Spin polarization of Doppler-broadened atoms by the broadband nanosecond and transform-limited picosecond laser pulses: case study for the muonium

Abstract

We study the spin polarization of Doppler-broadened atoms by broadband nanosecond (ns) pulses, and compare the polarization efficiency with that by the transform-limited picosecond (ps) pulses that have the same spectral bandwidth. Specific calculations are performed for the case of muonium with a set of density matrix equations and with rate equations using the uncoupled basis states. We find that the polarization efficiency with the broadband ns laser pulses is rather good, although it is not as good as that with the transform-limited ps pulses. Our results imply that, depending on the available laser system, we can use either broadband ns or transform-limited ps laser pulses to polarize almost any Doppler-broadened atoms.