Phase Imaging in Plant Cells and Tissues - Biomedical Optical Phase Microscopy and Nanoscopy - page 62

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Figure 4.11
Image acquired by SLIM from the outer onion epidermis. Source: Courtesy of Mustafa Mir and
Gabriel Popescu, Quantitative Light Imaging Laboratory, University of Illinois at Urbana-Champaign.
annulus condenser of the microscope. The phase ring that is fitted on the objective of the
conventional phase contrast microscope works as a phase-shifter and attenuator. The post-
processing procedure can be performed by the SLIM module on the image of the specimen,
which is redirected from the microscope to the image plane via a tube lens. The Fourier
lens L1 serves as a relay between the back focal plane of the objective and the surface of
the liquid crystal phase modulator (LCPM). The phase delay can be precisely modulated
between the scattered and the unscattered components to visualize the variation of masks on
the LCPM. Consequently, the image of the specimen will be captured by the CCD produced
by the Fourier lens L2 in the SLIM module.
Unlike, in the DIC microscopy of Nomarski double beam microscopy with complete
separation of the two partially coherent beams was in vogue from many commercial
sources. Polskie Zakłady Optyczne (PZO) had the Pluta Interference microscope, Leitz had
a double microscope for this purpose, Zeiss from West Germany had a Jamin Lebedeff
interference microscope, and Zeiss Jena had the Interphako. None of these are any longer in
production. Recently, Popescu from Illinois University has developed a commercial
microscope called SLIM. Figure 4.11 shows the outer epidermis of an onion scale.
Image of a cell layer from white onion skin was acquired using SLIM. The image covers
an area of 1939 3 1453 µ m 2 created by stitching 5 3 5 images together. At each of the
25 locations, a total of 34 z-sections were acquired spaced 4.5 µ m apart and the maximum
value from each slice was projected to create the image shown. The inset shows a