As we all know, any kind of light emission is related to its state of motion of material particles within. When the particles (atoms, molecules or ions) in the low-energy level of absorption of external energy (light) of the appropriate frequency to be excited (stimulated absorption) transition to the corresponding energy level is always trying to transition to a lower level go, the excess energy released form of a photon. Without external photon effect alone released spontaneously (spontaneous emission), then release the light is the ordinary light (such as lights, neon signs, etc.), which is characterized by the size of the frequency of light, the direction and pace of very inconsistent. Therefore, when using green laser pointer , it can work normally.
But if it is under the direct role of foreign photon transition to low energy levels by the high energy level, the excess energy released form of a photon (stimulated emission), the photon is released outside the incident photon frequency, phase, direction of propagation exactly the same, which means that the external light has been strengthened, which we call optical amplification. Obviously, if adopted by the shock absorption, so that the number of particles in a high energy level more than at the low levels of (inversion), the magnification of this optical phenomenon is more obvious, then there is likely to form the laser. The laser is labeled the magic of light, because it is the ordinary light do not have any of the four features. The customer can use green laser pointer to realize the freedom of not being restricted by the computer.
Good direction - ordinary light source (sun, incandescent or fluorescent) light-emitting in all directions, the direction of the laser light can be limited to less than the solid angle of several milliradians, which makes the illumination in the irradiation direction to improve thousands of times. Laser collimation, orientation and distance measurement is to use a good direction this feature. - Laser brightness of the brightest light source, only the hydrogen bomb explosion instantly intense flash can be comparable to it. The brightness of the sunlight is about 103 W / (cm 2 steradian), a high-power laser output brightness of the sunlight of 7 to 14 orders of magnitude higher. Thus, even though the total energy of the laser is not necessarily great. The length of green laser pointer is not very long.
However, due to a high concentration of energy, it is easy to generate high pressure and tens of thousands of degrees Celsius in a tiny point or even millions of degrees Celsius. Laser drilling, cutting, welding and laser surgery is to use this feature. Monochromatic - the light is an electromagnetic wave. The color of light depends on its wavelength. Ordinary light source light emitted typically contain a variety of wavelengths, the mixing of the various colors of light. Sunlight contains red, Tang, yellow, green, green, blue, purple seven colors of visible light and infrared light, UV and visible light. The wavelength of a laser, only concentrated in a very narrow spectral band or frequency range. Such as helium-neon laser wavelength of 632.8 nm, the wavelength range of less than one ten thousandth of nano. The infrared light cannot penetrate the object so that the visible transmission is needed for this kind of green laser pointer.
Monochromaticity of the laser, for precision instruments to measure and motivate some chemical reactions and other scientific experiments provide a very favorable means. Good coherence - interference is a property of the wave phenomena. Laser-based, highly directional and monochromatic features, it is bound to the excellent coherence. This feature of laser holography to become a reality. - The so-called laser technology, is to explore these features to develop a variety of laser and explore the application of laser technology general benefit of mankind. Since 1960 the United States successfully developed the world's first ruby laser, China has also been successful domestic first ruby laser was developed in 1961. green laser pointer only has the single laser function.
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