# Radiation Pressure Force from Optical Cycling on a Polyatomic Molecule

#### Abstract

We demonstrate multiple photon cycling and radiative force deflection on the triatomic free radical strontium monohydroxide (SrOH). Optical cycling is achieved on SrOH in a cryogenic buffer-gas beam by employing the rotationally closed $P(N” = 1)$ branch of the vibronic transition ${\tilde{X}}^{2}{{\rm{\Sigma }}}^{+}(000)\leftrightarrow {\tilde{A}}^{2}{{\rm{\Pi_{1 / 2} }}} (000)$. A single repumping laser excites the Sr–O stretching vibrational mode, and photon cycling of the molecule deflects the SrOH beam by an angle of $0.2^\circ$ via scattering of $\sim 100$ photons per molecule. This approach can be used for direct laser cooling of SrOH and more complex, isoelectronic species.

Journal
Journal of Physics B: Atomic, Molecular and Optical Physics 49, 134002 (2016)