and laser-induced breakdown spectroscopy
Tm-doped flurozirconate glass fibers are an excellent medium for solid-state lasing operations, which utilize the 3H4-3H6 transition. These fibers, however, are difficult to handle and fabricate. Thus, Tm-doped flurozirconate crystalline host materials are proposed as the ideal alternative. Unfortunately, these crystalline host materials suffer from short upper-state lifetimes and have multiplicity in their lower laser level. These combined effects ultimately increases the laser threshold.
The invention is a method for reducing the lasing threshold by increasing the upper-state lifetimes and by reducing the viability of select lower states, while still utilizing the 3H4-3H6 transition in Tm3+ doped crystalline host materials. These methods are excellent for a variety of crystalline host materials such as Y3Al5O12 (YAG), YAlO3, GdVO4, and LiYF4 (YLF). The upper-state lifetime is increased through carefully modifying the multi-phonon relaxation rate and avoiding concentration quenching. The multiplicity of lower state is resolved through increasing pumping intensity, sharpening absorption features and increasing the peak absorption strength. This laser is simple, efficient and boasts a small quantum defect, enabling excellent scalability to high average power with good beam quality.
scalability to high average power with good beam quality