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Xingbing Chao 《中国物理 B》2021,30(8):84212-084212
Owing to the unique feature that the signal and reference waves of self-interference digital holography (SIDH) contain the same spatial information from the same point of object, compared with conventional digital holography, the SIDH has the special spatial coherence properties. We present a statistical optics approach to analyzing the formation of cross-correlation image in SIDH. Our study reveals that the spatial coherence of illumination light can greatly influence the imaging characteristics of SIDH, and the impact extent of the spatial coherence depends substantially on the recording distance of hologram. The theoretical conclusions are supported well by numerical simulation and optical experiments. 相似文献
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We study transmission properties in configurations composed of two single metal gratings with different thicknesses. Choosing the perfect electric conductor excludes the influence of intrinsic material dispersion on transmission behaviors; and as such, we aim to reveal the contribution of geometric dispersion to electromagnetic transmission. Transmission suppression line, instead of a transmission suppression point, is discovered, denoting the curve of the wavelength versus the interval or the lateral displacement between the two single gratings when the transmission suppression appears. A simplified model is proposed to comprehend the underlying physics of this special phenomenon. 相似文献
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报导使用周期极化的钽酸锂超晶格(PPLT)对Nd∶YVO4晶体1342 nm谱线进行倍频获得671 nm红光的研究结果.实验所用的样品长为20 mm,周期为14.8 μm.基波为高重复频率声光Q开关的脉冲激光,获得红光最大平均功率为410 mW,晶体内基波光功率为647 mW,光-光转换效率为63%.在输出为350 mW左右时红光的波动小于3.2%.此外,在同样实验条件下未加声光开关时通过对倍频红光(CW)输出功率的测量,我们得到晶体有效非线性系数为3.8 pm/V.实验结果表明,用周期结构的光学超晶格通过准位相匹配对Nd∶YVO4晶体1342 nm谱线进行倍频, 转换效率高,系统结构简单,输出功率稳定,是获得高校大功率LD抽运的全固态红光激光输出的一条有效途径.(OC12) 相似文献
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We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ~230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ~150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged. 相似文献
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We investigate hexagonal BC2N in graphite unit cells using the first-principles method and calculate the total energies, lattice parameters, and electronic band structures after full relaxation. It is shown that stable hexagonal BC2N should be stacked sequentially with one graphite layer and one h-BN layer. The density of states indicates that this structure should have metallicity. 相似文献
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报道了利用周期极化LiTaO3光学超晶格,实现66.5%的高效倍频532 nm绿光产生的全固态激光器.波长为808 nm的半导体激光器通过光纤耦合,采用端抽运方式激发Nd∶YVO4晶体.使用的Nd∶YVO4晶体尺寸4×4×5 mm3,谐振腔的膜系保证仅1064 nm谱线共振.一重复频率为13 kHz的声光调制器置于腔内,以获得准连续的脉冲宽度约为160 ns的基频光输出.准连续基波的平均输出功率4.4 W.用焦距为50 mm的透镜聚焦后入射至长度为20 mm、厚度为0.5 mm、周期为7.69 μm的周期极化的LiTaO3光学超晶格上.晶体置于控温精度为0.1°C的恒稳炉中,温度稳定在108.8°C.在周期极化LiTaO3光学超晶格的输出端直接探测到平均功率为2.18 W的532 nm绿光输出.考虑到晶体输出面约14.2%的菲涅耳损耗,晶体内产生的绿光平均功率为2.54 W,这样在晶体内部产生的倍频绿光的转化效率为66.5%.实际上,产生绿光的转换效率更高,因为被散射的绿光也包括在内,我们探测到的是真正的有效输出.(OC21) 相似文献
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