We demonstrate background-free imaging and sideband cooling of a single ${}^{133}\mathrm{Cs}$ atom via the narrow-line $6S_{1/2}\to 5D_{5/2}$ electric quadrupole transition in a 1064 nm optical tweezer. The $5D_{5/2}$ state decays through the $6P_{3/2}$ state to the ground state, emitting an 852 nm wavelength photon that allows for background-free imaging. By encoding both spin and orbital angular momentum onto the 685 nm excitation light, we achieve background-free fluorescence histograms with 99.58(3)% imaging fidelity by positioning the atom at the dark center of a vortex beam. Tuning the tweezer polarization ellipticity realizes a magic trap for the stretched $|F=4,m_F=4\rangle \to |F^{\prime }=6,m_F^{\prime }=6\rangle$ cycling transition. Using a Gaussian beam, we cool to $5\mu \mathrm{K}$ in a 1.1 mK trap and outline a strategy for ground-state cooling. We compare cooling performance across different sideband regimes, while also exploring how the orbital angular momentum of structured light controls the selection rules for quadrupole transitions. These results expand the toolbox for high-fidelity quantum control and cooling in alkali-atom tweezer arrays.

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• Angular momentum of light
• Atomic spectra
• Cooling & trapping
• Electronic transitions
• Fine & hyperfine structure
• Structured light