Device for quantitatively detecting carbon 14 isotope by dual-wavelength method, and spectrograph

The invention provides a device for quantitatively detecting the C14 isotope by the dual-wavelength method,and a spectrograph. Two paths of mid-infrared laser beams with different wavelengths are locked on the optical cavity of one sample chamber to ensure that the two paths of light are collinear, and the cavity length of the optical cavity is adjusted by the cavity length adjusting unit to tune the mode frequency of the optical cavity, the frequencies of the two paths of mid-infrared laser beams are tuned to enable the frequencies of the two paths of mid-infrared laser beams to be matched with different energy levels of the target isotope molecules at the same time; after the intermediate infrared laser frequency and the energy level of the target isotope molecule are matched at the same time, the target isotope molecule is excited by the two paths of intermediate infrared laser beams at the same time, and an optical cavity output signal of the second intermediate infrared laser passing through the optical