采用紧凑的直腔设计和精确的膜系设计，实现了LD侧面泵浦1 110 nm Nd：GGG和腔内倍频的555 nm激光。当泵浦功率为168 W时，得到了25.5 W的1110 nm连续激光输出。在10 kHz的声光调Q情况下，应用II类非临界相位匹配LiB3O5(LBO)倍频晶体，得到了最大输出功率为3.1 W的555 nm倍频光输出，光-光转换效率为1.8 %，相应的脉冲宽度为176 ns，在水平和竖直方向上的M2因子分别为19.6和21.3。

Considering some necessary factors in the design of SSHCL, material properties of Nd doped glass, YAG and GGG were compared. Transient temperature fields and thermal stress in these slab mediums during one working cycle were simulated. Numerical analysis results showed that the internal external temperature difference in a neodymium doped glass slab was 75 K and the peak temperature value was 400 K when pumping time arrived 5 s. The maximum stress came to 50% of glass fracture limit. During subsequent water cooling period, the initial state was recovered after 120 s. On the same boundary conditions, Nd:YAG and Nd:GGG slabs could maintain relatively smooth temperature profile while the temperature rising and equivalent thermal stress were lower compared to glass. In later cooling phase, both of them could reach their operating commencement within 30 s. As cooling, the maximum stress of Nd:YAG overran 50% of the stress limit, thus increasing its tendency to fracture. Taken cooling time, fracture limit and obtainable size of the crystal into account, Nd:GGG should be the suitable active medium for high average power, repetitive frequency heat capacity laser.

The three-dimensional (3D) pump intensity distribution in medium of the laser diode (LD) pumped high average power heat capacity laser is simulated by the ray tracing method, and the divergence characteristics of fast axis and slow axis of LD are simultaneously considered. The transient 3D temperature and stress distributions are also simulated by the finite element method (FEM) with considering the uneven heat source distribution in medium. A LD face-pumped Nd:GGG heat capacity laser is designed. The average output power is 1.49 kW with an optical-optical efficiency of 24.1%.

针对Nd:GGG激光器,介绍了荧光寿命测试原理,设计了低频窄脉宽荧光寿命测试系统.该系统由光源、光路系统、驱动电路和探测系统等几部分组成.利用脉冲取样技术测试了Nd:GGG晶体的荧光寿命约为250μs左右.

考虑固体热容激光器对工作介质的要求,对比分析了掺钕的玻璃、YAG和GGG的多种材料性能.并对三者在激光工作周期内的瞬态温度场及热应力进行了数值模拟.结果表明:在给定的边界及工作条件下,当钕玻璃激光器以热容方式工作,时间为5 s时,介质最高升温超过400 K,最大热致应力为25 MPa,接近其断裂极限的50%.在此条件下进行冷却,当水温为283 K时,需经过约120 s才基本恢复到初始工作状态.而Nd:YAG和Nd:GGG两种介质在相同输入工作条件下,工作时间可达10 s,且温度分布相对平坦,温差和热应力较小,经水冷约30 s可恢复到初始状态.但模拟计算中,发现Nd:YAG在冷却阶段的最大应力达77 MPa,已超过断裂阈值下限值的50%.兼顾冷却时间、材料所能承受的应力及晶体生长尺寸,以及实现100 kW的平均功率输出等因素,Nd:GGG晶体是目前三者中比较适合于作为高平均功率、重复率热容方式工作的激光材料.

用于固体热容激光器(SSHCL)技术的掺钕钆镓石榴石(Nd:GGG)晶体要求有较大的尺寸和较高的光学质量,平界面生长是获得大尺寸和高质量Nd:GGG晶体的主要途径。采用自动控制晶体直径的单晶炉和平界面生长技术生长大尺寸Nd:GGG晶体,获得了直径75 mm,等径长60 mm以上无散射颗粒、光学均匀性好的Nd:GGG晶体。

考虑温度大幅度变化对工作介质比热容的影响,在激光二极管阵列峰值抽运功率超过104 W的情况下,对热容激光器片状18 mm×18 mm×10 mm Nd:GGG工作介质进行了温度分布的数值计算,并与HR-2型红外热像仪对工作介质端面与侧面测量的温度数据进行了对比分析,取得了一些有价值的结果。

Nd:GGG晶体是热容固体激光器的一种重要的工作介质.采用提拉法沿〈111〉方向生长出直径为60 mm的Nd:GGG单晶,利用应力仪、偏光显微镜和环境扫描电子显微镜及化学腐蚀等仪器和手段,对晶体的宏观和微观缺陷进行了观察和分析,可为改善生长工艺、生长大尺寸优质Nd:GGG晶体提供指导.

采用共沉淀方法,以金属Ga和Gd2O3为起始原料,以氨水为沉淀剂,制备了GGG多晶.测量了共沉淀方法制备的GGG多晶、固相反应法制备的Nd:GGG多晶以及提拉法生长的GGG、Nd:GGG晶体的X射线衍射谱(XRD),利用图解外推法计算了晶格参数.共沉淀方法制备的GGG多晶原料较固相法制备的Nd:GGG晶格参数小,可能是固相制备过程中Ga组分挥发导致Gd3+取代了Ga3+位以及Nd3+占据了部分的Gd3+位,从而使晶格参数变大.同时就提拉法生长的Nd:GGG晶体和GGG晶体的晶格参数进行比较发现,Nd:GGG晶体的晶格参数较纯GGG晶体的晶格参数大,说明在Nd:GGG晶体中Nd3+占据了部分的Gda+位.另外,晶体的晶格参数较多晶粉末的晶格参数大,分析认为这可能也是由于Ga组分的挥发导致Gd3+占据了Ga3+位所引起.这些实验?峁得鱃a组分挥发在原料制备过程和晶体生长过程中都可能存在,因此应在制备原料和晶体生长等各个环节中考虑Ga组分的挥发.采用液相共沉淀方法制备有利于抑止Ga组分的挥发.

研究了直接在Nd:GGG工作介质,以及在光色心晶体LiF:F-2介质中补偿辐射位相和偏振畸变的可能性.确定了使用置有LiF:F-2晶体被动开关的萨里亚克干涉仪不仅能够提高激光脉冲的稳定性和功率,而且可压缩振荡光谱.可达到的脉冲序列能量为7J、单脉冲最大功率50KW、空间亮度5×1010W·cm-2·sr-1,相干长度大于13m.