| With the development of laser technology,an increasing demand for multi-functional laser materials attracts much interests.Self-frequency-doubling laser material is typical multi-functional material,which functions as both laser gain medium and frequency conversion material.Nd3+-doped self-frequency-doubling laser crystal could convert the near-infrared laser emission to visible waveband,which is an important method to obtain compact,stable and high-power visible laser.So far,several Nd3+-doped self-frequency-doubling laser crystals have been demonstrated for continuous-wave and passively Q-switched visible laser,including Nd:MgO:PPLN,Nd:YAB and Nd3+-doped RECa4O(BO3)3(RE=Y,La,Gd and Sm).Nd3+-doped langasite crystals with good thermal properties and stable physicochemical proterties have been proved to be excellent laser gain medium.Bulk langasite crystals could be grown by the Czochralski method with a short grown period.Nd:LGS and Nd:CNGS have been demonstrated for femtosecond laser and self-frequency-doubling laser.Based on these studies,Nd3+-doped langasite crystal Nd:Ca3TaGa3Si2O14(Nd:CTGS)with the same structure is supposed to be a potential laser gain medium and self-frequency-doubling material.Thus,the main work of this dissertation is all-solid-state laser and self-frequency-doubling laser characterizations of Nd3+-doped Ca3TaGa3Si2O14 crystal,including LD-pumped continuous-wave(CW)and passively Q-switched(PQS)laser properties at 1.06?m,CW and Cr4+:YAG PQS dual-wavelength laser properties,CW and V3+:YAG PQS laser properties at 1.3?m,CW self-frequency-doubling laser and Cr4+:YAG PQS self-frequency-doubling laser properties.Characterizations of CW and PQS lasers at 1.06 ?m and 1.3 ?m were investigated.The anisotropy of Nd:CTGS crystal were investigated,including the absorption of pump power,output power,output spectrum,laser polarization,peak power and pulse energy.It was proved that Z-cut Nd:CTGS has better CW and PQS laser performance than X-cut crystal.With a Z-cut Nd:CTGS crystal as gain medium,a CW dual-wavelength simultaneous laser was demonstrated at 1058 nm and 1065 nm.With the output coupler of 5%,a maximum output power of 3.5 W was obtained,with the corresponding slope efficiency of 39.6%.With Cr4+:YAG as saturable absorber,a PQS dual-wavelength simultaneous laser was demonstrated at 1058 nm and 1065 nm.The maximum average output power,the shortest pulse duration,the maximum pulse energy and the highest peak power were 1.6 W and 8.4 ns,45.7?J and 5.4 kW,respectively.After frequency-doubling by a KTP crystal,the second-harmonic-generation(SHG)wavelength at 529 nm and 533 nm,and the sum-frequency-generation(SFG)wavelength at 531 nm were obtained,which proved the time synchronization of 1058 and 1065 nm dual-wavelength.With ?-type and ?-type phase-matching Nd:CTGS cryatals,CW self-frequency-doubling(SFD)laser were demonstrated at 532 nm.When a plane-plane cavity structure was employed,the maximum output power was 51 mW with ?-type crystal and 26 mW with ?-type crystal,respectively.While a microchip structure was employed,the cavity length was shortened to be 12 mm(from 16 mm),and the maximum output power was increased to 109 mW with ?-type crystal and 52 mW with?-type crystal,respectively.?-type crystal has better SFD laser performance than ?-type crystal.With ?-type phase-matching Nd:CTGS cryatal,a Cr4+:YAG PQS SFD laser was demonstrated at 532 nm.When a plane-plane cavity structure was employed,the maximum output power was 30 mW.The shortest pulse duration,maximum pulse energy and highest peak power were 11.2 ns,1.4 ?J and 129 W,respectively.While a microchip structure was employed,the cavity length was shortened to be 14 mm(from 20 mm),and the maximum output power,pulse energy and peak power were increased to 69 mW,7.8 ?J and 1.01 kW.As we have known,they are the best results of diode pumped,pulsed SFD laser... |
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