Excited-State Spectroscopy for STIRAP to the Rovibronic Ground State of ²³Na⁴¹K

Ultracold dipolar molecules with strong long-range and anisotropic interactions provide access to exotic many-body physics and quantum information applications. In this poster, we report excited-state spectroscopy aimed at identifying a suitable intermediate state for coherent two-photon transfer of Na⁴¹K Feshbach molecules to the absolute rovibronic ground state X¹Σ⁺(ν=0, J=0). We perform photoassociation spectroscopy to locate vibrational levels in candidate excited-state manifolds and compare the observed spectra with theoretical predictions. We then resolve and analyze the hyperfine structure of a strongly mixed B¹Π - c³Σ⁺ manifold, and identify a specific level within this manifold as a promising candidate for efficient ground-state transfer. Finally, we discuss experimental considerations for optimizing STIRAP and for improving the yield and phase-space density of ground-state molecules.