5. Applications
5-3. Excitation of Solid-State Laser by LD
Excitation of solid-state laser by LD can be accomplished by two methods shown below in Fig. 4 and Fig. 5.
The end excitation method achieves excitation by converging output light from the laser diode on the end of the solid-state crystal, making it possible to obtain high-quality single-frequency laser emission whose laser emission threshold value is low.
The side excitation method is used for excitation by converging the output light from the laser diode on the side of the solid-state crystal. It is suited for use in obtaining large output laser oscillations.
Development and practical use of LD excited solid-state lasers, which began with Nd: YAG, are now evolving in the following directions as well.
- Development of crystals suitable for LD excitation
Crystals such as YVO4 with a wide light absorption band
- Production of larger output by side excitation method
Larger output by use of flat plate, larger aperture diameter, etc.
- Generation of higher harmonics by non-linear optical crystals
Nd: YAG (1.06µm) and KTP combined to produce 530nm green laser with SHG
- Development of various emission operations
Optical modulation elements are inserted into resonators to have various emission operations performed by the Q switch method or mode lock method.
