共查询到20条相似文献,搜索用时 125 毫秒
1.
2.
3.
4.
佳能EF100~400mm/F4.5~5.6L IS USM镜头的开发目标 佳能EF100~400mm/F4.5~5.6L IS USM镜头是继佳能EF75~300mm/F4~5.6 IS USM(1995年9月椎出)、EF300mm/F4L IS USM(1997年3月推出)、EF28~135mm/F35~5.6 IS USM(1998年2月推出)后,作为第四代防手持晃动的单镜头反光相机交换镜头而开发的。该镜头开发目标如下: EF100~400mm/F4.5~5.6L IS USM镜头是作为EF100~30… 相似文献
5.
这是一支腾龙公司新推出的包括从广角到中焦的超高倍LD非球面(IF)微距变焦镜头,与去年推出的艺康AF28~200mm/F35~56AL(IF)以及宾得AF28~200mm/F35~56AL(IF)镜头比较,中焦段达到300mm,足足延伸了100mm。其主要特点:(1)高变倍比:107倍。(2)高清晰度:专业级像质。画面中心与边缘照度较均匀,各档光圈象质均优良。(3)小型轻量:外形尺寸804mm×936mm,重量585g。(4)调焦方式:独特的内调焦方式,最短摄影距离达到06m(… 相似文献
6.
3.2美能达AF85mm f/1.4G 这款镜头镜头号为:20801191。最大光圈F1.4,采用浮动对焦设计,圆形9瓣光圈叶片,有特宽的橡胶对焦环、焦点固定按钮。 主要性能规格 焦距:85mm光圈范围: F1.4至F22镜头组成: 6组7片视场角: 28°30’最短摄影距离: 0.85m最大摄影倍率: 0.128滤镜尺寸: 72mm外形尺寸: 78mm(最长)× 72. 5mm(直径)重量: 550g 焦距实测值为85.75mm。与标称值的相对误差为0.9%。 摄影分辨率测试条件同上,该款镜头的分辨率如表2。… 相似文献
7.
本文通过差热分析(DTA)和X射线粉末衍射(XRD)方法研究了赝二元系LiFCaAlF5的相平衡关系,该赝二元系在LiF:CaAlF5=1:1处形成一致融熔化合物LiCaAlF6,其熔点为814℃,并分别在LiF ̄LiCaAlF6和LiCaAlF6 ̄CaAlF5区域形成两个共晶体系,采用坩埚下降法生长出氟化物激光晶体Cr^3+:LiCaAlF6。 相似文献
8.
9.
尽管升华方法在除去氧化物方面很有成效,但也必须注意ZrF4和HfF4的水解温度和脱水温度.由于升华方法不能有效地除去象FeF3等氟化物杂质.作者根据FeF63-,CoF63-是属于外轨道络合物,它们是不稳定的和容易离解出Fe3+和CO3+,同时FeZrF6·6H2O也易于离解出Fe2+,以致使(NH4)3ZrF7和(NH4)3HfF7可以用DDTC-CHCl3,在pH3~3.5的有效萃取成为可能.在ZrF4-HfF4的二元组分系统中,它们的升华、凝华过程是遵循图2的相平衡规律进行的.用XRD检测升华产品,为无水单斜态的ZrF4或HfF4晶体,用GFAAS检测,升华前后Fe含量各自为0.8ppm和0.5ppm,批生产量250g. 相似文献
10.
11.
Nd3+:Y0.5Gd0.5VO4晶体生长和基本特性 总被引:5,自引:0,他引:5
Nd^3 :Y0.5Gd0.5VO4晶体作为一种新的激光材料,可以用中频感应加热提拉法生长。X射线粉末衍射分析表明它的结构与Nd^3 :YVO4晶体结构相同,它的晶格常数介于YVO4和NdVO4晶格常数之间。用ICP光谱法测定晶体中Nd^3 含量为0.8at%,分凝系数为0.8,与Nd^3 :GdVO4晶体中Nd^3 的分凝系数0.78相当;用称重法测定其密度为5.00g/cm^3;用稳态纵向热流法测出其室温热导率为12.5W/mK。实验表明Nd^3 :Y0.5Gd0.5VO4晶体有希望作为高功率ID泵浦激光晶体材料。 相似文献
12.
利用熔体提拉法生长了大尺寸,高质量的新型激光自信频晶体Nd:GdxY1-xCa4O(BO3)3简称Nd:GdYCOB).对Nd:GdYCOB晶体的XRD衍射图进行指标化,得到它的晶胞参数为α=8.080A; b=16.016A; c=3.538A; β=101.18°;μ=491.1A3.对取自不同部位的晶体粉末进行ICP原子发射光谱分析表明晶体整体组份均匀一致,根据熔体和晶体粉末的ICP数据计算,Nd:GdYCOB晶体中Nd3+的分凝系数为0.63.首次报道了 Nd:GdYCOB晶体200~3000nm室温透过光谱和室温荧光光谱及荧光寿命.室温透过光谱表明Nd:GdYCOB晶体的紫外吸收边在~220nm,具有很宽的透光波段(~220~2700nm); Nd:GdYCOB晶体在800nm附近存在很强的吸收,适合于LD泵浦.荧光光谱表明Nd:GdYCOB晶体是一种很有潜力的RGB(red;green, blue)激光自信频晶体.掺杂 4%、 5% Nd:GdYCOB晶体的荧光寿命分别为 105μs和100μs. 相似文献
13.
