Raman microscopy combines optical microscopy with the ability to determine the chemical makeup of surfaces. Laser light is delivered to the sample surface via the same objective as the optical light so a visual and chemical map can be made. The schematic in the instrument features below demonstrates the use of the laser light to excite the sample, from which Raman shifted light is collected via the wavelength selective diffraction grating and holographic filtering to remove Rayleigh scattered light.