Loss-Reduction in Flexibly Vertical Coupled Ring Lasers Through Asymmetric Double Shallow Ridge and ICP/ICP Cascade Etching

Loss-reduction in flexibly vertical coupled ring lasers is demonstrated through asymmetric double shallow ridge in the main ring area and inductively coupled plasma (ICP)/ICP cascade etching. Compared with the previous counterpart, the reduced threshold current and enhanced output power are obtained; coupling ratio is tuned from 27% to 1.5% when threshold current is varied from 60 to 80 mA. Single-mode lasing with sidemode-suppression ratio of 27 dB and quality factor of 13120 is achieved when $I_{c}=15$ mA, $I_{d}=58$ mA, which are nearly twofolds of that in the previous one. Such strategies can be widely employed to reduce loss in other vertical coupled photonic circuits.      

基于准分子激光加工技术的内嵌光纤型微流控器件的制备

为了方便、快速、低成本地检测样品,提出一种内嵌光纤型微流控芯片的制备方法.利用248 nm的KrF准分子激光在聚甲基丙烯酸甲酯(PMMA)基片上进行微加工,构建芯片结构,并嵌入腐蚀过的直径35μm的单模光纤,从而形成内嵌光纤型芯片.探讨了准分子激光加工参数以及嵌入光纤的方法.结果表明,用准分子激光加工芯片,可控性好、简便可靠、加工过程可实现无人化.内嵌光纤实现了光纤的相互对准以及光纤对流道中央的对准,可以灵敏地获取样品的光学信号.     

激光直写技术应用于烫金箔隐形图像上的研制

用电子束逐行扫描方法刻蚀衍射光学元件的浮雕结构精度高而速度低。提出了一种采用逐点激光直写浮雕位相结构方法来产生具有隐形图像反射二元整形元件,指出用方点光刻位相结构有利于衍射效率的提高。在激光烫金箔上制作具有隐形图像功能的二元整形位相结构,再现图像的 1级衍射效率可达12％—21％,给出了实验结果。     

会聚光全反射法测量物质折射率

使用会聚光从折射率已知的光学材料中入射并聚焦到该光学材料与待测的物质的分界面上，测量反射光强度或反射率的空间分布，根据全反射原理可计算出待测物质的折射率，这是一种简便且易于用计算机控制和自动采集并处理数据的方法，适用于微小样品的各种材料（包括生物组织体）的折射率性质的研究。     

Enhancing Light Emission of Nanostructured Vertical Light‐Emitting Diodes by Minimizing Total Internal Reflection

Nanostructured vertical light‐emitting diodes (V‐LEDs) with a very dense forest of vertically aligned ZnO nanowires on the surface of N‐face n‐type GaN are reported with a dramatic improvement in light extraction efficiency (～3.0×). The structural transformation (i.e., dissociation of the surface nitrogen atoms) at the nanolevel by the UV radiation and Ozone treatments contributes significantly to the initial nucleation for the nanowires growth due to the interdiffusion of Zn into GaN, evident by the scanning photoemission microscopy (SPEM), high‐resolution transmission electron microscopy (HR‐TEM), and ultraviolet photoelectron spectroscopy (UPS) measurements. This enables the growth of densely aligned ZnO nanowires on N‐face n‐type GaN. This approach shows an extreme enhancement in light extraction efficiency (>2.8×) compared to flat V‐LEDs, in good agreement with the simulation expectations (～3.01×) obtained from 3D finite‐difference time‐domain (FDTD) tools, explained by the wave‐guiding effect. The further increase (～30%) in light extraction efficiency is also observed by optimized design of nanogeometry (i.e., MgO layer on ZnO nanorods).     

国产LD 泵浦掺Yb 双包层光纤光谱特性研究

研究了国产掺Yb双包层光纤在国产980nm半导体激光器的泵浦下，在不同条件下所产生的自发辐射谱、放大的自发辐射(ASE)谱和激光光谱。分析了ASE的特性，与超荧光作了区别，并分析了激光的模式竞争。一方面，验证了国产双包层光纤的可行性；另一方面，通过对该实验的研究，可以加深对激光形成的理解。     

Optical Fiber Cavity Ring Down Measurement of Refractive Index With a Microchannel Drilled by Femtosecond Laser

A microchannel was inscribed in the fiber of a ring cavity which was constructed using two 0.1% : 99.9% couplers and a 10-m fiber loop. Cavity ring down spectroscopy was used to measure the refractive index (RI) of gels infused into the microchannel. The ring down time discloses a nonlinear increase with respect to RI of the gel and sensitivity up to 300 mus/RI unit and an index resolution of 1.4 times10^-4 was obtained.