Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

High-Resolution Two-Photon Spectroscopy with Picosecond Light Pulses

J. N. Eckstein, A. I. Ferguson, Theodor W. Hänsch

Published Mar 27, 1978• 298 citations
Publisher

Abstract

We have demonstrated the feasibility of Doppler-free two-photon spectroscopy with a train of picosecond standing-wave light pulses from a synchronously pumped mode-locked cw dye laser. The actively controlled mode spectrum provides a means for accurate measurements of large frequency intervals. From a multipulse spectrum of the sodium $3s\ensuremath{-}4d$ transition we have determined a new value of the $4d$ fine-structure splitting, 1028\ifmmode\pm\else\textpm\fi{}0.4 MHz.

DOI
10.1103/physrevlett.40.847

Related papers

Fine Structure of Na 4dD2 Using High-Resolution Two-Photon Spectroscopy

David E. Pritchard, J. Apt, Theodore W. Ducas

We have measured the fine-structure splitting of the $4d^{2}D$ state of neutral sodium using high-resolution, cw, simultaneous two-photon excitation from the $3s^{2}S$ ground state. Sodium atoms in an atomic beam were excited by a single-mode, cw, tunable dye laser, and the resonance was detected by monitoring the decay fluorescence from the excited state. The fine structure of the $4d^{2}D$ state was well resolved and measured to be ${\ensuremath{\Delta}}_{\mathrm{fs}}=1025\ifmmode\pm\else\textpm\fi{}6$ MHz.

Physical Review Letters•Mar 25, 1974•84 citations

Stark-effect study of excited states in sodium using two-photon spectroscopy

Roberta Hawkins, W. T. Hill, Frank V. Kowalski +2 more

We have used two-photon absorption from counterpropagating laser beams of different frequencies to measure Stark shifts and splittings of the $6^{2}S$, $7^{2}S$, $8^{2}S$, $5^{2}D$, and $6^{2}D$ states in sodium. Beams from a fixed-frequency, single-mode ${\mathrm{Ar}}^{+}$ laser and a tunable, single-frequency cw dye laser were focussed into a coarse sodium atomic beam and the fluorescence was monitored. The collimation of the atomic beam reduced the residual Doppler width inherent in using two different frequencies. Using the two lasers allowed two-photon transitions to be observed at frequencies unattainable with the dye laser alone, and enhanced the transition rates due to the near resonance of the dye laser with the strong Na $3^{2}S\ensuremath{\rightarrow}3^{2}P$ transition. Our experimental results for the scalar and tensor polarizabilities, ${\ensuremath{\alpha}}_{0}$ and ${\ensuremath{\alpha}}_{2}$, agree with calculations in the Bates and Damgaard Coulomb approximation within 2% for ${\ensuremath{\alpha}}_{0}$ and 9% for ${\ensuremath{\alpha}}_{2}$. As a by-product the hyperfine-interaction constants $a$ for the $S$ states and the fine-structure intervals $\ensuremath{\delta}\ensuremath{\nu}=\frac{({E}_{\frac{3}{2}}\ensuremath{-}{E}_{\frac{5}{2}})}{h}$ for the $D$ states were obtained.

Physical Review A•Mar 1, 1977•31 citations

Two-photon absorption spectroscopy of highly-excited states of Rb atoms

Y. Kato

Doppler-free two-photon absorption spectroscopy was applied to study highly-excited D states of Rb atoms. Using a cw dye laser as an excitation source, transitions from the ground 5S state to nd 2D states (n=11-32) were observed, the ionization energy of the highest state being only 117cm-1. These D doublets are not inverted. The fine structure splittings of these states do not vary as (neff) -3, nor as n-3. The isotope shift of the 85Rb, 87Rb ground states is found to be 160±12MHz. No pressure broadening was observed for these transitions within the instrumental resolution of 15 MHz.

The Review of Laser Engineering•Jan 1, 1976•0 citations

Quantum beats in forward scattering: subnanosecond studies with a mode-locked dye laser

H. Harde, J. Mlynek, Wulfhard K. Lange +1 more

Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D(1) and D(2), lines were resolved. The ground-state splitting could be determined with an accuracy of better than 10(-3).

