Raman Microspectroscopy: Improvement in Signal Generation and Collection to Facilitate Raman Spectroscopy

Raman microspectroscopy offers several advantages over a traditional Raman spectroscopy setup. The major one is its superior signal collection ability owing to the use of high numerical aperture objective lens. The choice of optimal pinholes and high-quality filters also allows one to eliminate unwanted background signals to the least. Such a setup enables one to use a high-power continuous-wave (CW) laser with GHz bandwidth, not MHz, to acquire high-quality Raman spectrum at room temperature. The acquisition of Raman spectrum can therefore be performed with much less acquisition time at a proper home-built Raman microspectroscopy setup. This opens up various applications of Raman spectroscopy toward in situ spectroscopy measurement to identify crystal polymorphs, time-resolved Raman spectroscopy to follow the phase transition of materials, the detection of inorganic nanocrystals in plastic products, etc. Herein, we describe the key practical points to consider in designing and building a setup, and then introduce several applications that have been recently published from our group.