Holographic Multipoint Raman Microscopy

We present a multipoint Raman microscope using a computer generated hologram (CGH) in combination with a confocal pinhole array in the intermediate plane to filter out the unwanted information from unfocused layers. Due to the weak Raman signal it is in general unavoidable to use long integration times for the sensor to detect the spectrum. We show an optical setup which is suitable to record multiple spectra in a single shot and, therefore, has the potential to shorten the integration time. In addition, it is possible to measure the Raman spectrum of local different points and, thus, cover an extended specimen where otherwise multiple scanning measurements would be needed. We describe the optical setup and the difficulties which make it mandatory to place a confocal pinhole in the optical path. As a technical sample we show multipoint measurements of silicon and as an example for a biological application we measure the Raman signal of a pig’s kidney.