A two-mode-laser as an excellent simple tool for exciting sodium atoms from both groundstate levels simultaneously

Na-beam cooling by a mode-locked laser

“…This spectrum has not been broad enough to cover all Doppler shifted frequencies corresponding to the velocity distribution of the Na beam. One mode of the MLL has been stabilized by lock-in technique onto the transmission maximum of a FPI [4] which on the other hand has been stabilized on the Na resonance ( + 50 MHz adjustable) by a method using a difference photodiode [11,12,9]. If the maximum of the MLL spectrum is tuned to a resonance appropriate to an atomic velocity of 300 m/s the FWHM of the 800 MHz spectrum corresponds to velocities from 60 m/s to 540 m/s.…”

“…In this paper we report on the successful experimental realization of Hoffnagle's proposal by using a broadband MLL and a two-mode laser (2ML) which is less expensive and easier to handle than a SML and has been proved to be an excellent tool for exciting Na atoms from both groundstate levels simultaneously [9]. The effectiveness of cooling and the attainable densities of slow atoms are investigated in dependence on different laser parameters.…”

Cooling and polarization of a sodium atomic beam by a two mode laser

“…3 the absorption signals are shown without (a) and with (b) optical pumping. P can be determined for high degrees of atomic polarization to a good approximation directly from the peak intensities in the same manner as has been shown for the Dl-line [3]. Then all population densities except D21, P22 and Pll may be left out so that the mathematical calculation is rather simple (Fig.…”

“…Therefore a laser detuning of -10 MHz relative to the 32S1/2, F= 2--*3 2p3/z, F'= 3 transition is sufficient to excite all Na atoms in the beam. A two mode laser (TML, mode splitting 1712MHz) [3] in resonance with the transitions F=I-*F'=2 and F=2--*F'= 3 of the Na D2-1ine is used to ensure simultaneous excitation from both hyperfine ground states thus maintaining a cyclic absorption and reemission process of the atoms. By this simple excitation technique we do not lose any laser power into other side modes contrary to the most employed electro-optical modulation technique, which in addition is experimentally more expensive.…”

“…By this simple excitation technique we do not lose any laser power into other side modes contrary to the most employed electro-optical modulation technique, which in addition is experimentally more expensive. Our laser is stabilized by means of a two control loop technique [3]. A differentially operating double photodiode keeps the frequency difference to the Na resonance line constant [4].…”