Narrow line cooling and momentum-space crystals

Narrow line laser cooling is advancing the frontier for experiments ranging from studies of fundamental atomic physics to high precision optical frequency standards. In this paper, we present an extensive description of the systems and techniques necessary to realize $689\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ $^{1}S_{0}\text{\ensuremath{-}}^{3}P_{1}$ narrow line cooling of atomic $^{88}\mathrm{Sr}$. Narrow line cooling and trapping dynamics are also studied in detail. By controlling the relative size of the power broadened transition linewidth and the single-photon recoil frequency shift, we show that it is possible to smoothly bridge the gap between semiclassical and quantum mechanical cooling. Novel semiclassical cooling processes, some of which explicitly depend on the relative size of gravity and the radiative force, are also explored. Moreover, for laser frequencies tuned above the atomic resonance, we demonstrate momentum-space crystals containing up to 26 well defined lattice points. Gravitationally assisted cooling is also achieved with blue-detuned light. Theoretically, we find the blue detuned dynamics are universal to Doppler limited systems. This paper offers the most comprehensive study of narrow line laser cooling to date.