Phase shifter based on bacteriorhodopsin film and its application

A phase shifter based on photoinduced anisotropy of bacteriorhodopsin film was designed and applied in phase-shifting interferometry. Photoinduced anisotropy in bacteriorhodopsin film is based on photoanisotropic selective bleaching of bacteriorhodopsin molecules under polarized excitation light. It is modulated by the polarization orientation of the linearly polarized excitation light. While it passes through the anisotropic bacteriorhodopsin film, a circularly polarized light is converted into an elliptical polarized light. The polarization properties of the elliptical polarized light are dependent on the polarization orientation of the linearly polarized excitation light. A phase shifter based on the photoinduced anisotropy of bacteriorhodopsin film was presented theoretically by Jones matrix and experimentally. Phase shift is controlled by the polarization orientation of the external excitation light, thus, it can be controlled without moving parts inside the Mach-Zender interferometer, which contributes to the mechanical stability of the system. Least square method, which bases on four-step phase-shifting interferometry, was applied to the reconstruction of the profile of phase object. The experiments were conducted to verify the feasibility of this phase shifter on the phase-shifting interferometry.