Palestrante
Descrição
Methods borrowed from atomic interferometry promise great advances in the development of inertial sensors. One particularly attractive technique translates the gravitational acceleration force into a measurement of the frequency of Bloch oscillations of laser-cooled atoms confined in a vertical stationary light wave. In modern gravimeters, the measurement is destructive and new atomic samples must be prepared for each choice of evolution time. To overcome these destructive measurements, we propose to study a new technique that allows monitoring in vivo Bloch oscillations of strontium atoms. Two key ingredients based on different physical phenomena are needed to implement continuous monitoring. The first one is the phenomenon of Bloch oscillations. These oscillations, observed in the movement of cooled atoms at temperatures below the photonic recoil limit, placed within a stationary light wave and subjected to an external force, occur at a frequency strictly proportional to the acceleration. (1) The second ingredient is Collective Atomic Recoil Laser (CARL). This effect is observed with cold atoms interacting with two counterpropagating modes of a ring cavity. (2) It is due to the conversion of kinetic energy from atoms used to create a field of laser radiation containing information about atomic motion. The created field serves as a non-destructive and continuous proof of the dynamics of wave-matter and the inertial forces which it is subjected. (3) Optical cooling of strontium is performed in a two-step process. So far, the first phase has been implemented and we are working on the second. In the first phase, strontium $^1 S_0 - ^1P_1$ at 461 nm, with 32 MHz line width. When trap is loaded with sufficient number of atoms, the laser beams of this (blue) MOT are turned off and the second phase starts, which consists of a (red) MOT operated at the narrow $^1 S_0 - ^3P_1$ intercombination line of 7.6 kHz at 689 nm. Temperatures around 1 $\mu$K should be attained. Now, laser beams near the resonance at 689 nm are injected into the two counterpropagating modes of the cavity. They form a standing wave interacting with the atoms. Within this wave the atoms perform Bloch oscillations that can be continuously monitored by beating the light fields leaking from the cavity and superimposed on a photodetector.
Referências
1 FERRARI, G. et al. Long-lived Bloch oscillations with Bosonic Sr atoms and application to gravity measurement at the micrometer scale. Physical Review Letters, v. 97,n. 6, p. 060402-1-060402-4, Aug. 2006.
2 SAMOYLOVA, M. et al. Synchronization of Bloch oscillations by a ring cavity. Optics Express, v. 23, n.11, p. 14823-14835, 2015.
3 SAMOYLOVA, M. et al. Mode-locked Bloch oscillations in a ring cavity. Laser Physics Letters, v. 11, n. 12, p. 126005-1-126005-7, Dec. 2014.
| Subárea | Física Atômica e Molecular |
|---|---|
| Apresentação do trabalho acadêmico para o público geral | Não |
