Aiming for suppressing side-mode and spectrum broadening, a slit beam-shaping method and super-Gaussian apodization processing for femtosecond laser point-by-point (PbP) inscription technology of fiber Bragg gratings (FBGs) are reported here. High-quality FBGs, featuring narrow bandwidth of less than 0.3 nm, high reflectivity above 85%, low insertion loss (0.21 dB), and low cladding loss (0.82 dB), were obtained successfully. By a semi-automatic PbP inscription process, an array consisting of six FBGs, exhibiting almost no side-mode peaks with high suppression ability and narrow bandwidth, was fabricated along three independently developed single-mode fibers with an interval of 20 mm.

针对传统计算全息法生成的贝塞尔光束阵列均匀性差，能量利用率低的问题，提出了两种计算全息法，分别可以生成高质量的平行、发散贝塞尔光束阵列。提出多轴锥透镜相位并行拼接法，通过提高窗口的“口径利用率”，有效降低了光场的背景噪声，提高了能量利用率，仿真结果表明，所产生的3×3平行贝塞尔光束阵列均匀性为98.94%，衍射效率为78.12%；提出多透镜和轴锥透镜相位叠加法，通过多个透镜和轴锥透镜相位叠加来调控贝塞尔光束的数量和位置，透镜相位对贝塞尔光束起到聚焦的作用，可以在透镜后焦面附近得到中心光斑直径缩小的贝塞尔光束阵列，仿真结果表明，所产生的3×3发散贝塞尔光束阵列均匀性为97.95%，衍射效率为79.23%。实验采集了贝塞尔光束阵列沿传输方向120 mm，130 mm，140 mm位置处的图像，与仿真结果高度一致。相比于传统方法，本文所提方法产生的平行、发散贝塞尔光束阵列均匀性分别提高了2.97%和4.70%，衍射效率分别提高了48.22%和54.75%。

采用钛蓝宝石飞秒激光加工系统在融石英表面诱导表面周期性微纳结构，研究了激光诱导表面周期结构的形成过程以及激光能量密度、脉冲数、光斑大小和脉冲的空间间隔对融石英表面激光诱导表面周期结构的形貌的影响。实验结果表明，飞秒激光在融石英表面可以诱导出周期性的亚波长结构，主要以垂直于激光偏振方向的光栅状结构为主，其周期在百纳米量级且具有更好的可复现性。在激光光斑控制在1 μm附近时，所得到的形貌具有较高的规则性。根据实验结果设计了聚焦高斯光斑低通量的加工方式。所制备的光栅结构具有200~300 nm的周期，平均深度约为300 nm。

以多元金属纳米薄膜（金、银）为基底，利用飞秒激光加工技术制备得到多元等离子体纳米结构，并研究了其局域表面等离子体共振效应（ Local Surface Plasmon Resonance，LSPR）和表面增强拉曼散射（Surface Enhanced Raman Scattering，SERS）性能。利用时域有限差分（Finite Difference Time Domain，FDTD）软件模拟了不同情况下（单层金膜、金银双层金属薄膜的平面以及阵列结构）的电场分布情况。根据仿真结果，相较于平面金属膜来说，飞秒激光制备的微纳结构阵列附近区域产生电磁场增强，集中在结构边缘处，且其强度变化与预期结果基本保持一致。此外，使用浓度为10⁻⁴ M和10⁻⁶ M的罗丹明（R6G）溶液进行SERS性能测试。测试的结果表明，单层平面金膜基本没有SERS峰值信号出现，而单层金膜上制备的等离子体纳米结构附近出现峰值信号，双层金属薄膜上制备的等离子体纳米结构展现出更高的SERS峰值信号。多元金属等离子体纳米结构展示出更强的局域表面等离子体共振效应，从而在表面增强拉曼散射、光催化、生物传感等领域具有广泛的应用。

Surface-enhanced Raman scattering (SERS), owing to its high sensitivity based on localized surface plasmon resonance of nanostructured metals, is recently attracting much attention to be used for biotechnology, such as cell imaging and tumor therapy. On the other hand, the trace detection of bio-molecules with large molecular weight is still challenging because the troublesome treatment of SERS substrate using coupling or cross-linking agents is required. In this paper, we apply liquid interface assisted SERS (LI-SERS) method, which provides unique features of collection and self-immobilization of analyte molecules on the SERS substrate, to realize the label-free trace detection of bio-molecules with detection limits of pM ~ fM. Specifically, deoxyribonucleic acid (DNA) discrimination and quantitative detection of β-Amyloid (Aβ) in trace-concentration are demonstrated to illustrate the ultrahigh sensitivity and versatility of the LI-SERS method. The results suggest LI-SERS is promising for the early-stage diagnosis of diseases such as virus infection and Alzheimer's disease.Surface-enhanced Raman scattering (SERS), owing to its high sensitivity based on localized surface plasmon resonance of nanostructured metals, is recently attracting much attention to be used for biotechnology, such as cell imaging and tumor therapy. On the other hand, the trace detection of bio-molecules with large molecular weight is still challenging because the troublesome treatment of SERS substrate using coupling or cross-linking agents is required. In this paper, we apply liquid interface assisted SERS (LI-SERS) method, which provides unique features of collection and self-immobilization of analyte molecules on the SERS substrate, to realize the label-free trace detection of bio-molecules with detection limits of pM ~ fM. Specifically, deoxyribonucleic acid (DNA) discrimination and quantitative detection of β-Amyloid (Aβ) in trace-concentration are demonstrated to illustrate the ultrahigh sensitivity and versatility of the LI-SERS method. The results suggest LI-SERS is promising for the early-stage diagnosis of diseases such as virus infection and Alzheimer's disease.