We discuss the phase-sensitive noise properties of fluorescence emitted by three-level atoms coherently excited by two laser fields, using both undressed and dressed uncoupled-state representations. The occurrence of steady-state squeezing is found to be highly sensitive to relaxation processes between the two-photon resonant levels. For purely radiative decay from the upper level, and no lower-state relaxation, the population is susceptible to coherent population trapping. Near two-photon resonance, the atom is optically pumped into a nonabsorbing (trapped) superposition state, which, although it reduces upper-level population, also leads to an interference cancellation of dipole moments and to suppression of squeezing. Lower-level relaxation unbalances this interference and restores the squeezing to some extent. Transient squeezing is also predicted in the time-dependent fluorescence.We discuss the phase-sensitive noise properties of fluorescence emitted by three-level atoms coherently excited by two laser fields, using both undressed and dressed uncoupled-state representations. The occurrence of steady-state squeezing is found to be highly sensitive to relaxation processes between the two-photon resonant levels. For purely radiative decay from the upper level, and no lower-state relaxation, the population is susceptible to coherent population trapping. Near two-photon resonance, the atom is optically pumped into a nonabsorbing (trapped) superposition state, which, although it reduces upper-level population, also leads to an interference cancellation of dipole moments and to suppression of squeezing. Lower-level relaxation unbalances this interference and restores the squeezing to some extent. Transient squeezing is also predicted in the time-dependent fluorescence.

Journal of the Optical Society of America BOct 1, 198731 citations

Two-Photon Coherent Atomic Absorption of Multiple Laser Beams

Ming-Chiang Li

Bulletin of the American Physical SocietyMay 18, 20060 citations

Theory of coherent two-photon absorption

NILOY KUMAR DUTTA

Physics Letters ANov 1, 19785 citations

Photon antibunching and non-Poissonian fluorescence of a single three-level ion

Michael Schubert, Ingo Siemers, R. Blatt +2 more

The photon pair correlation in the laser-excited fluorescence of a single trapped and cooled ${\mathrm{Ba}}^{+}$ ion shows antibunching and, in addition, novel nonclassical phenomena absent in the fluorescence of two-level atoms. They include excessive transient values of the correlation caused by optical pumping, and temporally extended sub-Poissonian photon emission probability which arises from the transient excitation of nonabsorbing Raman coherence. The fluorescence also displays sub-Poissonian photon statistics.The photon pair correlation in the laser-excited fluorescence of a single trapped and cooled ${\mathrm{Ba}}^{+}$ ion shows antibunching and, in addition, novel nonclassical phenomena absent in the fluorescence of two-level atoms. They include excessive transient values of the correlation caused by optical pumping, and temporally extended sub-Poissonian photon emission probability which arises from the transient excitation of nonabsorbing Raman coherence. The fluorescence also displays sub-Poissonian photon statistics.

Physical Review LettersMay 18, 199274 citations

Coherent two-photon absorption of ultra-short light pulses

V. M. Arutyunyan, N. Sh. Badanyan, A. A. Chakhmakhchyan +1 more

OptSpJan 1, 19880 citations

Laser Cooling below the One-Photon Recoil Energy by Velocity-Selective Coherent Population Trapping

Alain Aspect, E. Arimondo, Robin Kaiser +2 more

We present a new laser-cooling scheme based on velocity-selective optical pumping of atoms into a nonabsorbing coherent superposition of states. This method has allowed us to achieve transverse cooling of metastable $^{4}\mathrm{He}$ atoms to a temperature of 2 \ensuremath{\mu}K, lower than both the usual Doppler cooling limit (23 \ensuremath{\mu}K) and the one-photon recoil energy (4 \ensuremath{\mu}K). The corresponding de Broglie wavelength (1.4 \ensuremath{\mu}m) is larger than the atomic-transition optical wavelength.We present a new laser-cooling scheme based on velocity-selective optical pumping of atoms into a nonabsorbing coherent superposition of states. This method has allowed us to achieve transverse cooling of metastable $^{4}\mathrm{He}$ atoms to a temperature of 2 \ensuremath{\mu}K, lower than both the usual Doppler cooling limit (23 \ensuremath{\mu}K) and the one-photon recoil energy (4 \ensuremath{\mu}K). The corresponding de Broglie wavelength (1.4 \ensuremath{\mu}m) is larger than the atomic-transition optical wavelength.

Physical Review LettersAug 15, 1988865 citations

The photon pair correlation in the laser-excited fluorescence of a single trapped and cooled

{\mathrm{Ba}}^{+}

ion shows antibunching and, in addition, novel nonclassical phenomena absent in the fluorescence of two-level atoms. They include excessive transient values of the correlation caused by optical pumping, and temporally extended sub-Poissonian photon emission probability which arises from the transient excitation of nonabsorbing Raman coherence. The fluorescence also displays sub-Poissonian photon statistics.

^{4}\mathrm{He}

atoms to a temperature of 2 \ensuremath{\mu}K, lower than both the usual Doppler cooling limit (23 \ensuremath{\mu}K) and the one-photon recoil energy (4 \ensuremath{\mu}K). The corresponding de Broglie wavelength (1.4 \ensuremath{\mu}m) is larger than the atomic-transition optical wavelength.