Coherent control of bond making: the performance of rationally phase-shaped femtosecond laser pulses*

摘要: The first step in the coherent control of a photoinduced binary reaction is bond making or photoassociation. We have recently demonstrated multiphoton femtosecond photoassociation hot magnesium atoms, using linearly chirped pulses (Levin et al 2015 Phys. Rev. Lett. 114 233003). detected yield photoassociated dimers was enhanced by positively which explained theoretically combination purification and chirp-dependent Raman transitions. could be further pulse optimization resulting with an effective linear chirp sub-pulse structure, where latter allows for exploiting vibrational coherences. Here, we systematically explore efficiency phase-shaped making, employing parametrization spectral phases form cosine functions. find up to order magnitude enhancement compared unshaped transformlimited pulse. highly performing all display overall temporally increasing instantaneous frequency are composed several overlapping sub-pulses. time delay between two sub-pulses fits very well generated intermediate wavepacket. These findings agreement transitions exploitation dynamics as underlying mechanisms.