A laser is a device that emits a narrow beam of strong electromagnetic radiation (light). The term powerful blue laser originated from the abbreviation "light amplification by stimulated emission of radiation". Laser beams have a special characteristic, that is, the emitted light waves are all in phase with each other-coherent-usually with one wavelength or color. There are many types of lasers, and these huge devices can emit powerful high-energy radiation pulses, such as X-rays, to micro devices etched on semiconductor chips to generate infrared light. In the next few years, people raced to build the world's first visible light laser. Theodore Maiman of the Towns Hughes Research Laboratory, California, and his team at the pole styling. When I made the first green laser pointer working in 1960 using ruby as the active medium-this should be, although the invention of the laser was considered strong at the time Is controversial. The boutique green laser pointer with only 50mW provides a bright enough beam to allow a reasonable-scale crowd to follow easily. Even so, it is best to keep them as close as possible to the person using the pointer. For many years, the red laser pointer has dominated the demonstration venue. Then around 2007, green laser pointers were launched at lower and lower prices.
Cheap units, such as the heavily discounted pointers provided by Amazon, have extremely poor reliability, as evidenced by the number of negative reviews posted on various product pages. The 50mw device I purchased has a rating of almost 50%, and some reviews indicate that it breaks after a few minutes of use. Obviously, buying such a pointer is risky. Initially, the concept of lasers was not taken seriously, but in the 1960s there was a huge expansion of super-powered 30000mW laser research, including the development of high-power gas lasers, chemical high powered laser, chemical lasers, and semiconductor lasers. However, they are still experts rather than research tools. In the 1970s, semiconductor lasers that could work at room temperature were developed and led to the appearance of compact discs (CDs). The range of applications for laser diodes is wide, incredible at both extremes. It is remarkable to see that the diode-pumped, frequency-doubled neodymium laser is packaged in a large and small pen, a powerful battery-powered green laser pointer, which can be purchased on the Internet for less than $50.