The invention belongs to the technical field of optical detection, and relates to a high-sensitivity optical detection device. The high-sensitivity optical detection device comprises an antiferromagnetic layer, a pinning layer, a
barrier layer, a free layer and a
precious metal micro-nano structure. According to the high-sensitivity
light detection device, the pinning layer, the
barrier layer and the free layer form a magnetic
tunnel junction. When the device is used, to-be-measured light irradiates the
precious metal micro-nano structure, and meanwhile, a fixed
magnetic field is applied to the device. The intensity or
wavelength of the to-be-measured light is determined by measuring the
magnetoresistance difference of the magnetic
tunnel junction under the
irradiation of the to-be-measured light and without the
irradiation of the to-be-measured light. According to the high-sensitivity
light detection device of the invention,
precious metal micro-nano structures with different sizes or shapes can be arranged, so that the resonant
wavelength of the precious
metal micro-nano structures can be adjusted, so that detection of incident light with different wavelengths is realized. Therefore, the high-sensitivity
light detection device of the invention has the
advantage of wide detection
wavelength range of light, and has a good application prospect in the field of light detection.