This study introduces a high-speed water-cooled rotary laser with an innovative cooling mechanism. Thermal analysis confirms the system’s exceptional heat dissipation capabilities. Compared to traditional rotary disk lasers, this laser fully utilizes high thermal conductivity efficiency of water cooling and low absorption coefficient of the gain medium to reduce thermal stress. We introduce a novel "quasi-rotation" mechanism for the water-cooled rotary laser to resolve the issue of water pipe entanglement. To achieve this, we propose an eccentric rotation design that utilizes a single motor to deliver uniform, high-speed rotation with exceptional stability. Initial experiments demonstrate a maximum output power of 76.5 W, a slope efficiency of 58.2%, and a power conversion efficiency of 52.4%. Output power is primarily limited by the available pump power in our lab. We also analyze the impact of water temperature and rotation speed on output power. Both continuous and pulsed pumping experiments further validate the system’s robust thermal management. Overall, our results highlight the significant potential of "quasi-rotating" water-cooled laser technology to enhance the power output of solid-state lasers.

The transformation of a Gaussian beam by a thin lens is an important component of the laser principles course, as it enhances students' understanding of laser optical system design. However, because the course usually omits the general propagation of arbitrary laser beams through linear optical systems, students often raise questions when they try to extend their knowledge. This paper derives, under the second-order moment definition, the waist diameter, waist position, and far-field divergence angle of a general laser beam after passing through a linear optical system represented by a ray-transfer matrix. In addition, we retrace the beam-parameter transformation with the q-parameter method, demonstrating the consistency of the two approaches and thereby reinforcing students' understanding of laser-beam behavior. The general beam-parameter transformation theory can be expected to find direct application in the design of multi-lens beam-transformation systems.

To address thermal effects in end-pumped solid-state lasers, this paper introduces a new motion concept called “quasi-rotating” and proposes a specialized method for evaluating the thermal focal length of dynamic gain medium, which proves valuable for resonator design. Using the finite element numerical analysis method, we analyze the changes of the temperature field distribution within the crystal and demonstrate the effectiveness of the “quasi-rotating” cooling system in thermal management. The results show that the “quasi-rotating” frequency and pump power have a more significant influence on the thermal lens effect than the cooling water temperature. Compared to previous studies, our new method accurately predicts the thermal focal length of the moving crystal and provides direct guidance for resonator design, as shown in this paper. These findings provide a theoretical foundation for the design and enhancement of high-power solid-state lasers. Moreover, the approach offers meaningful insights for the design of other non-traditional lasers with dynamic gain medium.

黑体辐射和受激辐射等概念对于光电专业的学生是非常基础的概念,通过统计物理课程光子气体章节的讲授,系统地引入这些概念对于光电专业的学生系统掌握专业知识非常重要.笔者介绍了通过实践总结的讲授过程,对其中一些细节的把握进行了详细分析.

High-quality pentacene-doped p-terphenyl bulk crystals were grown by the selective self-seeding vertical Bridgman technique (SSVBT). The lattice structure and crystal properties of the samples of different doping concentrations and their relations with p-terphenyl single crystals were tested and analyzed. The doping effects of pentacene doping at different concentrations in p-terphenyl molecular crystals are discussed. The powder X-ray diffraction, FTIR, and 1H NMR studies show that no additional peaks (except for p-terphenyl) are observed in the spectra of two doped crystals. The results indicate that guest molecules appear as defects in the form of irregularly oriented molecules which do not significantly change the crystal structures. As the doping concentration increases, the average crystallite size decreases, and the crystallinity declines. The ultraviolet–visible absorption and fluorescence spectra show that with added pentacene molecules, the characteristic peak intensities decrease in the spectra owing to the p-terphenyl molecular transition. Meanwhile, characteristic peaks appear due to the pentacene molecular transition. Moreover, with the increase of doping concentration, the intensities of characteristic peaks of host molecules decrease continuously, and those of guest molecules increase accordingly.

拉比强信号理论是激光与原子相互作用中一个非常重要的理论.在教学过程中,通过学生所提出的问题,本文从其结论进行分析,发现拉比强信号理论的结果与原子初始条件有很大的关联.通过这种分析进一步理解了量子力学的结果中相位往往起着很大的作用.

