Scanning blank spectrum of the microspectrophotometer measured in the UV region (a) and visible region (b). The optimal diffraction grating for each wavelength region is installed in this monochromator. (c) and (d) Linearity between the detector signal and the intensity of incident light. The measurement wavelengths were 300 nm (c) and 440 nm (d). Closed circles show the observed values, and open circles show the theoretical values, which were obtained after subtracting the dark current.