The manager will supervise the quality control process of green laser pointer

Cavity between two adjacent longitudinal modes of the frequency difference Δνq called longitudinal mode spacing. By (1-3-6-2) obtained: It can be seen, Δνq nothing to do with q, for certain optical cavity is a constant, thus the cavity longitudinal mode in the frequency scale is equidistant arrangement, as shown in Figure 1.3.5 below, its shaped like a comb, often referred to as "frequency comb." Each figure has a certain width of the longitudinal modes are Δνq the line that called the spectral line width. It is the internal structure of matter (electrons, atoms and other particles in orbit) is determined, the composition of the material micro-particles (electrons, atoms, ions or molecules) radiative transition occurs, the radiation wave frequency range of the spectrum width, called fluorescence line width ΔνF. The manager has some suggestion for the low power design of green laser pointer .
Where, ΔνH for the homogeneous broadening caused by the line width, ΔνI non-homogeneous broadening caused by the line width. Description of light amplification gain of the role of active substances, usually to describe the amplification factor G. In the direction of light propagation z, the light intensity I (z), defined as the gain coefficient. Therefore G (z) per unit length of said light activated by the light intensity after the growth rate of the material. Obviously, dI (z) is proportional to the active substance per unit volume of the net stimulated emission photon number. Thus, the gain coefficient G and the work material density inversion △ n is proportional to the scale factor is the emission cross-section σ21 (ν, ν0). σ21 (ν, ν0) also decided to work the material in the spontaneous radiative transition probability A21 and linear function g (ν, ν0). Where, λ0 transition for the media center of a given wavelength. The company will send a representative to supervise the incoming inspection of 200mw laser pointer.
Similarly can be defined, the absorption coefficient and dielectric absorption cross-section relationship between. Emission cross section, absorption cross section depends on the nature of the laser medium transition itself, its value can be found in the laser manual, usually refers to the peak, that is the center frequency corresponding to the cross section. Taking into account the gain and loss, there are. Assuming a weak light Is to enter an infinitely long amplifier. Initially, the light intensity I (z) will be the law of growth of small signal amplification, but with I (z) increases, G (I) will be reduced due to saturation effects and, thus I (z) of the growth will gradually slow down. When G (I) = α, when, I (z) will not increase the limit to achieve a stable Im. According to G (I) = α can be obtained, Im. Can be seen, Im only with the parameters of the amplifier itself, and has nothing to do with the initial intensity I0. The manager will supervise the quality control process of green laser pointer .
In particular, no matter how weak the initial I0, as long as the amp long enough, can be formed to determine the size of the total light intensity Im, which is actually the concept of self-oscillation. This shows that when the length of the laser amplifier is large enough, it may become a self-excited oscillator. In fact, we do not really need to activate an unlimited increase in the length of the material, as long as the optical amplification in a certain place on both ends of the laser medium section of the optical cavity. Thus, the axial wave mode will be able to form the resonator mirrors under the action of round-trip propagation in the laser medium, it is equivalent to increasing the length of the amplifier. Optical resonator of this effect is also known as optical feedback, because there is always a cavity in the activation frequency in the vicinity of ν0 weak spontaneous emission light, which after several amplification by stimulated emission of radiation, it is possible to light in the axial mode to generate self-excited oscillation of light. The preheating time of green laser pointer is very short.
This is the laser oscillator, referred to as laser. A laser can produce self-oscillation conditions, that any small initial intensity I0 can be formed to determine the size of the cavity Im light conditions, from equation (1-3-6-9) obtained. This is one of the laser oscillation conditions. Where G0 is the small signal gain coefficient, α is the included amplifier cavity loss, including loss and the total loss factor. When G 0 = α, the oscillation threshold as the situation when the cavity to maintain the intensity I0 of the initial light intensity level is extremely weak. When G0> α, the cavity has increased light intensity Im, and Im is proportional to G0. Visible, gain and loss of this contradiction is the laser oscillation becomes the determining factor.  green laser pointer can be used as the traditional teacher’s pointer.