Laser slowing towards a 3D MOT of CaOH molecules

Polyatomic molecules represent a new frontier in AMO physics, promising a number of new scientific opportunities in areas ranging from quantum simulation to ultracold chemistry to precision measurement. Laser cooling techniques have successfully brought several species of diatomic molecules to ultracold temperatures in the past several years, and have recently been extended to the polyatomic molecules SrOH, YbOH, CaOH, and CaOCH₃. Despite this success, in all cases to date laser cooling was performed in one dimension, which required scattering fewer than 1000 photons. The next step in our path towards laser-cooled, ultracold polyatomic molecules is to capture them in a 3D magneto-optical trap (MOT). Here, we report on progress towards this goal with CaOH. A laser cooling scheme capable of scattering more than 10,000 photons is identified and tested, enabling us to demonstrate radiative slowing to near the MOT capture velocity.