Laser cooling of a diatomic moleculeDavid P. DeMille, Yale University, DMR 0653377

It has been roughly three decades since laser cooling techniques produced ultracold atoms, leading to rapid advances in many areas. Unfortunately laser cooling has not yet been extended to molecules because of their complex internal structure. However, this same complexity makes ultracold molecules potentially useful for a wide range of applications including quantum computation, quantum simulation, ultracold chemistry, and precision measurement. In the last year we have demonstrated the first laser cooling of a molecule. Examples of our results are shown below. We have observed both Doppler and Sisyphus laser cooling, and we expect to use our techniques to produce trapped, ultracold molecules within the next year.

Molecular beam profile under Doppler (red) and Sisyphus (blue) laser cooling conditions, and when unperturbed (black). The transverse temperature of the beam is indicated for each case. As shown under both Doppler and Sisyphus cooling conditions, the molecular beam width is substantially reduced, indicating cooling of the molecular beam. Sisyphus cooling produces a much colder (narrower) molecular beam than Doppler cooling.

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Unperturbed Doppler cooled

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Unperturbed Sisyphus cooled

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Doppler Cooled~ 5mK

Unperturbed~ 50mK

Sisyphus Cooled~ 300 K

Unperturbed~ 50mK

A Novel Approach to Controlling Coherence Using the Internal Dynamics of Strong Pi Pulses

David P. DeMille, Yale University, DMR 0653377

• Controlling coherence is essential for Quantum Information Physics, and beyond.

• The tiny difference between hard Pi pulses and their delta-function approximation is exploited to produce a new class of spin echoes, with promising applications.

• Extreme Line-Narrowing! Applied to Silicon powder, the Si-29 NMR linewidth (left inset, red) is reduced by a factor of ~70,000 (right inset, black fit to blue data).

A Novel Approach to Controlling Coherence Using the Internal Dynamics of Strong Pi Pulses

David P. DeMille, Yale University, DMR 0653377

• Broader Impacts: Magnetic Resonance Imaging (MRI) typically uses the signal from just a single isotope of Hydrogen (H-1) in liquid water.

• Our new pulse sequences make “the MR spectrum of a solid look like that of a liquid”, enabling MRI of solids with higher spatial resolution and signal-to-noise.

• Some applications: Phosphorus-31 MRI of hard (bone mineral) and soft (cell membrane) tissues. E.g., P-31 MRI of two small pieces of bovine cortical bone---

Left: Surface plot of a 3D image. Note the 1.1mm gap and a 343µm hole in the top bone.

Right: A 2D slice (82µm thick) through the 3D image.