We report the observation of microwave-forced evaporative cooling of hydroxyl (OH) molecules loaded from a Stark-decelerated beam into an extremely high-gradient magnetic quadrupole trap. We demonstrate cooling by at least an order of magnitude in temperature and three orders in phase-space density, limited only by the low-temperature sensitivity of our spectroscopic thermometry technique, microwave-depletion pulsed laser induced fluorescence (PLIF). We also present work toward development of a new spectroscopic thermometry technique, optical-depletion PLIF, which should be capable of probing lower temperatures.
View poster as pdf.