FIGURE 3.

(a) Measured photoelectric response characteristics of dried film of BR oriented between two ITO plates. The fast (B1) and slow (B2 and B3) components are associated with both structural changes in the protein as well as net translocation of the proton. The rise and decay time of B1 could not be accurately measured due to the limited bandwidth of the measurement system. The photoelectric response of the BR film as a function of scanning distance is shown in b. The pump and probe beams were focused during the mapping process to achieve a spatial resolution of 300 μm. The inset indicates that, in the electro-optic sampling measurement, the detected light intensity is directly proportional to the electric field inside the BGO crystal.