LD Pumped All-Solid-State Green Laser

A laser diode(LD) pumped solid state four-level Nd³⁺ laser with intracavity frequency-doubling has proved to be an efficient way to achieve the green laser emission and has attracted more and more attention at present.It is due to its inherent advantages,which are characterized by its high output power,high quality of laser beam and low price.In this thesis,some theoretical and experimental researches are presented and valuable results are given.Firstly,we analyze the theory of four-level system laser and obtain some parameters for optimizing the laser operation.In order to provide a good testimony for the actual work,the optimum values of the degree of mode matching of resonant light spot and pump light spot,the length of gain medium,the intracavity intrinsic loss,and the output mirror transmission have been obtained by numerical simulation.Secondly,the principle of the frequency doubling is introduced.We also introduce the influence of phase-mismatch and the ways of achieving phase-match.After comparing some crystals we choose the KTP as the frequency doubling crystal in our design and introduce its attributes.As a result,we calculate and obtain the optimization length of the frequency doubling crystal.Thirdly,the basis of the thermal lens effects and the influences of changing pump powers are studied.Using the ABCD theory to analyse the cavity,a thermally-insensitive folded cavity is designed,which overcomes thermal effects,decreases astigmatism without inserting compensators, adapts to high power LD end-pump mode.The experiment of a LD end-pumped high power intracavity frequency-doubled green laser is demonstrated.The phase-matched properties of KTP crystal are studied.Using linear cavity,we get 4.18W/532nm maximal output power.Using V-fold cavity,high efficient,high powerful and stable TEM₀₀ green laser is obtained..