High resolution molecular spectroscopy assisted by an optical frequency comb

High resolution spectroscopy is a powerful tool for studies on detailed structure and dynamics of molecules. To observe minute effects appeared in the molecular spectra, we developed a system for high resolution spectroscopy, which was composed of an optical frequency comb and a single mode dye laser. The features of this system are high resolution, wide wavelength range, high optical power, and easy operation, so that the system makes a significant contribution to molecular spectroscopy. To demonstrate the ability of our system, we measured hyperfine spectra of fifteen B - X rovibronic transitions of molecular iodine distributed in the wide wavelength range of 570-612 nm. The absolute frequencies of hyperfine components for each transition were determined with the uncertainty of about 100 kHz. The obtained hyperfine splittings were fitted by the four term Hamiltonian and we showed vibrational dependences of the hyperfine constants.