FIG 1.

(a) Conventional confocal Raman microspectrometer. The laser irradiates the object selected in the optical microscope (laser spot ≈ 2 μm), the scattered light from the sample is collected by the optics of the microscope passing through holographic filters, pinhole, and monochromator to be detected by a charge-coupled device (CCD). (b) Handheld Raman spectrometer allows direct measurements on outcrops (cyanobacteria on siliciclastic rocks at Albertov, Prague, Czech Republic). The rugged probe head permits laser illumination of the object and collection of the scattered light.