green laser pointer itself should also be improved

green laser pointer  itself should also be improved
Electrons in an atom will absorb foreign energy transition from low level to high energy level, the atomic excitation. The excitation process is the "shock absorption" process. Spontaneously in a high energy level (E2), e-life is very short (typically 10-8 to 10-9 seconds), in the absence of external forces to the low energy level (E1) transition when the transition will have a light (electromagnetic) radiation . The photon energy hυ = E2-E1 of this radiation is called spontaneous emission. Atomic spontaneous emission process is a completely random process, each light-emitting light-emitting atomic process separate, unrelated, that is, the light radiation in the emission direction of the rules fired in all directions, the other initial phase, the polarization state varies. For this kind of green laser pointer has the good quality and high performance.
As the excitation level has a width, so the frequency of the light emitted is not single, but there is a range. The usual thermal equilibrium conditions in the atomic number density of N2 in the energy level E2 than in the low-level atomic number density is low, this is because of the size of the atomic number density N in the level E with the increase in the level E index decreased, the namely Nαexp (-E/kT), which is well-known Boltzmann distribution law. So in the next two levels on the atomic number density ratio. Where k is the Boltzmann constant, T is absolute temperature. E2,> E1, N2 << N1. For example, the known hydrogen atom ground state energy E1 =-13.6eV, the first excited state energy E2 =-3.4eV. The more important thing is that green laser pointer has the multiple functions.
At 20 ° C, kT ≈ 0.025 eV, is visible at 20 ° C, all hydrogen atoms are almost in the ground state to make light-emitting atoms, must be external energy atoms to the excited state, so the ordinary broad luminescence is included by stimulated absorption and spontaneous emission process. In general, the light radiated by the light energy is not strong, plus fired in all directions, and more energy-dispersive. Stimulated emission and light amplification. Know by the quantum theory of knowledge, a level corresponding to the electronic energy state. Electron energy is determined by the principal quantum number n (n = 1,2, ...). But the actual description of the atomic electrons in the state of motion, energy, as well as outside the orbital angular momentum L and spin angular momentum s, and they are quantized by the corresponding quantum numbers to describe.  green laser pointer can be used in many different locations.