Cold molecules in pulsed optical lattices

We review recent theoretical studies on the dynamics of molecules in pulsed optical lattices. These lattices are periodic potential wells formed by the interaction between two counter propagating far-off resonant optical fields and the molecules. We show that the molecules can be manipulated in both constant velocity and accelerating lattices for a number of applications. We first study a molecular optical mirror through the reflections of molecules by a stationary optical lattice and show that the reflectivity can be significantly improved by optimizing the pulse duration. When reflection occurs from a moving lattice, we show that molecules can brought to rest when the lattice velocity is half the molecular velocity, demonstrating a new and efficient method for creating slow cold molecules. We further describe a microlinear accelerator for molecules produced by an accelerating optical lattice, which is achieved by frequency chirping one of the two optical fields. The molecules trapped by the potential wells of the lattice are accelerated to high velocities (10–100 km/s) over micron-size distance within nanosecond time scales. When the lattice is decelerated, the trapped molecules can be slowed to zero velocity, offering an alternate method for producing slow cold molecules. Molecules that are not trapped in the accelerating lattice can be temporarily localized around a characteristic velocity, which is uniquely dependent on the mass-to-polarizability ratio. We show that this feature can be used for a new form of time-of-flight mass spectrometry for chemical analysis of a mixture.