Theory of the Kapitza-Dirac diffraction effect.

Spin dynamics in the Kapitza-Dirac effect.

Electron spin dynamics in Kapitza-Dirac scattering from a standing laser wave of high frequency and high intensity is studied. We develop a fully relativistic quantum theory of the electron motion based on the time-dependent Dirac equation. Distinct spin dynamics, with Rabi oscillations and complete spin-flip transitions, is demonstrated for Kapitza-Dirac scattering involving three photons in a...

Kapitza-Dirac diffraction without standing waves: diffraction without a grating?

We discuss electron diffraction from two counterpropagating light waves with two different frequencies. We show that, even though these waves do not form a standing wave, electron diffraction similar to the conventional Kapitza-Dirac effect, i.e., scattering on a standing wave, is still possible. The nonlinear response of the electron to the laser fields creates a stationary diffraction grating...

Illuminating the Kapitza-Dirac Effect with Electron Matter Optics [Colloquium]

Momentum Transfer to Atoms by Absorption and Emission of Radiation

We report on measurement of momentum transfer to an atomic sodium beam by a standingwave laser field. Experiments were performed in two regimes: 1) the regime in which spontaneous emission is negligible; and 2) the regime in which the effects of spontaneous decay dominate the momentum transfer process. In the first regime, we observe diffraction of the atomic beam: the near-resonant Kapitza-Dir...

Bragg scattering of free electrons using the Kapitza-Dirac effect.

Bragg scattering has been observed for free electrons using a standing wave of light. Both the rocking curve and the angular electron distribution have been measured. The results of a numerical simulation to the Schrödinger equation are consistent with our experimental data. Unlike the diffraction regime which uses thin crystals, the Bragg regime requires the use of thick crystals. We point out...