Velocity control of an Yb beam by a frequency-doubled mode-locked laser

Watanabe, Masayoshi; Ohmukai, Ryuzo; Tanaka, U.; Hayasaka, Kazuhiro; Imajo, Hidetsuka; Urabe, Shinji

doi:10.1364/josab.13.002377

Cited by 26 publications

(15 citation statements)

References 14 publications

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“…Initially, continuous laser radiation was used for this purpose, but now pulsed laser applications for cooling [4][5][6][7][8][9][10][11] and trapping [12][13][14][15][16] of atoms and molecules are also discussed. In [4] the deceleration of a Na beam by a counterpropagating beam of a mode-locked laser and the appearance of negative velocity atoms were observed for the first time.…”

Section: Introductionmentioning

confidence: 99%

“…The next step to produce cool atoms by pulsed laser radiation was made in [5], where a two-mode laser beam, copropagating with the atomic beam and counterpropagating to the mode-locked laser beam, was used to stop the deceleration process at a defined atomic velocity. In [6] an Yb atomic beam was decelerated with the use of a light beam of a mode-locked Ti:sapphire laser. The first theoretical study of laser cooling of atoms by counterpropagating laser pulses was carried out in [7], where the interaction of atoms with weak laser pulses was analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Cooling and trapping of atoms and molecules by counterpropagating pulse trains

et al. 2014

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We discuss a possible one-dimensional trapping and cooling of atoms and molecules due to their nonresonant interaction with counterpropagating light pulse trains. The counterpropagating pulses form a one-dimensional trap for atoms and molecules and a properly chosen carrier frequency detuning from the transition frequency of the atoms or molecules keeps the temperature of the atomic or molecular ensemble close to the Doppler cooling limit. The calculation by the Monte Carlo wave-function method is carried out for the two-level and three-level schemes of the atom's and the molecule's interaction with the field, respectively. The models discussed are applicable to atoms and molecules with almost diagonal Frank-Condon factor arrays. Illustrative calculations are carried out for ensemble-averaged characteristics for sodium atoms and SrF molecules in the trap. The potential for the nanoparticle light pulses's trap formed by counterpropagating light pulse trains is also discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cooling and trapping of atoms and molecules by counterpropagating pulse trains

et al. 2014

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“…The deposited structures of the Yb atoms can be examined with a variety of microscopic techniques. We can potentially take advantage of various precise manipulation methods of Yb atoms [9][10][11][12][13][14][15] and even use the Bose-Einstein condensation of Yb atoms [16] for engineering applications. Following the typical AN procedure, the collimated 174 Yb atoms were focused to lines separated by half of the wavelength onto a substrate using nano-lens arrays for atoms made of the intense optical standing wave (SW).…”

Section: Introductionmentioning

confidence: 99%

Atomic nanofabrication using an ytterbium atomic beam

Ohmukai

Urabe

Watanabe

2004

Science and Technology of Advanced Materials

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Highly parallel and periodically narrow lines of ytterbium (Yb) atoms were successfully produced on a substrate using a near resonant laser light and direct-write atomic nanofabrication. Yb atoms are a promising material for nanofabrication using atom optics particularly due to their electric conductivity, the laser wavelength required for their manipulation, and the vapor pressure required for their fabrication. Collimated 174 Yb atoms were channeled into the nodes of an optical standing wave with dipole force and then deposited onto a substrate. We clearly observed a grating pattern of Yb atoms fabricated on a substrate with a line separation of approximately 200 nm after examining the surface of the substrate with an atomic force microscope. This is the first demonstration of nanofabrication using the atom-optical approach with Yb atoms. q

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“…To increase the velocity capture range, several laser cooling methods were investigated that modulate or effectively broaden a narrow-band laser [3,4,5,6,7,8]. Modelocked pulsed lasers have been used to narrow the velocity distribution of atomic beams within several velocity classes given by the bandwidth of each spectral component of the frequency comb [9,10]. In this letter we report the demonstration of Doppler laser cooling of trapped atoms with individual broadband light pulses from a modelocked laser.…”

mentioning

confidence: 99%

“…Thus, by the time the next laser pulse arrives, the excited state population is only about 2%. This cooling process is then primarily due to absorbing single photons from individual pulses, and not due to an optical frequency comb effect [9,10,24]. For optimal cooling of a given atomic species, the pulsed laser repetition rate should be of the order of the atom's excited state linewidth, while the energy in each laser pulse should correspond to P exc ≃ 1…”

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confidence: 99%

Broadband laser cooling of trapped atoms with ultrafast pulses

et al. 2006

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We demonstrate broadband laser cooling of atomic ions in an rf trap using ultrafast pulses from a modelocked laser. The temperature of a single ion is measured by observing the size of a timeaveraged image of the ion in the known harmonic trap potential. While the lowest observed temperature was only about 1 K, this method efficiently cools very hot atoms and can sufficiently localize trapped atoms to produce near diffraction-limited atomic images.PACS numbers: 32.80. Pj, 42.50.Vk Laser cooling of atoms [1,2] has become a cornerstone of modern day atomic physics. Doppler cooling and its many extensions usually involve narrow-band, continuous-wave lasers that efficiently cool atoms within a narrow velocity range (∼ 1 m/s) that corresponds to the radiative linewidth of a typical atomic transition. To increase the velocity capture range, several laser cooling methods were investigated that modulate or effectively broaden a narrow-band laser [3,4,5,6,7,8]. Modelocked pulsed lasers have been used to narrow the velocity distribution of atomic beams within several velocity classes given by the bandwidth of each spectral component of the frequency comb [9,10]. In this letter we report the demonstration of Doppler laser cooling of trapped atoms with individual broadband light pulses from a modelocked laser.To efficiently capture and cool high-velocity atoms, it is necessary to achieve a laser bandwidth large enough to cover the large range of atomic Doppler shifts. For example, Cd + ions used in this experiment are initially created with an average kinetic energy of order 1 eV, which corresponds to an average velocity of about 1300 m/s and a Doppler shift of ∆ D ∼ 36 GHz. Power broadening an atomic transition (saturation intensity I s and natural linewidth γ) would require a laser intensity of2 , which can be prohibitively high. For Cd + (γ/2π ≃ 50MHz, I s ≃ 5000W/m 2 ) this requires I ∼ 10 10 W/m 2 . Modulating a narrow-band laser to generate high bandwidths would allow for significantly less laser power, but it is technically difficult to generate a 100 GHz wide modulation spectrum [4]. On the other hand, an ultrafast laser whose pulse is a few picoseconds long will naturally have a bandwidth in the above range, as well as sufficient intensity to excite the transition.The laser cooling rate depends critically on the photon scatter rate, which for a pulsed laser can be no larger than the laser repetition rate R (about 80 MHz for a typical modelocked laser), given that the atom is excited with unit probability by each pulse. We assume that once excited, the atom decays back to the ground state faster than the time period of the modelocked pulse train 1/R. In this case, the atom has little memory between pulses, or equivalently, the absorption spectrum is a single broad line of width ∆ ∼ 1/τ (τ is the pulse duration) and the frequency comb of spacing R has very little contrast.The equilibrium temperature for broadband pulsed laser cooling of trapped atoms is expected to scale approximately with the laser bandwidth ∆, a...

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Velocity control of an Yb beam by a frequency-doubled mode-locked laser

Cited by 26 publications

References 14 publications

Cooling and trapping of atoms and molecules by counterpropagating pulse trains

Cooling and trapping of atoms and molecules by counterpropagating pulse trains

Atomic nanofabrication using an ytterbium atomic beam

Broadband laser cooling of trapped atoms with ultrafast pulses

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