technology,2 and such cells have already been used in several .... After 300 Uts of this postcooling, the temperature of the ... were able to recollect these atoms in 1.5 ms (rather than wait the -1 s .... Model 699-21. This information is for tech-.
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OPTICS LETTERS / Vol. 18, No. 14 / July 15, 1993
Improved hyperfine measurements of the Na 5p excited state
through frequency-controlled Dopplerless spectroscopy in a Zeeman magneto-optic laser trap M. Zhu, C. W. Oates, and J. L. Hall
JointInstitutefor LaboratoryAstrophysics,Universityof Coloradoand NationalInstituteof Standardsand Technology, Boulder, Colorado 80309-0440 Received March 19, 1993
We report what is to our knowledge the first Dopplerlesshigh-resolution optical spectroscopybased on unperturbed atoms left nearly at rest when a vapor cell magneto-optic trap is switched off. A A = 285 nm beam excited the
3s - 5p transition in our sample of laser trapped/cooledNa atoms from which we collectedfluorescence. Excitedstate 5 2P3/2and 5 2P1 /2 hyperfine interaction constants are derived with 4- and 47-fold increases, respectively, in accuracy.
Future prospects for vapor-cell-based optical spectroscopy and frequency standards are considered.
The remarkable capabilities of laser trapping and cooling techniques with neutral atoms' have made available a new regime of experiments. Highdensity samples (>1010 atoms/cm 3 ) can now be produced with extremely narrow velocity widths centered around zero velocity, thus permitting extremely high-resolution measurements. Moreover, the magneto-optic trap in a vapor cell permits inexpensive and convenient access to this revolutionary technology,2 and such cells have already been used in several experiments.3 - 6 One of the most promising applications of this new technology lies in the development of new optical atomic frequency standards. 7 As a step in this direction, we present what is to our knowledge the first Dopplerless high-precision optical spectroscopic measurement of unperturbed atoms with the vapor cell as our source of atomic samples. We have measured the hyperfine splitting constants in the 5p excited state of Na with a significant increase in precision through optical-frequency techniques. Because laser trapping/cooling techniques efficiently compress the Doppler width from 2.5 GHz to < 1 MHz for the trapped atoms, we did not need to use multiple-beam (first-order) Doppler-free spectroscopic techniques previously required in order to resolve megahertz-level splittings. Instead we used only a single-pass probe to perform what might be called Dopplerless spectroscopy. With atomic kinetic temperatures measured in the sub-millikelvin domain, even the Doppler shifts will be
