Oldenbourg Rudolf

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Last Name
Oldenbourg
First Name
Rudolf
ORCID
0000-0003-1055-8692

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Subject: Birefringence ×

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Now showing 1 - 3 of 3
  • Preprint
    Mapping birefringence in three dimensions using polarized light field microscopy : the case of the juvenile clamshell
    ( 2018-05) Tran, Mai Thi ; Oldenbourg, Rudolf
    We report methods to generate three dimensional maps of birefringence, its position and orientation in juvenile shells of the Atlantic hard clamshell (Mercenaria mercenaria). For measuring the retardance and optic axis orientation of curved shell surfaces in three dimensions, we developed enhanced acquisition and processing algorithms and combined results from conventional and light field imaging approaches to reconstruct the three dimensional shell shape and its anisotropic optical properties. Our work represents the first successful attempt to generate such maps at a spatial resolution of about 2 m and angular steps of about 9° in terms of the inclination angles of the optic axis. The maps of clamshell birefringence provide structural insights into the early mineralization during juvenile clamshell development.
  • Preprint
    Polarized light microscopy in reproductive and developmental biology
    ( 2013-05) Koike-Tani, Maki ; Tani, Tomomi ; Mehta, Shalin B. ; Verma, Amitabh ; Oldenbourg, Rudolf
    The polarized light microscope reveals orientational order in native molecular structures inside living cells, tissues, and whole organisms. Therefore, it is a powerful tool to monitor and analyze the early developmental stages of organisms that lend themselves to microscopic observations. In this article we briefly discuss the components specific to a traditional polarizing microscope and some historically important observations on chromosome packing in sperm head, first zygote division of the sea urchin, and differentiation initiated by the first uneven cell division in the sand dollar. We then introduce the LC-PolScope and describe its use for measuring birefringence and polarized fluorescence in living cells and tissues. Applications range from the enucleation of mouse oocytes to analyzing the polarized fluorescence of the water strider acrosome. We end by reporting first results on the birefringence of the developing chick brain, which we analyzed between developmental stages of days 12 through 20.
  • Preprint
    Polarized light imaging of birefringence and diattenuation at high resolution and high sensitivity
    ( 2013-07) Mehta, Shalin B. ; Shribak, Michael ; Oldenbourg, Rudolf
    Polarized light microscopy provides unique opportunities for analyzing the molecular order in manmade and natural materials, including biological structures inside living cells, tissues, and whole organisms. 20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging and digital image processing for fast and comprehensive image acquisition and analysis. The LCPolScope is commonly used for birefringence imaging, analyzing the spatial and temporal variations of the differential phase delay in ordered and transparent materials. Here we describe an alternative use of the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship between the quantities measured with either instrument, and touch on the physical connection between refractive index, birefringence, transmittance, diattenuation, and dichroism.