Spectral measurement system built by a lock-in amplifier and a chopper, only measures the light intensity with a modulated frequency, so as to avoid the influence of other external noise, which can achieve the detection of low light with high precision.
Diagram of spectral measurement (F: SSI OE3001optical chopper G: grating spectrometer B: photoelectric probe
D: praseodymium rubidium glass samples C: sample box E: bromine tungsten light source H: computer)
The light from the bromine tungsten lamp modulated by optical chopper OE3001 becomes a light with certain frequency information. Then it becomes monochromatic light after passing through the grating spectrometer. Depending on the structure of the sample, it will absorbs the light of a particular wavelength when the monochromatic light hits the sample. Then the light converts to an electric siganl when shines on probe B. At last, the lock-in amplifier will detect this weak electric signal.