Optics Letters•Jun 1, 1981•31 citations

Measurement of the Fine-Structure Splitting of the 4F State in Atomic Sodium Using Two-Photon Spectroscopy with a Resonant Intermediate State

P. F. Liao, John E. Bjorkholm

The fine-structure splitting of the $4F$ state of atomic sodium is determined using the technique of two-photon spectroscopy with a resonant intermediate state. The sensitivity of this Doppler-free technique allows observation of the electric-dipole-forbidden $3S\ensuremath{\rightarrow}4F$ two-photon transition. The $4F$ fine-structure splitting is found to be 229\ifmmode\pm\else\textpm\fi{}4 MHz. Its sign and magnitude are hydrogenic, in complete contrast to the $D$ levels of Na.

Physical Review Letters•Jun 28, 1976•36 citations

Continuous-wave Doppler-free two-photon spectroscopy of high Rydberg states of Ca in the deep blue spectral range

R. Beigang, K. Lugke, Eckart Matthias +1 more

Doppler-free two-photon spectroscopy with cw dye lasers has opened a new dimension of accuracy for investigation of Rydberg states.1

Conference on Lasers and Electro-Optics•Jan 1, 1982•0 citations
We have demonstrated the feasibility of Doppler-free two-photon spectroscopy with a train of picosecond standing-wave light pulses from a synchronously pumped mode-locked cw dye laser. The actively controlled mode spectrum provides a means for accurate measurements of large frequency intervals. From a multipulse spectrum of the sodium 3s\ensuremath−4d3s\ensuremath{-}4d3s\ensuremath−4d transition we have determined a new value of the 4d4d4d fine-structure splitting, 1028\ifmmode\pm\else\textpm\fi{}0.4 MHz.
We have measured the fine-structure splitting of the 4d2D4d^{2}D4d2D state of neutral sodium using high-resolution, cw, simultaneous two-photon excitation from the 3s2S3s^{2}S3s2S ground state. Sodium atoms in an atomic beam were excited by a single-mode, cw, tunable dye laser, and the resonance was detected by monitoring the decay fluorescence from the excited state. The fine structure of the 4d2D4d^{2}D4d2D state was well resolved and measured to be ${\ensuremath{\Delta}}_{\mathrm{fs}}=1025\ifmmode\pm\else\textpm\fi{}6$ MHz.
We have used two-photon absorption from counterpropagating laser beams of different frequencies to measure Stark shifts and splittings of the 62S6^{2}S62S, 72S7^{2}S72S, 82S8^{2}S82S, 52D5^{2}D52D, and 62D6^{2}D62D states in sodium. Beams from a fixed-frequency, single-mode Ar+{\mathrm{Ar}}^{+}Ar+ laser and a tunable, single-frequency cw dye laser were focussed into a coarse sodium atomic beam and the fluorescence was monitored. The collimation of the atomic beam reduced the residual Doppler width inherent in using two different frequencies. Using the two lasers allowed two-photon transitions to be observed at frequencies unattainable with the dye laser alone, and enhanced the transition rates due to the near resonance of the dye laser with the strong Na $3^{2}S\ensuremath{\rightarrow}3^{2}P$ transition. Our experimental results for the scalar and tensor polarizabilities, ${\ensuremath{\alpha}}_{0}$ and ${\ensuremath{\alpha}}_{2}$, agree with calculations in the Bates and Damgaard Coulomb approximation within 2% for ${\ensuremath{\alpha}}_{0}$ and 9% for ${\ensuremath{\alpha}}_{2}$. As a by-product the hyperfine-interaction constants aaa for the SSS states and the fine-structure intervals $\ensuremath{\delta}\ensuremath{\nu}=\frac{({E}_{\frac{3}{2}}\ensuremath{-}{E}_{\frac{5}{2}})}{h}$ for the DDD states were obtained.
Doppler-free two-photon absorption spectroscopy was applied to study highly-excited D states of Rb atoms. Using a cw dye laser as an excitation source, transitions from the ground 5S state to nd 2D states (n=11-32) were observed, the ionization energy of the highest state being only 117cm-1. These D doublets are not inverted. The fine structure splittings of these states do not vary as (neff) -3, nor as n-3. The isotope shift of the 85Rb, 87Rb ground states is found to be 160±12MHz. No pressure broadening was observed for these transitions within the instrumental resolution of 15 MHz.
The fine-structure splitting of the 4F4F4F state of atomic sodium is determined using the technique of two-photon spectroscopy with a resonant intermediate state. The sensitivity of this Doppler-free technique allows observation of the electric-dipole-forbidden $3S\ensuremath{\rightarrow}4F$ two-photon transition. The 4F4F4F fine-structure splitting is found to be 229\ifmmode\pm\else\textpm\fi{}4 MHz. Its sign and magnitude are hydrogenic, in complete contrast to the DDD levels of Na.