Directional Quantum-Controlled Chemistry: Generating Aligned Ultracold Molecules via Photoassociation

Abstract

Photoassociation of ultracold atoms is shown to lead to alignment of the product molecules along the excitation laser polarization axis. We theoretically investigate pulsed photoassociation of ${}^{87}Rb$ atoms into a specific weakly-bound level of the a ${}^3{\Sigma }_u^{+}$ metastable electronic state and find both stationary and time-dependent field-free alignment. Although a transform-limited pulse yields significant alignment, a frequency-chirped pulse dramatically enhances the molecular formation rate at the cost of a slight decrease in the alignment. Employing multiple pulses synchronized with the vibrational and rotational periods leads to coherent enhancement of both population and alignment of the target state.

References in corpus (4)

• Field-free orientation of CO molecules by femtosecond two-color laser fields
• Coherent Control of Bond Making
• Generation of Arbitrary Frequency Chirps with a Fiber-Based Phase Modulator and Self-Injection-Locked Diode Laser
• Probing the axis alignment of an ultracold spin-polarized ${\text{Rb}}_2$ molecule