Cavity ring-down observation of Yb3+ optical absorption in room temperature solution

Cavity ring-down spectroscopy is used to probe the optical absorption of the optical pseudo-two level system [Xe]4f13 Yb3+ in room temperature solution, a situation where the two-color pump-probe luminescence approach commonly used to study the other [Xe]4fn (2 ≤ n ≤ 12) trivalent lanthanide ions fails. A 1 m optical cavity constructed from two highly reflective mirrors is used to obtain ring-down signals as a function of wavelength from 1 mL samples contained in a quartz cuvette placed in the center of the cavity. Absorption spectra constructed from these signals characteristic of the 6H15/2 → 4F9/2 [Xe]4f5 Dy3+ and the 7F0 → 5D0 [Xe]4f6 Eu3+ transitions are presented and compared to the corresponding single pass absorption and two-color pump-probe luminescence spectra to obtain sensitivity estimates. Finally the spectrum for the 2F5/2 → 2F7/2 [Xe]4f13 Yb3+ transition for a model Yb3+ complex in room temperature solution is obtained using cavity ring-down spectroscopy for the first time.