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(-1), compressing its velocity spread by a factor of 10 while retaining high intensity: at a velocity of 15 m s(-1) the flux, measured 1.3. m from the source, is 7 x 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.