Composite Structure Laser Materials

Laser material is the key and fundamental component for the development of laser technology. It is important for large energy and high power solid-state laser. In order to achieve lager energy, high power, and high beam quality of the laser output, the large size, high doping concentration, high heat conductivity, and low loss of laser materials are necessary. The high gain and large diameter laser of laser materials pumped by LD would lead to the serious ASE effects. Due to the quantum efficiency of laser is<1, it would lead to thermal effects. At present, For high power, high efficiency and high laser beam quality solid state laser system the two deleterious problem are thermal effect and ASE (amplified spontaneous emission). Researchers have revealed that composite materials can reduce the thermal effects, increased the output power and improve beam quality.In order to reduce the thermal load and ASE effects, we designed and fabricated the transition metal doped alumina ceramics edge cladding sapphire and composite Yb:YAG/YAG and Yb:LuAG/LuAG. The microstructure and optical properties were investigated.1. Al2O3 ceramic tape are produced by an aqueous tape casting methodIn this experiment, the slurry of Zeta-pH relation, rheological curve, binder dosage, the quality and microstructure of green tape, microstructure and optical property were studied. The results shown that the highest density of Al2O3green tape was produced by lwt% PAA dispersant and 10 vol.% PVA124. The transmittance curves of the 10vol.% PVA124 Al2O3 ceramics was ?30% in the range of 300-850 nm.2. Edge cladding of sapphire by transition metal doped alumina tapeThe green tape of Co:Al2O3 ceramic was produced by tape casting method. The materials exist a wide absorbed peak at 800nm. The absorption coefficient of materials is 1.335cm-1. The refractive index of materials is 1.768. The edge cladding of composite materials was sintered by traditional ceramic sintering. When the sintering temperature is 1750?/10h, there are much pores in the composite area; when the sintering temperature is improved to 1810?/10h, there are no pores and defect in the composite area.3. The preparation of Yb:LuAG/LuAG and Yb:YAG/YAG composite materialsDiauxic growth and microstructure of grain interfaces of Yb:LuAG/LuAG ceramic made by thermal bonding are studied. The grain growth of composite area was discussed by diffusion theory. This composite ceramic was measured by ZYGO. The results show that there are no obvious pores and no space transition layer in bonding area. The Yb:YAG/YAG composite materials were produced by thermal bonding. The grain interaction of ceramics and single crystals were studied with different sintering temperature. The results show that increasing sintering temperature or prolonging sintering time, the single crystal moved into the ceramic structure and formed the "new materials". Increasing sintering temperature or prolonging sintering time would improve more area of the "new materials". A lot of pores in the composite area come from the internal ceramics.