Apodized Phase Contrast Microscopy Applying to Biomedical Science

Abstract

Apodized phase contrast microscopy is a microscopic technique which visualizes fine structure of, such as intact biological cells, colourless and transparent phase objects. It uses the apodized phase plate placed at the Fourier transfer plane conjugating to the illuminating aperture. The apodized phase plate has a quarter wave phase shift ring with absorption and two adjacent apodization areas with absorptions. It weakens selected diffracted light through phase objects. Although conventional phase contrast method produces the halo artifact, a phenomenon in the image of large phase objects, the apodized phase contrast method reduces these halos and provides inner detailed images. We have recently developed apodized phase contrast objectives for bright high contrast (ABH), with a 2%-transmittance phase ring and adjacent 8%-transmittance apodization areas. These provide high sensitivities and to detect wider range of phase differences. We applied these ABH objectives to biomedical applications such as identification of asbestos, motion of cellular organelles and early embryos. This paper also describes a pupil-projection apodized phase contrast microscopy with an inverted microscope. This microscopy works with high-NA bright field objective lenses.