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Title: Low-temperature high-density magneto-optical trapping of potassium using the open 4S{yields}5P transition at 405 nm

Abstract

We report the laser cooling and trapping of neutral potassium on an open transition. Fermionic {sup 40}K is captured using a magneto-optical trap (MOT) on the closed 4S{sub 1/2}{yields}4P{sub 3/2} transition at 767 nm and then transferred, with high efficiency, to a MOT on the open 4S{sub 1/2}{yields}5P{sub 3/2} transition at 405 nm. Because the 5P{sub 3/2} state has a smaller linewidth than the 4P{sub 3/2} state, the Doppler limit is reduced from 145 {mu}K to 24 {mu}K, and we observe temperatures as low as 63(6) {mu}K. The density of trapped atoms also increases, due to reduced temperature and reduced expulsive light forces. We measure a two-body loss coefficient of {beta}=1.4(1)x10{sup -10} cm{sup 3}/s near saturation intensity, and estimate an upper bound of 8x10{sup -18} cm{sup 2} for the ionization cross section of the 5P state at 405 nm. The combined temperature and density improvement in the 405 nm MOT is a twenty-fold increase in phase-space density over our 767 nm MOT, showing enhanced precooling for quantum gas experiments. A qualitatively similar enhancement is observed in a 405 nm MOT of bosonic {sup 41}K.

Authors:
; ; ; ;  [1];  [1]
  1. Department of Physics, CQIQC, and Institute for Optical Sciences, University of Toronto, M5S1A7 (Canada)
Publication Date:
OSTI Identifier:
22095646
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 84; Journal Issue: 6; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; COOLING; CROSS SECTIONS; ENERGY-LEVEL TRANSITIONS; FERMIONS; IONIZATION; LASER RADIATION; MAGNETO-OPTICAL EFFECTS; P STATES; PHASE SPACE; POTASSIUM; POTASSIUM 40; POTASSIUM 41; S STATES; TRAPPING; TRAPS; TWO-BODY PROBLEM; VISIBLE RADIATION

Citation Formats

McKay, D. C., Jervis, D., Fine, D. J., Simpson-Porco, J. W., Edge, G. J. A., Thywissen, J. H., and Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1Z8. Low-temperature high-density magneto-optical trapping of potassium using the open 4S{yields}5P transition at 405 nm. United States: N. p., 2011. Web. doi:10.1103/PHYSREVA.84.063420.
McKay, D. C., Jervis, D., Fine, D. J., Simpson-Porco, J. W., Edge, G. J. A., Thywissen, J. H., & Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1Z8. Low-temperature high-density magneto-optical trapping of potassium using the open 4S{yields}5P transition at 405 nm. United States. https://doi.org/10.1103/PHYSREVA.84.063420
McKay, D. C., Jervis, D., Fine, D. J., Simpson-Porco, J. W., Edge, G. J. A., Thywissen, J. H., and Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1Z8. 2011. "Low-temperature high-density magneto-optical trapping of potassium using the open 4S{yields}5P transition at 405 nm". United States. https://doi.org/10.1103/PHYSREVA.84.063420.
@article{osti_22095646,
title = {Low-temperature high-density magneto-optical trapping of potassium using the open 4S{yields}5P transition at 405 nm},
author = {McKay, D. C. and Jervis, D. and Fine, D. J. and Simpson-Porco, J. W. and Edge, G. J. A. and Thywissen, J. H. and Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1Z8},
abstractNote = {We report the laser cooling and trapping of neutral potassium on an open transition. Fermionic {sup 40}K is captured using a magneto-optical trap (MOT) on the closed 4S{sub 1/2}{yields}4P{sub 3/2} transition at 767 nm and then transferred, with high efficiency, to a MOT on the open 4S{sub 1/2}{yields}5P{sub 3/2} transition at 405 nm. Because the 5P{sub 3/2} state has a smaller linewidth than the 4P{sub 3/2} state, the Doppler limit is reduced from 145 {mu}K to 24 {mu}K, and we observe temperatures as low as 63(6) {mu}K. The density of trapped atoms also increases, due to reduced temperature and reduced expulsive light forces. We measure a two-body loss coefficient of {beta}=1.4(1)x10{sup -10} cm{sup 3}/s near saturation intensity, and estimate an upper bound of 8x10{sup -18} cm{sup 2} for the ionization cross section of the 5P state at 405 nm. The combined temperature and density improvement in the 405 nm MOT is a twenty-fold increase in phase-space density over our 767 nm MOT, showing enhanced precooling for quantum gas experiments. A qualitatively similar enhancement is observed in a 405 nm MOT of bosonic {sup 41}K.},
doi = {10.1103/PHYSREVA.84.063420},
url = {https://www.osti.gov/biblio/22095646}, journal = {Physical Review. A},
issn = {1050-2947},
number = 6,
volume = 84,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2011},
month = {Thu Dec 15 00:00:00 EST 2011}
}