fulmrzu2

The path to 500 nK

Authors: Jure Brence, Jaka Pišljar, Tadej Mežnaršič
March 2016

Cesium atoms in an atomic beam are slowed and cooled in the Zeeman slower using a counter-propagating, resonant laser beam and a compensating square-root shaped magnetic field. Next, the atoms are trapped and cooled to temperatures as low as µK in a magneto-optical trap, consisting of six intersecting near-resonant beams in a quadrupole field. To prepare for the last phase, a stronger field is used to compress the cloud. Finally, degenerate Raman sideband cooling places the atoms in an optical lattice and a precisely tuned homogeneous magnetic field. This process spin-polarizes the atoms and reaches temperatures around 500 nK. >> more

A timeline of the most important parameters in our sequence.>> more

 

Zeeman shifted modulation transfer spectroscopy in atomic cesium

Authors: Nejc Janša and Pavel Kos
September 2014

Modulation transfer spectroscopy (MTS) is a useful technique for locking a laser to one of the closed cesium D2 transitions. We have focused on the F = 4 → F' = 5 transition as it is used for laser cooling and creating a magneto-optical trap (MOT) when it comes to cesium atoms. Commonly, the frequency is shifted with the help of an acousto-optic modulator (AOM). However, the results of our experiment show that this could also be done with the help of the Zeeman effect. >> more

Left: The modified MTS scheme used for observing the Zeeman effect. A coil surrounding the cesium cell and two λ/4 plates were added. Right: The MTS spectra around the F=4 to F'=5 transition when introducing an external magnetic field. The response varies when different probe beam polarisations are used. >> other polarisations