Passively Q-Switched Microchip Laser Based On Cr4+:YAG Crystal

With the continuous development of laser technology,tuning Q laser application is more and more widely.Laser diode pumped Cr4+:YAG passive tuning Q all solid of the state laser is widely used in recent years,as a passive tuning Q laser,which has small volume,all solid state,the higher efficiency energy conversion,a stable performance for the output,etc,and Laser diode pumped Cr4+:YAG passive tuning Q all solid of the state laser can output laser pulse with the narrow pulse width,high repetition rate,high quality laser pulse peak power,more than for its excellent characteristics in laser ranging,remote sensing detection,medical apparatus and instruments,and military and civil communications developed a broad prospects in the areas of application,and the status of the laser diode pumped Cr4+:YAG passive tuning Q all solid of the state laser in this field has been more and more heavy.This paper traces the LD pumped solid state laser and the representative of the LD pumped Cr4+:YAG passive tuning Q laser,which has a widely development and the practical application for the Laser diode pumped and in this paper,we also research the proprietary technology applied to production,which also include the status of Laser diode pumped Cr4+:YAG passive tuning Q all solid of the state laser from home and abroad,which also including the coupling technology which is currently used for the research of the LD pumped Cr4+:YAG passive tuning Q laser and the heating technology,etc.And we detailed introduce the theoretical basis and implementation requirements of tuning Q laser application,respectively,introduces several different ways of tuning Q.In general,usually adopt the method of modulation resonator loss to modulated laser resonant cavity Q value.Passive and active tuning Q nowhere,to rely on oneself change of saturable absorber is to control the state of Q switch,the saturable absorber are placed in the lens of the laser cavity and work material,use this on a particular light saturated absorption effect to control the wastage of the cavity.Take the initiative to adjust Q way of Q switch controlled by external precision,can accurately control the Q time according to their own characteristics.Passive tuning Q laser can design of simple and compact structure,and saturated absorption material is growing in the same crystal with the work material,greatly reduce the volume,the whole system easier for miniaturization design,easy in operation and maintenance.We will analyze the active and passive adjustable tuning Q laser application.Detailed introduce the Cr4+:YAG crystal from the style of the basic properties,spectral characteristics and level structure for the energy and Cr4+:YAG saturable absorption characteristics.Combined with Cr4+:YAG and Nd3+:YAG energy transition and the basic principle of tuning Q laser,using the theory of rate equation of Cr4+:YAG passive tuning Q laser dynamic characteristics for the description of the system analysis,and related parameter expression is given.By analyzing the Nd3+:YAG laser Cr4+:YAG passive tuning Q rate equation,based on the theory of it,according to the actual values are numerically simulated,by R2011b Matlab software simulation,respectively for continuous pump and pulse LD pumped in both cases the Nd3+:YAG laser output characteristic to carry on the simulation analysis.To optimize tuning Q laser,it is necessary to optimize the parameters of laser performance modeling,establish objective effective laser rate equations can be comprehensive performance characterization of laser parameters,the equations of the main analysis of laser cavity photon number,the number of atomic energy level changes,the system of equations with laser cavity photon number and the work material change the atomic number of the relevant energy levels,according to the changes of the time constitute a system of differential equations,by establishing a system of equations,can effectively analyze the running characteristics of laser,through optimized design equations for Q laser,can guarantee the output performance of passive tuning Q laser.Simulation analysis of LD continuous pump of the situation,according to the passive tuning Q rate equation to establish simulation model of generation into the pump rate,initial transmittance and output mirror reflectivity and related physical quantities are numerically simulated,the simulation output pulse tuning Q,research and analysis of relevant factors in the cavity and pump rate of change of output pulse peak power,pulse width and pulse time.Analyzed in pulse pump,pump rate,pump pulse width on the pulse time,peak power,pulse width,pulse interval,etc.Tuning Q pulse output characteristic is obtained by the simulation in a cycle of pulse number and pulse time,parameters such as peak power,the time interval and pump rate,pump width and output mirror reflectivity and Cr4+:YAG crystal initial transmittance,the relationship between the external conditions,such as in the final analysis in the process of the pulse forming with the function of main boot Nd3+:YAG work material changes of the inversion of particle Numbers,and combined with Cr4+:YAG crystal passive tuning Q in the ground state changes of the number of particles,a comprehensive comparison and analysis,and summarize analyze pulse laser pump case switch each parameter Q synchronous effect of single pulse and pulse output characteristics.This paper,the simulation analysis through the results for the laser diode pumped Cr4+:YAG passive tuning Q laser design optimization has certain reference significance.