BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Frequency stabilization of a titanium-sapphire laser and improveme
 nt of qubits based on Ca+-ions - Tobias Macha (University of Mainz)
DTSTART:20130411T090000Z
DTEND:20130411T103000Z
UID:TALK44576@talks.cam.ac.uk
CONTACT:6270
DESCRIPTION:We trap ions in a linear micro segmented Paul-trap for the pur
 pose of\nquantum information processing. Qubits are encoded in magnetic su
 blevels of\nthe ground state of Ca+ and manipulated with laser light near 
 729 nm from a\nTiSa laser. A stable light source is essential to achieve l
 ong coherence\ntimes\, which are necessary for storing quantum information
  in a qubit. The\nfrequency stabilization is performed by locking the lase
 r to an ultra-stable\nFabry-Pérot resonator using a Pound-Drever-Hall err
 or signal and fast\nelectronics. The quality of the lock can be determined
  from a beat note with\nanother laser at 729 nm. Additionally\, a spin-ech
 o sequence on the calcium\nion allows to achieve a value of the laser line
 width and the resulting qubit\ncoherence time. We have separated the contr
 ibution of the magnetic field\nfluctuations on the coherence time by inter
 rogating transitions with\ndifferent susceptibility to the ambient magneti
 c field. A possibility of\nextending the coherence time is demonstrated us
 ing a spin-lock technique
LOCATION:Rutherford building\, Seminar Room B
END:VEVENT
END:VCALENDAR