AN OPTICAL SPECTROMETER FOR A CONFOCAL SCANNING LASER MICROSCOPE

An optical spectrometer for the visible range has been developed for t he confocal scanning laser microscope (CSLM) Phoibos 1000. The spectro meter records information from a single point or a user-defined region within the microscope specimen. A prism disperses the spectral compon ents of the recorded light over a linear CCD photodiode array with 256 elements. A regulated cooling unit cools the diode array, thereby red ucing the detector dark current to a level, which allows integration t imes of up to 60 s. The spectral resolving power, lambda/Delta lambda, ranges from 400 at lambda = 375 nm to 100 at lambda = 700 nm. Since t he entrance aperture of the spectrometer has the same diameter as the detector aperture of the CSLM, the three-dimensional spatial resolutio n for spectrometer readings is equivalent to that of conventional conf ocal scanning, that is, down to 0.2 mu m lateral and 0.8 mu m axial re solution with an N.A.=1.3 objective.