Laser Pulse Shaping for State-Selective Excitation

Abstract

Our research focuses on the design and application of pulse sequences with enhanced control over the radiation field (tailored phase and amplitude modulated pulses or phase shifted sequences) to produce simple and interpretable molecular states in a wide variety of applications (nuclear magnetic resonance, magnetic resonance imaging, and laser spectroscopy). Experimentally generating such “ultracoherent transient” laser pulse sequences with complete control of pulse shapes, phases, and delays previously presented a formidable challenge, but theoretical work has shown that such capabilities would enhance multiphoton pumping1,2, selectively excite high vibrational levels of the electronic ground stated3 or measure contributions from transition electric dipole-dipole interactions in condensed phases4. There have even been recent calculations which show that a well-defined phase relation between multiple lasers5 or shaped laser pulses6,7 can promote state-selective chemistry. In this paper we will present the first results from an apparatus which lets us simultaneously tailor pulse shape and control phase shifts on a picosecond timescale, and compare the technological state-of-the-art in various laboratories to the level of sophistication necessary for experimental realization of these concepts.