The maximum output of green laser pointer

Figure 1.3.3 indicates a four-level system of the laser energy level diagram of the working substance and the main transition process, which involved the interaction level is reduced to four, that the ground state E0, pump absorption band E3, laser transition on the lower level energy level E2 and E1, for simplicity, assume that only one pump with E3, the pump for more than one absorption band of the actual situation, as long as the laser from the absorption into the relaxation process on the level of E2 is fast, the following discussion still holds. The figure, Wp - E0 ground state per unit time on the particles are pumped into the pump with the pump on the probability of E3.  led flash light is valid in freeing lecturer from the fixed spot.
When the work material pumped by the excitation source, in accordance with Figure 1-3-3 can write the level number density of particles on the rate of change over time equation for the four-level laser system working level structure and transition material has the following characteristics : S32> S30, A30, Wp, A30> S30; A21>> S21; S10 great; E1-E0>> kT, which makes the thermal equilibrium E1 on the laser level population on the particle can be ignored. Also according to the relationship between Einstein coefficients and three inversion on the definition of the level density of the particle population on the rate of change over time to become simplified equation. Now analysis of activated l-th cavity mode photon number density φl the variation with time, set the l-th mode photon life τRL, the laser cavity length L, the work material length l, the photon number density φl time-varying rate equation. The user should notice some requirements of using green laser pointer .
Figure 1.3.4 for the three-level system laser particle energy and the work material during the main transition diagram. Involved in the interaction process can be simplified into three series, namely, pump absorption level E3, E2 level on the laser transition and lower energy levels E1, where E1 is the ground state. Similarly, suppose there is only one pump absorption band. Drawn in the figure of the transition process and the four-level similar physical meaning. Three-level system of atomic energy level structure of the laser medium and a transition process is characterized by S32>> S31, A31, Wp, A21>> S21. If the medium level in the total particle number density of particles is n, the corresponding set of particles on the energy level populations density of n1, n2, n3, medium line broadening line of g (υ, υ0) , the total photon single-mode light field number Φl, ignored medium loss of photon number and some other non-activated secondary transition process. The purchase order of green laser pointer has to be under the centralized management.
Refer to Figure 1-3-4 in the four-level use of some of the results can be obtained three-level system of rate equations as follows: Where, τ3 particle energy levels of the E3 in the life; τ31 E3 to E1 transition from the determined particles on the energy level E3 life; τ32 E3 to E2 by the non-radiative transition of particles determined by the life on the level E3; τ2 particle energy levels E2 on life. CanLet λ is the wavelength of light, L is the geometric cavity length, η is the refractive index of the work material, q take a series of integers. Will meet on the type of wavelength to λq to mark, there are usually referred to as the optical cavity standing wave conditions. Where, λq = λ oq / η as the material of the resonant wavelength, L 'is the optical cavity length. The style can also be used to indicate the frequency. The customer wants to know the maximum output of green laser pointer .
Chapter Introduction to the discussion above shows that the laser device: the cavity length L 'of resonant cavity must only satisfy (1-3-6-2) the frequency of light to form interference strengthened to form a stable harmonic oscillation. Type (1-3-6-1) and (1-3-6-2) in the FP cavity is spread along the axial plane wave resonance conditions. Satisfying (1-3-6-1) is called the cavity resonance wavelength λ the wavelength, while satisfying (1-3-6-2) as the frequency νq cavity resonant frequency. Type (1-3-6-2) shows that, FP cavity resonance frequency is discrete. By the standing wave of wave number q determined section. Usually characterized by cavity standing wave section describes the number of integer q longitudinal field distribution, known as the cavity longitudinal mode order number. Different values of q corresponding to different longitudinal modes. In the simplified model discussed here, the single longitudinal mode q value of the resonant frequency of the decision model. The certification of green laser pointer is the important checking point.