Sub-Doppler Molecular-Iodine Transitions Near the Dissociation Limit (523-498 NM)
W Y. Cheng, L Chen, T H. Yoon, John L. Hall, Jun Ye
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 and the narrowest linewidth is found to be -40 kHz near 508 nm. The hyperfine-resolved patterns are found to be largely modified towards the dissociation limit. The observed excellent signal-to-noise ratio should lead to high quality optical frequency standards that are better than the popular 532 nm system.