本文结合光电信息科学与工程专业的特点,以"光线"和"高斯光束"的推导为例,探索关于自由空间中光传输理论模型的内在联系的教学,实践证明这种方法对于学生理解关于光传输的后续课程非常必要,为工科专业基础理论课的课程教学提供一定参考.

为了对小尺寸抛物面反射镜进行质量检测,采用平行光聚焦的方法测量焦距,旋转被测反射镜的方法测量偏心角,再结合图像处理的方法测量弥散斑大小,并提出了一种减小测量误差的方法;对这些测量方法进行了理论分析和实验验证,得到了待测反射镜的焦距、偏心角和弥散斑大小.结果表明,焦距的相对误差在0.1％以内,偏心角误差在7％以内,弥散斑大小小于0.2mm,测量结果可靠.该方案设计为其它小口径的非球面的检测提供了很好的思路,并且为减小测量误差、提高测量精度提供了很好的研究方法.

为了探究涡旋空心光束在端面抽运Nd:YVO4微片激光器中的生成条件及其变化因素,构建了一种基于轴棱锥-透镜组生成环形抽运光的新方法.采用ZEMAX对抽运光进行了仿真分析,并基于热效应分析进行了模式匹配计算,通过实验成功得到了环形抽运光和环形空心激光输出,并通过实验验证了输出光为1阶涡旋光.结果表明,该方法能够生成光束大小可控的808nm抽运光,其光斑半径可随轴棱锥锥顶与透镜焦平面的相对位置快速变化;并且该抽运光能够使谐振腔长度为300μm的微片激光器输出稳定的1064nm 1阶拉盖尔-高斯涡旋空心光束.此研究结果对于微片激光器输出涡旋空心光束的实际方法的建立具有重要的指导意义.

针对多路数控机床运行过程中难以实现实时监测和自动报警问题,提出一种基于STM32和云平台的同步监测方法,并对状态监测系统的硬件系统和软件流程进行设计.利用NB-IoT网络和MQTT即时通信协议连接云平台,使用SIM800C通信模块提供网络连接,实现数控机床状态监测数据和云平台的稳定连接和监测.该系统具有成本低、可二次开发、易维护等特点,可满足多线路监测、实时报警的工业物联网需求.

为了测量金属和绝缘表面两种材料的粗糙度参量,采用了基于激光散射法的斜入射粗糙度测量系统.用半导体激光器作光源,用互补金属氧化物半导体工业相机拍摄粗糙度表面的散射光斑,分析光斑特征参量与粗糙度之间的对应关系,通过理论分析和实验验证了特征参量与粗糙度值之间存在单调性关系,利用MATLAB设计图形用户界面,实现粗糙度值的一键式测量功能.结果表明,该系统的系统结构简单,对金属样品和塑料绝缘表面进行测试,测量结果与触针式测量之间的误差小于8％(其中绝缘表面小于5％),能够实现不同材料表面的粗糙度值测量.这一结果对物体表面的粗糙度测量研究是有帮助的.

It is well-known that electric spin angular momentum and electric orbital angular momentum are conserved under paraxial propagation of travelling waves in free-space. Here we study the electric and magnetic angular momentum in counter-propagating waves and show both theoretically and experimentally that neither component alone is conserved except in special cases. We attribute this non-conservation to spin-spin and orbit-orbit coupling between the electric and magnetic fields. This work generalises previous findings based on travelling waves, explains the apparent spin-orbit coupling in counter-propagating paraxial light, and broadens our understanding of angular momentum conservation in arbitrary structured light waves.

It is well-known that electric spin angular momentum and electric orbital angular momentum are conserved under paraxial propagation of travelling waves in free-space. Here we study the electric and magnetic angular momentum in counter-propagating waves and show both theoretically and experimentally that neither component alone is conserved except in special cases. We attribute this non-conservation to spin-spin and orbit-orbit coupling between the electric and magnetic fields. This work generalises previous findings based on travelling waves, explains the apparent spin-orbit coupling in counter-propagating paraxial light, and broadens our understanding of angular momentum conservation in arbitrary structured light waves.

