【摘 要】
：
An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging. In this paper, we report a digital micromirror device (DMD)-based ultrafast pulse shaper, i.e., DUPS
【出 处】
：
JournalofInnovativeOpticalHealthSciences
论文部分内容阅读
An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging. In this paper, we report a digital micromirror device (DMD)-based ultrafast pulse shaper, i.e., DUPS, for femtosecond laser arbitrary amplitude shaping—the first time a programmable binary device reported to shape the amplitudes of ultrafast pulses spectrum at up to 32 kHz rate over a broad wavelength range. The DUPS is highly efficient, compact, and low cost based on the use of a DMD in combination with a transmission grating. Spatial and temporal dispersion introduced by the DUPS is compensated by a quasi-4-f setup and a grating pair, respectively. Femtosecond pulses with arbitrary spectrum shapes, including rectangular, sawtooth, triangular, double-pulse, and exponential profile, have been demonstrated in our experiments. A feedback operation process is implemented in the DUPS to ensure a robust and repeatable shaping process. The total efficiency of the DUPS for amplitude shaping is measured to be 27%.
其他文献
A new multi-focus image fusion method using spatial frequency (SF) and morphological operators is proposed. Firstly, the focus regions are detected using SF criteria. Then the morphological operators are used to smooth the regions. Finally the fused image
在海洋专业组会议上，海洋波浪的观测被列为重要课题。已经采用立体照片来描述波高的图形，使用浮标式波高计测量波浪，并进一步计划用航空机载丰动式传感器来观测波浪。美国、加拿大等国正使用激光外形仪进行波浪和冰的观测。在本组会议上研究了包栝激光在内的各种测量方式的利弊，结果决定进行连续波相位差式激光波高计的原理实验。本文将叙述这些研究成果。
用准连续60 W的二极管激光列阵侧面泵浦“之”字形Nd:YAG板条激光器，当泵浦功率为45 W，脉宽为400 μs时，得到3.5 mJ的激光输出。用KD*P电光开关调Q，得到18 ns(FWHM)、2 mJ的脉冲激光输出，用KTP晶体作腔内倍频，得到15 ns、0.85 mJ的二次谐波激光输出。在腔内无调Q元件且腔长小于5 cm时，于近阈值处得到单频绿光输出，而当泵浦功率稍大，腔内有数个纵模振荡时，观察到激光的反相态，并用数值模拟的结果对此作了解释。
利用缓冲质子源(苯甲酸中掺入一定量的苯甲酸锂)在Z切LiNbO3基底上制作了质子交换平面光波导,得到了不同掺杂摩尔分数(0.5%,1.0%和1.5%)的缓冲质子源质子交换波导的有效扩散系数及折射率分布。随着质子源中苯甲酸锂的摩尔含量逐渐增加,质子交换的有效扩散系数呈指数衰减,同时波导表面折射率增量线性递减。研究了有效折射率的稳定性特征,并与用纯苯甲酸制作的光波导进行了比较,发现利用缓冲质子源制作的LiNbO3光波导的稳定性明显优于纯苯甲酸制作的光波导。
Texture analysis is a basic issue in image processing and computer vision, and how to attain the rotation-invariant texture characterization is a key problem. This paper proposes a rotation-invariant texture analysis technique using Radon and Fourier tran
本文提出了一种多尺度补全卷积神经网络(MsiNet),用于光学相干层析(OCT)视网膜图像的分层。该网络充分利用了人眼视觉特性和视网膜层次特征。实验结果表明,与现有的视网膜分层网络相比,MsiNet能够实现更高的分层正确率,同时具有网络规模小和参数量少的特性。
研究了一种多层金属复合板激光冲击柔性微成形(LSFF)的新工艺,验证了该工艺的可行性, 发现在合适的工艺参数下,成形件没有层裂或裂纹等缺陷。研究结果显示, 在LSFF下, 镍/铜/镍金属复合板的成形深度介于铜箔和镍箔的之间,且成形深度随着激光能量和激光冲击次数的增加而增加。成形件表面发生了粗化现象, 且其粗糙度随着激光能量的增加而增加。