In molecular iodine, and most other gas-phase molecules as well, generation of a π/2 or π pulse is theoretically impossible. This result can be understood by analogy with microwave spectroscopy, since the rotational contribution to the transition dipole moment is an explicit function of the projection of the total angular momentum F = J + I along the electric-field axis. The only solution is the generation of phase-modulated pulses that inherently compensate for Rabi-frequency inhomogeneity. We present theoretical and experimental evidence that crafted phase- and amplitude-modulated pulse shapes can excite a uniform, localized, and nearly complete inversion in nuclear magnetic resonance and laser spectroscopy.
© 1986 Optical Society of America
W. S. Warren, J. L. Bates, M. A. McCoy, M. Navratil, and L. Mueller, "There were no pi pulses in iodine vapor: crafted pulses to compensate for Rabi-frequency inhomogeneities," J. Opt. Soc. Am. B 3, 488-492 (1986)