We proposed a method to measure the electro-optical effects of a blue phase liquid crystals (BPLCs) using a two-beam interference microscope combining a Mach-Zehnder interferometer with a polarized reflection microscope. The two-beam interference microscope enable us to simultaneously measure phase modulation and the change of Bragg reflection wavelength attributed to the local reorientation of LC molecules and electrostriction of BPLCs, respectively. We investigated the field intensity depen-dency, temperature dependency, and time response of the phase modulation and reflection spectra.
