Green laser pointer will be described in the next passage

Solution: Assuming the incident light intensity of the quasi-monochromatic light is much smaller than the saturation intensity, the only way by stimulated emission of radiation caused by the upper level set decay rate of the population was not comparable to other relaxation process. The inversion of the number density and light intensity has nothing to do. Reverse the particle number density of active ruby, try to calculate the small signal gain coefficient of the center wavelength at 694.3nm media. Ruby carry the work of ion the Cr2O3 molecular mass fraction was 0.05%, the absorption coefficient at the center wavelength of 694.3nm at 0.4cm-1. Center frequency of the optical absorption occurs in the media-based state E1 and the energy level E2, the energy level E2 spontaneous emission lifetime of 10-4s, the absorption lines for the Gaussian linear line width of 400cm-1. As the laser technology adopted by  green laser pointer  and blue laser pointer has been becoming more and more mature.
If the particle number density, and particle concentration in the ground state energy level E2 is empty level, Find the maximum absorption coefficient of the medium, as well as the frequency of the light through the media after the 1cm light intensity attenuation of the number of? Small-signal gain factor of the impact of media which, three, four-level system is any different? Solution: factors affecting the media, small-signal gain of the frequency of the incident light, the medium of the linear function and population inversion density. "Three-level system is higher than the efficiency of the four-level system on it, why? Solution: not necessarily. (1) For the ground state to a lower level in the laser work of the three-level system, due to the reversal of the particle Mulliken density distribution.  green laser pointer and blue laser pointer are becoming more and more popular in the market.
Will be greater than at least half of the ground state particle number of particles pumped to level up before, is about to pump the particle level up. While the particles pumped four-level system simply to be able to achieve the number of particles in the Mulliken population density inversion in the energy level distribution. So the efficiency of the four-level system is far higher than the efficiency of the three-level system. (2) for the three-level system of the ground state is not a laser lower level, due to the number of particles populations to the distribution of inversion and four-level system can match the efficiency of both systems have difficult to separate the pros and cons. Later, the reason that more and more customers would like to buy   green laser pointer    will be described in the next passage.
Three-level system as shown in the second type of laser and try to export the density of population inversion between the laser up and down level ? n and pump function of the probability of WP relationship, and draw the function curve. Here, the upper level E3 is metastable laser level E2 life is very short. Solution: three-level system of rate equations taking into account the above formula can simplify as follows: Excluding the spontaneous radiation on the medium single-mode light field contribution of the photon number can be obtained: as shown in the second types of laser three-level system, the degeneracy of each level are 1, the transition probabilities are known at each level, and laser upper and lower level pump probability ratio constant, try to export the laser upper and lower level anti- turn the particle number density ? a function of n and pump chance WP3.  green laser pointer  is used in teaching of the teacher, lecturer, presenter and business personnel and so on.