Slow, Continuous Beams of Large Gas Phase Molecules

Cold, continuous, high flux beams of benzonitrile, fluorobenzine, and anisole have been created. Buffer-gas cooling with a cryogenic gas provides the cooling and slow forward beam velocities. The beam of benzonitrile was measured to have a forward velocity peaked at 67 $\pm 5$ m s$^{-1}$, and a continuous flux of $10^{15}$ molecules s$^{-1}$. These beams provide a continuous source for high resolution spectroscopy, and provide an attractive starting point for further spatial manipulation of such molecules, including eventual trapping

Cooling and Collisions of Large Gas Phase Molecules

Cold and dense samples of naphthalene $(C_{10}H_8)$ are produced using buffer gas cooling in combination with rapid, high flow molecule injection. The observed naphthalene density is $n \approx 10^{11} cm_{−3}$ over a volume of a few $cm^3$ at a temperature of 6 K. We observe naphthalene–naphthalene collisions through two-body loss of naphthalene with a loss cross section of $\sigma_{\Lambda-\Lambda} = 1.4 × 10^{-14} cm^2$. Analysis is presented that indicates that this combination of techniques will be applicable to many comparably sized molecules. This technique can also be combined with cryogenic beam methods to produce cold, high flux, continuous molecular beams.Physic

Reviews

The following publications have been reviewed by the mentioned authors;CDT - Projects and Approaches by David Barlex and Richard Kimbell, reviewed by M. PattersonControl Technology (second edition) by Hodder & Stoughton, reviewed by John CaveGraphic Handbook. An Introduction to design and printing for the non-specialist by Richard McCann, reviewed by Lesley LordEngineering Technology by Liam Hennessy and Lawrence Smyth, reviewed by Stan ShawJoin in and Spin by Thames Valley, reviewed by Dorothea KaySchooling for the Dole: The New Vocationalism by Inge Bates, John Clark, Philip Cohen, Dan Finn, Robert Moore and Paul Willis, reviewed by John EgglestonGirls into Science and Technology by Judith Whyte, reviewed by John Egglesto

Realization of Coherent Optically Dense Media via Buffer-Gas Cooling

We demonstrate that buffer-gas cooling combined with laser ablation can be used to create coherent optical media with high optical depth and low Doppler broadening that offers metastable states with low collisional and motional decoherence. Demonstration of this generic technique opens pathways to coherent optics with a large variety of atoms and molecules. We use helium buffer gas to cool 87Rb atoms to below 7 K and slow atom diffusion to the walls. Electromagnetically induced transparency (EIT) in this medium allows for 50% transmission in a medium with initial OD >70 and for slow pulse propagation with large delay-bandwidth products. In the high-OD regime, we observe high-contrast spectrum oscillations due to efficient four-wave mixing.Comment: 4 pages, 4 figures. V2: modified title, abstract, introduction, conclusion; added references; improved theoretical fit in figure 3(b); shortened slow light theory description; clarified simplicity of apparatus. Final version as published in Phys. Rev.