Since ancient times, people have believed that light carries a huge and mysterious power. With the discovery of radio, laser pointer and radioactivity, interest in radiation began to double in the early 20th century. The entire spectrum of radiation is opened, with wavelengths longer or shorter than light. What amazing new uses might be discovered in medicine, communications, scientific research or war?
Because it is so parallel, it can also be focused to a very small diameter, making the concentration of light energy so large that you can use the beam to cut, drill or rotate. It can also illuminate and inspect very small details. This attribute is used in surgical instruments and CD players.
It can also be made very monochromatic, so that there is only one wavelength of light. This is not the case with ordinary light sources. White light includes all colors in the spectrum, but even colored light (such as red LEDs (light emitting diodes)) includes continuous red wavelength intervals. On the other hand, in terms of energy content, laser engraver emission is usually not very strong. The very powerful laser used in laser shows does not emit more light than ordinary street lights. The difference is the degree of parallelism.
Radio was quickly put into use, but the same technology could not be used for shorter wavelength radiation. A method of amplifying light originated from an idea proposed by Einstein in 1916. After studying the new theory of quantum physics in depth, he predicted that rays can excite atoms to emit more rays of the same wavelength. But engineers know almost nothing about how to manipulate atoms. For decades, this idea seems to have little practical interest in theory.
Scientists and engineers are pushing radio technology to shorter and shorter wavelengths. In the 1930s, some people hoped that they were about to create a "death ray." Facts have proved that this is not feasible, but this effort has brought better results-radar. By 1940, sophisticated equipment could produce rays with a wavelength of one centimeter or less. They were quickly sent to scout the enemy plane.
As far as light is concerned, the wavelength determines the distance from short ultraviolet to visible light, and the wavelength drops from about 400nm-800nm to infrared above 800nm to above 4000nm. The blue laser pointer is usually 450nm, and the green laser pointer is usually 532nm. It is also the brightest color that the human eye can see in the visible light spectrum, which includes all existing colors. The color of the blue laser pointer has no effect on the heat output, so the high-power combustion laser can use any visible color or invisible IR and UV wavelengths.