移频激发差分拉曼光谱仪的多波长光源设计

Design of Multi wavelength Light Source for Shifted Excitation Raman Difference Spectroscopy

摘要:

拉曼光谱检测常常受到荧光的干扰，影响了该技术的推广应用。移频激发差分拉曼光谱方法（SERDS方法）已被证明是一种有效的荧光抑制方法。SERDS实现荧光抑制的关键在于其特殊的激光光源，不仅要求其输出多个相近的波长，而且要求输出的激光功率较高、光谱线宽窄。采用Littrow光栅外腔半导体激光器原理设计实现了一种低成本、便携式的激光光源，可以在15nm的调谐范围内输出多个波长，光谱线宽小于0.2nm，输出功率可达80mW，适合用作移频激发差分拉曼光谱方法的多波长光源，实现拉曼光谱检测中对荧光干扰的抑制。

Abstract:

The application of Raman spectroscopy is often limited by fluorescence disturbances. Shifted excitation Raman difference spectroscopy (SERDS) has been proven to be an effective method for fluorescence rejection. The key of SERDS based fluorescence suppression lies on its special laser source. It is required not only to generate several close spaced wavelengths, but also to get high power and narrow spectral line width. In this paper, a low cost, portable external cavity diode laser based on Littrow structure is proposed and implemented. A wavelength tuning range of 15nm can be achieved with spectral line width less than 0.2nm, and the output laser power is up to 80mW. Such features make it suitable for SERDS light source to realize fluorescence suppression in Raman spectroscopy.