Ramsey spectrometer, optical lattice clock, and Ramsey spectroscopic method

A Ramsey spectrometer comprising:

• an optical path;
• an optical path length stabilization circuit configured to stabilize a length of the optical path;
• a modulator optically connected to the optical path, the modulator being configured to generate resonant laser light of a first frequency f1 that causes a resonance of an atom, a molecule, or an ion as a spectroscopic target in pulses a plurality of times and to generate non-resonant laser light of a second frequency f2 that does not cause the resonance at times between the pulses of the resonant laser light to separate the pulses of the resonant laser light;
• and
• a spectroscopic unit configured to spectroscope the spectroscopic target,
• wherein the spectroscopic unit is configured to detect a state change of the spectroscopic target corresponding to the first frequency f1, the state change being caused by irradiating the spectroscopic target with the resonant laser light.