Hybrid atom-membrane optomechanics

5 05/2014

Monday, 05 May. 2014, 15:30 - 16:30

Presenter: Philipp Treutlein
Host: Nikolai Kiesel
Where: Lise-Meitner-Hörsaal, 1. Stock, Strudelhofgasse 4, Wien


Hybrid atom-membrane optomechanics


In optomechanics, laser light is used for cooling and control of the vibrations of micromechanical oscillators, with many similarities to the cooling and trapping of atoms. It has been proposed that laser light could also be used to couple the motion of ultracold atoms in a trap to the vibrations of a mechanical oscillator. In the resulting hybrid system the atoms could be used to read out the oscillator, to sympathetically cool it, and ultimately to create atom-oscillator entanglement.


We have realized a hybrid system in which ultracold atoms and a micromechanical membrane are coupled by radiation pressure forces. The atoms are trapped in an optical lattice, formed by retro-reflection of a laser beam from an optical cavity that contains the membrane as mechanical element. When we laser cool the atoms, we observe that the membrane is sympathetically cooled from ambient to millikelvin temperatures through its interaction with the atoms. Sympathetic cooling with ultracold atoms or ions has previously been used to cool other microscopic systems such as atoms of a different species or molecular ions up to the size of proteins.

Here we use it to efficiently cool the fundamental vibrational mode of a macroscopic solid-state system, whose mass exceeds that of the entire atomic ensemble by eight orders of magnitude. Our hybrid system operates

in a regime of large atom-membrane cooperativity, enabling studies of phenomena like electromagnetically induced transparency. With cryogenic pre-cooling of the membrane, ground-state cooling and strong coupling on the single-phonon level are within reach.