不同的生物样本和切片,在进行拉曼探测时,会因为聚焦位置的差异及系统自身的原因导致同一光谱多次检测得到的信号强度不同,难以作定量分析。因此,需要找到一种可行性强的内标或外标的方法,从而有利于比较分析不同强度的拉曼带,实现定量检测。本文以犬类髋关节软骨切片为例,在偏振与非偏振情况下,研究标准正态变换(SNV)及多元散射校正(MSC)等常用方法对拉曼光谱的处理效果,并探究伊红染色剂(Eosin)作为一种新的内标的实际使用效果。结果发现:在非偏振条件下,MSC处理效果更理想；在偏振条件下,以伊红的特征峰1501 cm-1作为拉曼内标效果更理想。本研究证明了伊红的拉曼光谱不具有各向异性,有利于实现生物组织偏振拉曼光谱测量的归一化,且操作简单,结果更可靠。本文的结果为生物样本的拉曼光谱定量分析提供了一种可行的新方法。

在生物医学领域,拉曼光谱学越来越多地应用于目标样本或组织的在体原位无损探测。拉曼探头作为重要的拉曼检测部件,正朝着多样化和功能化方向发展。拉曼信号本身极其微弱,且易被其他噪声信号干扰,因此拉曼探头的设计生产要求极高。对现有拉曼探头的设计及构造进行了深入介绍,包括光纤选择、探头顶端设计、过滤膜/片添加和探头后端优化等;综述了拉曼探头技术在生物医学领域的拓展和应用。其中,拉曼与其他光谱或成像模式结合的探头应用,给生物医学及临床探测等领域带来了新的活力和广阔的应用前景。

Efficient continuous-wave (CW) intracavity frequency doubling of a diode-end-pumped Nd:GdVO4 laser operating on 4F_(3/2)-4I_(9/2) transitions at 912 nm has been demonstrated. A symmetrical cavity with two laser rods is designed, which divides the pump power between the two laser rods, allowing for greater power scalability. An 18-mm-long BiBO crystal, cut for critical type I phase matching, is used for the intracavity frequency-doubled laser. A maximum output power of 6.2 W in the blue spectral range at 456 nm has been achieved with the pump power of 36 W. The beam quality M2 value is 2.5 in both horizontal and vertical directions. The ellipticity of the deep blue laser is 0.98, and the power stability is better than 3.2% at the maximum output power.

A new resonator design for doubly resonant continuous-wave (CW) intracavity sum-frequency mixing (SFM) is reported. 1.12 W of coherent radiation at 588 nm is generated by mixing 1062-nm Nd:GdVO4 laser and 1319-nm Nd:YAG laser. The optical-to-optical conversion efficiency is up to 3.7%.