Polychromatic polarization microscopy: new technique for studying weak birefringent structures

           A new technique for analyzing structures at nanoscale with polarizing microscopy has been developed: polychromatic polarization microscopy (Shribak, Scientific Reports, 5:17340, 2015; doi:10.1038/srep17340). One of the limitations of exisitng polarizing microscopic techniques was that samples with small retardances (like biological soft tissue samples) required digital processing to be rendered visible in the field of view. The new technique allows the visualization of birefringent samples without digital processing and the structures appear colored regardless their orientation in relation to the diagonal position (position at which strutuctures present maximun brightness in conventional polarization microscopy). The resulted image of the new polychromatic polarization microscopy shows birefringent objects with different brightness (relative to their retardances) and colors (relative to the orientaiton of their slow axis). The new technique is independent of sample orientation and the image can be seen through the eyepieces without digital processing.
  The new technique opens the possiblity of studying biological samples with small retardances, with applications in the diagnosis of various diseases and imaging of low birefringent crystals (like in carious, fluortic and developing enamel).