The paper studies the high-sensitive detection of light radiation pressure using an adaptive interferometer based on photorefractive 45○-cut BaTiO3 : Co crystal. For small phase modulation measurement the authors employed a polarization filtering, which ensured the linear regime of signal detection in the photorefractive crystal with nonlocal response. It was demonstrated that the proposed method of light pressure measurement could be used as a broadband photodetector. It was experimentally found that the sensitivity was 2 µW in the wavelength range from 488 to 1600 nm.