Frequency axis calibration and the state of affairs in Team Strontium

James Millen

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Strontium dispenser cell

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Absorption spectra

• Doppler broadened absorption profile with large FWHM of ~280MHz (?)

• Sloping background due to laser scan

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Saturated absorption spectroscopy

• An intense “pump” laser depopulates the ground state for a narrow velocity class around the central frequency, limited by the width of the transition (32MHz)

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Fitting and calibration

• The saturated absorption feature is Lorentzian in form.

• Fit with a sum of six Lorentzians, one for each isotope (and hyperfine component) of strontium.

• We have five free parameters.

• Use the minimisation function “fminsearch” in MatLab to fit to the data

• Requires a starting set of parameters, the choice of these is not obvious.

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Further spectroscopy in the cell

• Clementine has been doing FM spectroscopy, sub-Doppler DAVLL and strong field polarisation spectroscopy (Hughes spec)

Cell

Beam

Mach

ine

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Aside- The ultra cold strontium experiment

• Vacuum system is fully assembled in new lab (room 34)

• System is aligned

Frequency axis calibration and the state of affairs in Team Strontium – Group meeting 28/07/08

Aside- The ultra cold strontium experiment

• Strontium is loaded into the oven, and the oven is insulated

• The oven section is currently being baked and pumped