We propose a new method to generate optical needles by focusing vector beams comprised of radially polarized component and azimuthally polarized vortex components. The radial part can generate longitudinal polarization, while the azimuthal parts can generate left- and right-handed polarization. Hence, an arbitrary 3D polarization can be obtained. To our knowledge, it may be the first time that arbitrarily polarized optical needles whose transverse sizes are under 0.5 λ have been achieved. The polarized homogeneity of the needles is beyond 0.97.

为了产生径向偏振光,采用组合半波片和组合线偏振片在腔外对线偏振光做极化整形的方法,进行了理论分析和实验验证.为检测该径向偏振光产生系统的性能,采用旋转检偏器法对输出光束的偏振分布进行了检测,并用经典斯托克斯参量测量法计算了偏振纯度,最后基于马赫-曾德尔干涉的原理,检测了径向偏振光对称区域的线偏振相位关系.结果表明,当组合线偏振片为4个分块时,获得了偏振纯度为80.5％的径向偏振光,并检测出光斑对称区域的线偏振相位差为π.这一结果对在低成本条件下产生高纯度的径向偏振光是有帮助的.

The generation of homogeneously 3D spin-orientated optical needles and optical chains is investigated by focusing the annular collimated beam composed of radially polarized component and azimuthally polarized vortex components with aplanatic focusing systems. Using the Richards-Wolf vector diffraction theory, analytic expressions of focal electric fields and target spin-orientation are given. The results show that the spin-orientation is tunable by changing two parameters of the incident beam while keeping the mean size of the focal spot under 0.5λ. Spin-orientation homogeneity purity is introduced to evaluate spin-orientation homogeneity quantitatively and the results present that spin-orientation homogeneity purity is always beyond 0.996 when spin-orientation varies.

Optical needles with controllable homogeneously 3D spin-orientation generated by an annular spherical mirror is theoretically investigated in this paper. An optical needle is a 2D super-resolved electric field which has a long longitudinal size and a sub-wavelength lateral size. Such optical fields have extensive applications in many fields such as optical data storage, optical trapping and fluorescent and so on. Controllable homogeneously 3D spin- orientation provides extra degree of freedom for the optical needles, which may further extend the applications. Spherical mirrors have large aberrations, which can be used to produce super-long optical needles. It is difficult for an aplanatic focusing system to generate an optical needle which is longer than 100λ (λ is wavelength). But a spherical mirror in this paper can produce an optical needle whose LFWHM (Longitudinal full width at half maximum) is about 1000λ while keeping mean TFWHM (transverse full width at half maximum) under 0.4λ. The spin-orientation of the optical needle can be controlled by changing incident beam. By adjusting the weight factors of the radially polarized component and azimuthally polarized components, the spin-orientation in the focal region can be changed. Using the extended Richards-Wolf vector diffraction theory, the electric field can be obtained. Further, SAM (spin angular momentum) density and SOHP (spin-orientation homogeneity purity) can be calculated. The results display that the SOHP can be beyond 0.93 as long as the weight factor of the radially polarized component is not too large.

为了优化高功率板条激光器的光束质量,采用提高单侧基模光束的尺寸来限制腔内部分高阶模式振荡的方法,针对半导体侧面抽运板条激光器,测量了激光器在抽运状态下水平和竖直方向热焦距,建立了热透镜等效模型,并以平-平腔为参考,设计了水平和竖直方向单侧基模尺寸均会扩大的平-凹腔.验证了对于激光介质截面尺寸固定的板条激光器,扩大单侧基模尺寸可以限制高阶模式从而优化光束质量,并提出了进一步优化板条激光器性能的研究方法.结果表明,当平-凹腔的腔长为370mm时,输出功率为59.9W,水平方向M2因子由平-平腔的115.6显著优化至32.9,竖直方向M2因子由116.4显著优化为60.9.该研究对于板条激光器获得高质量输出及相关应用有实际意义.

We demonstrate here femtosecond pulses output from a rotary Nd:glass disk laser, mode-locked with semiconductor saturable absorber mirrors. We obtained an average output power of 0.66 W in cw operation and an average output power of 0.49 W with a duration of 324 fs in mode-locked operation in the case of an absorbed pump power of 7.3 W. To the best of our knowledge, it is the first time that sub-picosecond pulses have been obtained from rotary Nd:glass disk lasers. It shows a new concept for all-solid-state mode-locked glass lasers with high power.