Low-coherence interference microscope in transmission mode

Low-coherence interference microscope in transmission mode

Paper in proceedings (conference paper)

The system is based on the Mach-Zehnder interferometer with a diffraction grating as a beam splitter. The interferometer arms intersect gently inclined to each other so the interference structure is an image-plane hologram. The hologram is recorded using a CCD camera and processed by a computer. The phase image component may be extracted from the hologram in addition to the intensity one. The latter is depth discriminated as it is in a classical confocal microscope. This effect is a consequence of the spatial incoherence of illumination (correlation effect) that, in the reflection-mode microscope, could be with benefit combined with the temporal one. The advantage of this technique is that the optical section is formed at a time without any need of scanning. The setup is build to be achromatic - the interference structure in the output plane of the interferometer is achromatic within the entire field of view. Hence a white-light (broad) source may be used which solves the problems with coherent light - image degradation by speckles or by unintended interference. Optical path difference measurement enhanced by the optical sectioning is demonstrated experimentally in the paper.

The system is based on the Mach-Zehnder interferometer with a diffraction grating as a beam splitter. The interferometer arms intersect gently inclined to each other so the interference structure is an image-plane hologram. The hologram is recorded using a CCD camera and processed by a computer. The phase image component may be extracted from the hologram in addition to the intensity one. The latter is depth discriminated as it is in a classical confocal microscope. This effect is a consequence of the spatial incoherence of illumination (correlation effect) that, in the reflection-mode microscope, could be with benefit combined with the temporal one. The advantage of this technique is that the optical section is formed at a time without any need of scanning. The setup is build to be achromatic - the interference structure in the output plane of the interferometer is achromatic within the entire field of view. Hence a white-light (broad) source may be used which solves the problems with coherent light - image degradation by speckles or by unintended interference. Optical path difference measurement enhanced by the optical sectioning is demonstrated experimentally in the paper.

low-coherence interferometer; interference microscopy; holographic microscopy; confocal microscopy; optical sectioning; spatial coherence; correlation effects

low-coherence interferometer; interference microscopy; holographic microscopy; confocal microscopy; optical sectioning; spatial coherence; correlation effects

KOLMAN, P.; CHMELÍK, R.; LOVICAR, L.; SUCHOMEL, F.

01.03.2005

Jena, Germany

Focus on Microscopy 2005 - Jena, Germany. March 20-23, 2005. Appendix to the abstract book.

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