利用熔体提拉法生长了大尺寸,高质量的新型激光自倍频晶体Nd:GdxY1-x(Ca4O(BO3)3(简称Nd:GdYCOB),对Nd:GdYCOB晶体的XRD衍射图进行指标化,得到它的晶胞参数为a=8.080A;b=16.016A;c=3.538A,β=101.18,μ=491.1A3,对取自不同部位的晶体粉末进行ICP原子发射光 分析表明晶体整体组份均匀一致,根据熔体和晶体粉末的ICP数据计算,Nd:GdYCOB晶体中Nd3 的分凝系数为0.63,首次报道了Nd:GdYCOB晶体200-3000nm室温透过光谱和室温荧光光谱及荧光寿命,室温透过光谱表明Nd:GdYCOB晶体的紫外吸收边在-220nm,具有很宽的透光波段(-220-2700nm);Nd:GdYCOB晶体在800nm附近存在很强的吸收,适合于LD泵汪,为光光谱表明Nd:GdYCOB晶体是一种很有潜力的RGB(red,green,blue)激光自倍频晶体,掺杂4%,5% Nd:GdYCOB晶体的荧光寿命分别为105us和100us。 相似文献
14.
Chao-yu Li 《Journal of Modern Optics》2013,60(14):1323-1330
AbstractThe incident pump beam waist-dependent pulse energy generation in Nd:YAG/Cr4+:YAG composite crystal passively Q-switched microchip laser has been investigated experimentally and theoretically by moving the Nd:YAG/Cr4+:YAG composite crystal along the pump beam direction. Highest pulse energy of 0.4 mJ has been generated when the Nd:YAG/Cr4+:YAG composite crystal is moved about 6 mm away from the focused pump beam waist. Laser pulses with pulse width of 1.7 ns and peak power of over 235 kW have been achieved. The theoretically calculated effective laser beam area at different positions of Nd:YAG/Cr4+:YAG composite crystal along the pump beam direction is in good agreement with the experimental results. The highest peak power can be generated by adjusting the pump beam waist incident on the Nd:YAG/Cr4+:YAG composite crystal to optimize the effective laser beam area in passively Q-switched microchip laser. 相似文献
15.
A laser-diode-array end-pumped Nd:LuVO4 crystal continuous-wave (cw) laser operating at 1.34 microm has been demonstrated. The maximum cw output power of 1.85 W was obtained at the incident pump power of 17 W for a c-cut 0.5 at. % Nd-doped LuVO4 crystal sample, giving the corresponding optical conversion efficiency of 10.88% and a slope efficiency of 13.5%. Laser experiments of Nd3+ concentration of 0.5 and 0.9 at. % a-cut crystal LuVO4 samples were also investigated; due to the strong excited-state absorption of Nd:LuVO4 at 1.34 microm, the output power was limited. 相似文献
16.
激光非线性复合功能晶体的研究和发展 总被引:5,自引:0,他引:5
简要回顾了激光非线性复合功能晶体(即自倍频晶体)的发展过程,从结构、生长和性能等方面对现已研制发展的Nd:Mg:LiNbO3(NMLN)、NdxY1-xAl3(BO3)4(NYAB)、Cr:KTP、LaBGeO5:Nd3+、β’-Gd2(MoO4)3:Nd3+(GMO:Nd3+)、掺Nd3+或Yb3+的ReCa4O(BO3)3(ReCOB;Re=Gd、Y)(即 Nd:GdCOB、Yb:GdCOB、Nd:YCOB、Yb:YCOB)、Yb:BaCaBO3F 等几种主要类型的自倍频晶体的研究现状进行了总结,并对该类晶体的发展做了展望. 相似文献
17.
Brenier A 《Applied optics》2004,43(32):6007-6010
Idler generation from self-difference frequency mixing of the pump wave near 750 nm and the 1062-nm Nd3+ laser emission in the bifunctional laser and nonlinear optical YAl3(BO3)4:Nd3+ crystal was shown. The efficiency was 0.37%, and the infrared wavelength was tunable in the 2430-2600-nm range. New Sellmeier formulas that predict phase-matching polar angles for frequency conversion processes involving wavelengths up to 2600 nm were established. 相似文献
18.
19.
20.
We demonstrate pulse laser operation of a Pr:LiYF(4) laser pumped by InGaN laser diodes (444 nm) using an acousto-optic modulator. We obtained a maximum laser peak power of 167 W (4 μJ/pulse) with a pulse width of 24 ns at an 11 kHz repetition rate for a 63 nm wavelength. Employing an 8 mm long lithium triborate nonlinear crystal in the laser cavity, we obtained a maximum peak power of 55 W (2.7 μJ/pulse) at 320 nm, which corresponds to a conversion efficiency of 69% with respect to the fundamental laser energy. The UV laser pulse width was 36 ns. 相似文献