Multiphoton Polarization Microscopy

Abstract

Abstract By analyzing the polarization or anisotropy using steady-state or time-resolved methods, orientation information or dynamics of molecular systems can be investigated (Lakowicz, 1999). The natural extension of polarization spectroscopy is to implement polarizationresolved analysis in conjunction with optical microscopy. In this approach, spatially specific orientation information with submicron resolution can be obtained from biological specimens. A number of experimental approaches have been implemented using polarization microscopy techniques such as confocal polarization microscopy and modulated polarization microscopy (Axelrod, 1989; Massoumian et al., 2003; Wilson & Juskaitis, 1995). With the implementation of different forms of polarization microscopy, many studies in the biological and medical sciences have also been conducted. For example, collagen imaging, corneal microscopy, and the dynamics of cytoskeleton are a few examples in which polarization-resolved microscopy has been readily applied (AsiyoVogel et al., 1997; Gitirana & Trindade, 2000; Kuhn et al., 2001). In addition, polarization microscopy has been used to measure the orientation of single chromophores and quantum dots (Chung et al., 2003; Empedocles et al., 1999). Time-resolved polarization microscopy has also been used to probe dynamic phenomena inside cells such as the cytoplasmic viscosity (Fushimi & Verkman, 1991).