Raman microscopy has very high spatial resolution. For example, the lateral and depth resolutions were 250 nm and 1.7 Ám, respectively, using a confocal Raman microspectrometer with the 632.8 nm line from a HeNe laser with a pinhole of 100 Ám diameter. Since the objective lenses of microscopes focus the laser beam to several micrometres in diameter, the resulting photon flux is much higher than achieved in conventional Raman setups. This has the added benefit of enhanced fluoescence quenching. However, the high photon flux can also cause sample degradation, and for this reason some setups require a thermally conducting substrate (which acts as a heat sink) in order to mitigate this process.
By using Raman microspectroscopy, in vivo time- and space-resolved Raman spectra of microscopic regions of samples can be measured. As a result, the fluorescence of water, media, and buffers can be removed. Raman microscopy for biological and medical specimens generally uses near IR lasers (785 nm diodes and 1064 nm Nd:YAG are especially common). This reduces the risk of damaging the specimen by applying higher energy wavelengths.