We propose a laser cooling method for atomic species whose level structure makes traditional laser cooling difficult. For instance, laser cooling of hydrogen requires single-frequency vacuum-ultraviolet light, while multielectron atoms need single-frequency light at many widely separated frequencies. These restrictions can be eased by laser cooling on two-photon transitions with ultrafast pulse trains. Laser cooling of hydrogen, antihydrogen, and many other species appears feasible, and extension of the technique to molecules may be possible.We propose a laser cooling method for atomic species whose level structure makes traditional laser cooling difficult. For instance, laser cooling of hydrogen requires single-frequency vacuum-ultraviolet light, while multielectron atoms need single-frequency light at many widely separated frequencies. These restrictions can be eased by laser cooling on two-photon transitions with ultrafast pulse trains. Laser cooling of hydrogen, antihydrogen, and many other species appears feasible, and extension of the technique to molecules may be possible.

arXiv:physics/0512065Physical Review AJun 13, 200667 citations

Laser Cooling of Atoms

Hidekazu Hachisu

Nihon Kikai Gakkaishi/Journal of the Japan Society of Mechanical EngineersJan 1, 20090 citations

Pulsed Sisyphus Scheme for Laser Cooling of Atomic (Anti)Hydrogen

Saijun Wu, Roger C. Brown, William D. Phillips +1 more

We propose a laser cooling technique in which atoms are selectively excited to a dressed metastable state whose light shift and decay rate are spatially correlated for Sisyphus cooling. The case of cooling magnetically trapped (anti)hydrogen with the 1S-2S-3P transitions by using pulsed ultraviolet and continuous-wave visible lasers is numerically simulated. We find a number of appealing features including rapid three-dimensional cooling from ∼1 K to recoil-limited, millikelvin temperatures, as well as suppressed spin-flip loss and manageable photoionization loss.We propose a laser cooling technique in which atoms are selectively excited to a dressed metastable state whose light shift and decay rate are spatially correlated for Sisyphus cooling. The case of cooling magnetically trapped (anti)hydrogen with the 1S-2S-3P transitions by using pulsed ultraviolet and continuous-wave visible lasers is numerically simulated. We find a number of appealing features including rapid three-dimensional cooling from ∼1 K to recoil-limited, millikelvin temperatures, as well as suppressed spin-flip loss and manageable photoionization loss.

arXiv:1101.3602Physical Review LettersMay 24, 201122 citations

Production of ultracold hydrogen and deuterium via Doppler-cooled Feshbach molecules

Ian C. Lane

A counterintuitive scheme to produce ultracold hydrogen via fragmentation of laser cooled diatomic hydrides is presented where the final atomic H temperature is inversely proportional to the mass of the molecular parent. In addition, the critical density for formation of a Bose-Einstein condensate (BEC) at a fixed temperature is reduced by a factor $({m}_{H}/\phantom{\rule{0.0pt}{0ex}}{m}_{MH}{)}^{3/2}$ over directly cooled hydrogen atoms. The narrow Feshbach resonances between a $^{1}S_{0}$ atom and hydrogen are well suited to a tiny center of mass energy release necessary during fragmentation. With the support of ab initio quantum chemistry, it is demonstrated that BaH is an ideal diatomic precursor that can be laser cooled to a Doppler temperature of $\ensuremath{\sim}26\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{K}$ with just two rovibronic transitions, the simplest molecular cooling scheme identified to date. Preparation of a hydrogen atom gas below the critical BEC temperature ${T}_{c}$ is feasible with present cooling technology, with optical pulse control of the condensation process.A counterintuitive scheme to produce ultracold hydrogen via fragmentation of laser cooled diatomic hydrides is presented where the final atomic H temperature is inversely proportional to the mass of the molecular parent. In addition, the critical density for formation of a Bose-Einstein condensate (BEC) at a fixed temperature is reduced by a factor $({m}_{H}/\phantom{\rule{0.0pt}{0ex}}{m}_{MH}{)}^{3/2}$ over directly cooled hydrogen atoms. The narrow Feshbach resonances between a $^{1}S_{0}$ atom and hydrogen are well suited to a tiny center of mass energy release necessary during fragmentation. With the support of ab initio quantum chemistry, it is demonstrated that BaH is an ideal diatomic precursor that can be laser cooled to a Doppler temperature of $\ensuremath{\sim}26\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{K}$ with just two rovibronic transitions, the simplest molecular cooling scheme identified to date. Preparation of a hydrogen atom gas below the critical BEC temperature ${T}_{c}$ is feasible with present cooling technology, with optical pulse control of the condensation process.

arXiv:1311.7081Physical Review AAug 24, 201556 citations

({m}_{H}/\phantom{\rule{0.0pt}{0ex}}{m}_{MH}{)}^{3/2}

over directly cooled hydrogen atoms. The narrow Feshbach resonances between a

^{1}S_{0}

atom and hydrogen are well suited to a tiny center of mass energy release necessary during fragmentation. With the support of ab initio quantum chemistry, it is demonstrated that BaH is an ideal diatomic precursor that can be laser cooled to a Doppler temperature of $\ensuremath{\sim}26\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{K}$ with just two rovibronic transitions, the simplest molecular cooling scheme identified to date. Preparation of a hydrogen atom gas below the critical BEC temperature

{T}_{c}

is feasible with present cooling technology, with optical pulse control of the condensation process.