The J-1500 and J-1700 CD spectrometers use circularly polarized light that is generated by phase modulation. By controlling the amplitude of the phase modulation, it is also possible to measure linear dichroism (LD), which is the differential absorption of light polarized parallel and perpendicular to an orientation direction. Using this same principle, when polarized light interacts with a fluorescent molecule, the resulting fluorescence emission has different intensities along different polarization axes. This fluorescence anisotropy can be measured as shown in the diagram below where the polarized light passes first through a polarizer (analyzer) and then a detector that is positioned at 90° relative to the excitation beam. The polarizer is oriented so that only the vertical component of light passes to the detector.
Accessories for Fluorescence polarization anisotropy
PTC-PLH Polarizer for PTC-510/517
Adding this polarizer to the emission optics and utilizing the alternating horizontal and vertical polarization allows for the measurement of fluorescence polarization and anisotropy.
FDCD-PLH Polarizer for FDCD-550
This polarizer can be used with the FDCD-550 system to add fluorescence polarization and anisotropy capability in addition to FDCD.