Absolute frequencies, linewidths, and hyperfine structures of iodine transitions near the dissociation limit (523 to 498 NM)

A widely tunable and high-resolution spectrometer based on a frequency doubled Ti:sapphire laser is used to explore sub-Doppler transitions of iodine molecules in the wavelength range of 523 - 498 nm. The wavelength-dependence of the hyperfine transition linewidth of iodine is mapped out in this region. Towards the dissociation limit near 500 nm, the hyperfine-resolved patterns are found to be largely modified. A femtosecond optical comb is used to determine the absolute frequency of the 514.7 nm optical standard with more than a 100-fold improvement in precision.