Best Burning Laser Pointer

Before scientists have created red, blue and green laser and other visible color, but also emit red, green and blue most powerful laser pointer proved to be very difficult, because of the need of semiconductor components huge difference.

Scientists and engineers at Arizona State University, the first to create a white laser, published in the Journal Nature Nanotechnology. In the paper, "Although previous studies have created red, blue, green, and other band lasers, usually each laser emits only one color of light. It is very difficult to create an integrated device that can emit red, green, and blue at the same time, because it requires a combination of different semiconductors. However, putting these mismatched crystals one by one will cause some fatal defects."

This statement is a clear explanation of why the so-called "White Laser" is very difficult to create. In fact, this sentence also illustrates the fundamental principle of the "White Laser", is simply to overcome this difficulty, several different crystal fused into a sheet, using the sheet as Gatling laser pointer material to get red, green and blue three colors, of course you can get all kinds of laser wavelength the. The real difficulty, said very clearly, not white laser to come, but we know how to create white laser (using RGB tricolor overlay, and to know how to achieve) (the three working on a material as the working substance of the laser, and the realization process of the) extremely hard, too that is to say, the three kinds of material added to a chip is very difficult.

First of all, we need to understand what is the laser, laser is how to produce. Laser, derived from Light by Stimulated of Radiation (stimulated emission of light amplification) abbreviation, laser we can understand the laser, can also be understood as the laser Emission, Amplification. The laser is mainly composed of the working substance, the resonant cavity and the pump source.

So how does the 3000mw laser pointer come into being? We know that in nature, any process of light emission must go through two stages, spontaneous emission and stimulated absorption. When the atoms are subjected to external energy, such as light energy, electric energy, etc., the electrons at low energy level will absorb the energy and then jump to the high energy level. The electronic transitions to high level, due to high energy instability, they can only stay for a short time, probably in the 10 ^ 9s magnitude will also transition to low level. There are two kinds of transition process, one is spontaneous, called spontaneous emission. Will cause two results of spontaneous emission, an emitting heat transfer to other particles, this form does not emit light, called non radiative transition; another will radiate a photon, photon frequency is extremely energy difference among decisions, this is the light.

Ordinary light source is stimulated by the absorption and spontaneous emission, the light source to accept the external energy, and then emit a steady stream of photons, so the light source will send out the light. The other is induced by external factors, called stimulated emission. Stimulated radiation will radiate a photon, but unlike the spontaneous emission, stimulated radiation will radiate two photons, the two photons, one is to meet the induced photon excitation conditions, the other is a photon electron from high level transitions to lower energy release. Unfortunately, the two photon is the two photons as like as two peas, and inspire as well as the induction conditions, to stimulate the other in high level to low level and get 4 particles, such as like as two peas photons, then the 4 becomes 8...... The burning laser produced. (in fact, the process of laser generated is very complex, there are many necessary conditions, such as through the inversion to overcome the various contradictions between shock absorption and stimulated radiation and so on, here is only briefly) in simple terms, is caused by pumping source work material particles are constantly stimulated radiation in the resonant cavity. So that the photon emitted laser accumulation.

From this process, we can clearly see the characteristics of laser. Because the stimulated emission of photons are almost exactly the same (frequency, propagation direction, the direction of vibration, etc.), so the coherence and monochromatic laser is very good. High coherence here we do not discuss, monochromatic very well, in other words, the wavelength is stable. He Ne laser frequency stabilization of a single-mode wavelength lambda = 632.8nm, and the half width of spectral line was selected can be less than 10 ^ 12 mu m, that is to say the color of delta lambda = 10 / lambda ^ 10 ^ - 10 to - 13. What is this concept? Ordinary light color best 86 krypton isotope light lambda = 605.7nm light, the half width of spectral line delta lambda = 0.47 * 10 ^ - 6 m monochromatic delta lambda = 10 / lambda ^ 6 - order, please. Secondly, we should know what is white? Generally speaking, all the light waves in the range of visible light can be stacked together to form white light.

From this point of view, the Nature Nanotechnology described the "White Laser" is not strictly white 5000mw green laser, because it does not directly send white light, but by the red, green, blue three colors of light synthesis of white light, we It can be understood as a broad white laser. In fact, from the fundamental point of view, it still produces a high monochromatic laser, but the three wavelengths of light superimposed, and synthesis of the "white light."

In general, the difficulty of thinking in this article of Nature Nanotechnology is how to overcome the difficulties of fusing three different kinds of semiconductor work materials on a small wafer (nanometer-order thickness), so that the stimulated radiation produces The photon will have three different energy, there are three different frequencies, the radiation of light will have three different wavelengths. The three wavelengths of light by superimposing each other can generate any visible light band, thus forming a "White Laser". It sounds so easy, but as the article says, blending together different work materials is a very difficult task, and together there are some fatal flaws that can make it sound easy. Of the matter until the 1000mw green laser was invented 55 years before someone successfully achieved, which is sufficient to prove the difficulty of this matter.