An atom in a laser field

Nikolai L. Manakov, Vitalii D Ovsiannikov, Л. П. Рапопорт

Z. Ficek, Mohamed Ridza Wahiddin

In quantum optical problems involving the interaction of atoms with laser fields, the atoms are usually considered being stationary during the interaction. Since every photon has a momentum, the atomic momentum (motion) can be changed in the process of absorption and emission of photons. This may force a stationary atom to move or to change momentum of an already moving atom. Therefore, the dynamical behaviour of atoms can be varied by the interaction with a radiation field. For a weak driving field, the influence of this field on the atomic motion can be neglected. However, the intensities of laser fields are generally very strong, and then the motion of the atoms can be considerably changed by the laser field. Here, we discuss this aspect, especially the effect of a driving field on the motion of atoms and the atomic momentum distribution. In particular, we will consider diffraction of atoms by a standing-wave laser field due to an exchange of momentum with the photons of the wave, and radiation force on atoms driven by a running-or standing-wave laser field.

Zhao Jian-Gang, Sun Chang-yong, Wen Ling-Hua +1 more

This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose–Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser.

Nikolai B. Delone, В. П. Крайнов

Deshui Yu, Jingbiao Chen

We investigate the influence of atomic transit time $\ensuremath{\tau}$ on the laser linewidth by the quantum Langevin approach. With comparing the bandwidths of cavity mode $\ensuremath{\kappa}$, atomic polarization ${\ensuremath{\gamma}}_{ab}$, and atomic transit broadening ${\ensuremath{\tau}}^{\ensuremath{-}1}$, we study the laser linewidth in different limits. We also discuss the spectrum of fluctuations of output field and the influence of pumping statistics on the output field.The influence of atomic transit time $\ensuremath{\tau}$ on laser field has not been carefully discussed before, to our knowledge. In particular, a laser operating in the region of ${\ensuremath{\gamma}}_{ab}⪡{\ensuremath{\tau}}^{\ensuremath{-}1}⪡\ensuremath{\kappa}∕2$ appears not to have been analyzed in previous laser theories. Our work could be a useful complementarity to laser theory. It is also an important theoretical foundation for the recently proposed active optical atomic clock based on bad-cavity laser mechanism.

Marvin H. Mittleman