounding tissue.
At small and average intensities of irradiation skin covers are especially affected. With a stronger effect, the lesions on the skin look like edema, hemorrhages and necrotic areas. But the internal tissues undergo significant changes. And the greatest danger comes from direct and specularly reflected radiation. It also causes pathological changes in the work of the most important systems of the body.
Particularly we will dwell on the effect of laser radiation on the organs of vision.
The short radiation pulses generated by the laser cause severe damage to the retina, the cornea, the iris and the lens of the eye.
There are 3 reasons for this.
- During such short time intervals of the pulse duration (0.1 s), the defensive blinking reflex does not have time to work.
In addition, the cornea and the lens of the eye are extremely vulnerable organs.
- A negative contribution to the damage to the organs of vision is also made by the optic system of the eye, focusing laser radiation on the fundus. The point of laser radiation, which has got on the retinal vesicle, can clog it. Since there are no pain receptors, the damage to the retina is invisible at first. But, when the region burned by the laser beam becomes large enough, the images of objects that have fallen onto it disappear.
Characteristic symptoms in the defeat of the eyes are spasms and edema of the eyelids, pain in the eyes, clouding and hemorrhage of the retina. After damage, the cells of the retina are not restored.
The intensity of radiation, which leads to damage to the organs of vision, is lower than radiation, which causes damage to the skin. Any infrared lasers, as well as devices that emit visible light with a power of more than 5 mW, can be a hazard.
Dependence of the effect of laser radiation on a person on its spectrum
Remarkable scientists of different countries, working on the creation of a quantum generator, could not foresee what wide use their child will find in various spheres of life. But each of these areas will require specific, specific wavelengths.
Why does the wavelength of the laser radiation depend? It is determined by the nature, more precisely, the electronic structure of the working body (the medium where this radiation is generated). There are various solid-state and gas lasers. These miracle rays can belong to the ultraviolet, apparently (more often red) and infrared regions of the spectrum. Their range is within the limits of 180 nm. and up to 30 microns.
The nature of the effect of laser radiation on the human body largely depends on the wavelength. Our vision is about 30 times more sensitive to green than to red. Therefore, we will respond to the green laser faster. In this sense, it is safer than red.
Protection from laser radiation in production
There is a huge category of people whose professional activities are directly or indirectly related to quantum generators. For them, there are strict regulations and standards for protection against laser radiation. They include measures of general and individual protection, depending on the degree of danger that this laser installation represents for all structures of the human body.
In total there are 4 classes of danger, which the manufacturer must specify. Danger to the human body are lasers 2,3 and 4 classes.
Collective means of protection against laser radiation are protective screens and casings, light guides, television and telemetric tracking methods, signaling and blocking systems, as well as fencing the area with radiation exceeding the maximum permissible level.
Individual protection of employees is provided by a special set of clothes. For eye protection, it is mandatory to wear glasses with a special coating.
The best prevention of laser radiation is compliance with the rules of operation and protection, as well as timely medical examination.
Protection against laser radiation for users of laser gadgets
Uncontrolled use of home-made lasers, lamps, light pointers, laser flashlights carries a serious danger to others. To avoid tragic consequences, one should remember:
- "Games" using lasers are permissible only where there are no strangers;
- very dangerous rays, reflected from the glass, buckles and other objects;
- a ray of even low intensity, hitting the driver's eyes, the sportsman, the pilot of air transport - can cause a tragedy;
- Store laser gadgets in a place inaccessible to children and adolescents;
- It is possible to direct rays to the sky only at low clouds, since there is no air transport at these heights;
- it is absolutely unacceptable to look into the lens of the laser radiation source;
- safety goggles must correspond to the wavelength of the laser radiation.
Quantum generators and any laser gadgets pose a potential threat to their owners and others. And only careful observance of security measures will allow you to enjoy these achievements without harm to yourself and your friends.