Optical coherence of Er${}^{3+}$:Y${}_2$O${}_3$ ceramics for telecommunication quantum technologies

Rikuto Fukumori, Yizhong Huang, Jun Yang +2

We report an optical homogeneous linewidth of 580 $\pm$ 20 Hz of Er${}^{3+}$:Y${}_2$O${}_3$ ceramics at millikelvin temperatures, narrowest so far in rare-earth doped ceramics. We show s…