Solid-State Laser At 1.44μm And The Application In Difference-frequency Generation

Laser at eye-safe wavelength of 1.44μm is strong absorbed in water and can output middle-infrared laser as a pump souse in difference-frequency generation. So it was widely used in production, medical, pollution monitoring and military. The Nd:YAG as a normal solid-state laser in near-infrared has well developed. The main working wavelength of Nd:YAG is 1.06μm, it also exists transition at 1.44μm.In order to generate 1.44μrn with Nd:YAG, this paper has researched the basic theories, designed the experiment projects, analyzed the experiment results and introduced the application of 1.44μm laser in the DFG. The main results obtained here can be summarized as follows:1. The energy level configuration and spectrum characteristic of Nd:YAG crystal on the transition of 1.44μm are analyzed.The different emission cross sections between 1.44μm and other transition are compared. We also construe the difficulties and the key technologies in generating 1.44μm laser. The NdrYAG laser system of 1.44μm are whole designed.2. Theoretically analyze the working characteristic of Nd:YAG using four-level system velocity equation. The research contents include the working threshold, the mechanism of energy transmission, the laser output and the Q-switch. We also analyzed the loss in the cavity of 1.44μm Nd:YAG laser and provided theoretical instruction for the next experiment.