Fig. 1: Molecular crystal and optical properties.
From: Optically detected nuclear magnetic resonance of coherent spins in a molecular complex
a, Molecular structure of the complex and crystal unit cell obtained from single-crystal X-ray diffraction. Blue, europium; red, oxygen; black, carbon; cyan, nitrogen; hydrogen is omitted for clarity. Single crystals with ~1-mm size and clear facets were grown. b, Ground- and excited-state hyperfine levels of the 7F0 → 5D0 transition of 151Eu3+. c, Photoluminescence excitation measurement of the 7F0 → 5D0 transition showing a narrow inhomogeneous linewidth of 1.94(1) GHz. FWHM, full-width at half-maximum. d, Optical FID of the optical transition dipoles of ions. Coherent oscillations can be observed as a beating signal via heterodyne detection with a frequency-detuned optical read-out pulse. A fit to the signal yields a pure dephasing time of \({T}_{2,{\rm{o}}({\rm{FID}})}^{* }=\) 770(20) ns.
