An intense, cold, velocity-controlled molecular beam by   frequency-chirped laser slowing
  Using frequency-chirped radiation pressure slowing, we precisely control the velocity of a pulsed CaF molecular beam down to a few m/s, compressing its velocity spread by a factor of 10 while retaining high intensity: at a velocity of 15~m/s the flux, measured 1.3~m from the source, is 7$\times$10$^{5}$ molecules per cm$^{2}$ per shot in a single rovibrational state. The beam is suitable for loading a magneto-optical trap or, when combined with transverse laser cooling, improving the precision of spectroscopic measurements that test fundamental physics. We compare the frequency-chirped slowing method with the more commonly used frequency-broadened slowing method. 
S. Truppe, H. J. Williams, N. J. Fitch, M. Hambach, T. E. Wall, E. A.   Hinds, B. E. Sauer, M. R. Tarbutt
physics.atom-ph