上海理工大学 光电信息与计算机工程学院,上海 200093
为了简化微泡腔的制备工艺,在传统
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激光双向加热方案的基础上,采用
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激光单点加热毛细管。通过精确控制加热温度和气体流速,制备出半球形的微泡腔,进而通过调节激光光斑,增加加热面积的方式制备出球形的微泡腔。使用光学显微镜和原子力显微镜(AFM)对制备的球形微泡腔进行表征,并通过COMSOL仿真验证了所制备微泡腔的性能。所制备的微泡腔表面光滑,壁厚最薄处可达到亚微米量级。研究结果表明,通过
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激光单点加热制备的微泡腔的壁厚存在轻微的不均匀性,但其谐振Q值仍然较高,可广泛应用于传感领域。
CO2激光 单点加热 球形微泡腔 谐振品质因数 CO2 laser single-spot heating spherical microbubble resonant quality factor
上海理工大学光电信息与计算机工程学院, 上海 200093
在对微纳材料光学特性表征中, 需要获得分辨率更高的波长和强度的荧光图像。普通的显微镜无法满足测试的要求, 因此将普通的成像显微镜、光谱仪以及纳米移动台组成激光扫描显微镜成像系统, 并利用 LabVIEW开发了一套完整的集二维扫描采集与信号图像处理一体的系统上位机软件。扫描采集过程使用了低通滤波等数字信号处理方法消除光谱仪信号噪声的影响。利用本系统测量硒化镉纳米带、单层二硫化钼得到了荧光强度图像以及荧光峰值波长图像, 能分辨出最小波长为 0.03 nm的荧光。将采集长度与实际长度进行比较并分析荧光强度差异, 取得了较好的效果。
激光扫描成像 光谱仪去噪 荧光峰值波长图像 荧光强度图像 Laser scanning imaging LabVIEW LabVIEW spectrometer denoising fluorescence peak wavelength image fluorescence intensity image
Author Affiliations
Abstract
Laboratory of Integrated Opto-Mechanics and Electronics, Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), University of Shanghai for Science and Technology, Shanghai 200093, China
We demonstrate an effective approach of mode suppression by simply using a tungsten probe to destroy the external neck surface of polymer microbottle resonators. The higher-order bottle modes with large axial orders, spatially located around the neck surface of the microresonator, will suffer large optical losses. Thus, excitation just with an ordinary free-space light beam will ensure direct generation of single fundamental bottle mode lasers. This method is with very low cost and convenient and can obtain high side-mode suppression factors. Our work demonstrated here may have promising applications such as in lasing and sensing devices.
140.3570 Lasers, single-mode 140.3945 Microcavities 160.5470 Polymers Chinese Optics Letters
2019, 17(12): 121401
上海理工大学光电信息与计算机工程学院, 上海 200093
为了解决微纳光纤之间的结构稳定性差的问题, 使用 CO2激光作为加热源, 加热两根重叠在一起的微纳光纤, 并在显微镜下观察其熔接情况, 最终将两根微纳光纤熔接成一根, 而且熔接点的光纤表面光滑, 直径均匀。通过 CO2激光加热的方法, 实现了微纳光纤高质量的熔接, 增加了微纳光纤之间的机械稳定性, 使其更容易制作出纳米光子器件。
微纳光纤 倏逝波耦合 激光熔接 micro-nano optical fiber evanescent wave coupling laser welding
Author Affiliations
Abstract
1 Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instrument and System (Ministry of Education), University of Shanghai for Science and Technology, Shanghai 200093, China
2 State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
Due to the lack of mode selection capability, single whispering-gallery-mode (WGM) lasing is a challenge to achieve. In bottle microresonators, the highly nondegenerated WGMs are spatially well-separated along the long-axis direction and provide mode selection according to their axial mode numbers. In this work, we use a loss-engineering approach to suppress the higher-order WGMs and demonstrate single-mode lasing emission in small polymer bottle microresonators. The fiber tapers are not only used to couple pump light into the bottle microresonators to excite the WGMs but also to bring optical losses that are induced from the diameter mismatch between fiber tapers and microresonators. By adjusting the coupling positions, the diameters of fiber tapers, and the coupling angles, single fundamental-mode lasing is efficiently generated with side-mode suppression factors over 15 dB. Our loss-engineering approach is convenient just by moving the fiber taper and may find promising applications in miniature tunable single-mode lasers and sensors.
(140.3570) Lasers single-mode (140.3945) Microcavities (160.5470) Polymers. Photonics Research
2017, 5(6): 06000B29