Figure 7

Left: Raman spectroscopy. Transition probability as a function of Raman detuning, for a Rabi frequency of \(\Omega = 2\pi \times 25\) kHz. The gaussian fit (solid line) indicates a full width at half maximum (FWHM) of 90 kHz limited by the atomic velocity spread. Inset: Transition probability versus duration showing Rabi oscillations for different Raman light intensities. Right: Raman spectrocopy FWHM of the peak for different Raman Rabi frequencies. Each point was extracted from a resonance peak obtained with a Raman pulse adjusted to half the Rabi period. The width of the peak is Fourier limited for large Rabi frequencies but limited to \( \approx 90\) kHz by velocity spread for lower values. The solid line shows the expected FWHM as the result of numerical integration of the convolution between a gaussian velocity distribution for a temperature \(T=2\) \(\mu \)K and the profile of a square transition pulse.