Optical spectroscopy and coherent dynamics of 167Er3＋: YVO4 at 1.5μm below 1 K

In this work the 1.53μm transition of 167Er3+: YVO4 is investigated with high-resolution laser spectroscopy at sub-Kelvin temperatures. At zero field, hyperfine splitting of approximately 2 GHz is observed, and the optical absorption line is divided into three separate bands. With an external magnetic field of 1 T, the phase memory time has reached the superhyperfine limit, corresponding to an effective homogeneous linewidth which is less than 1 kHz. We have also performed spectral hole burning experiments and the ground-state hyperfine lifetime is longer than 15 s. These properties indicate that 167Er3+: YVO4 is a promising candidate material for potential quantum memory applications working at telecom wavelengths.