Frequency metrology of helium around 1083 nm and determination of the nuclear charge radius

P. Cancio Pastor, L. Consolino, G. Giusfredi +4

We measure the absolute frequency of seven out of the nine allowed transitions between the 2${}^3${\it S} and 2${}^3${\it P} hyperfine manifolds in a metastable ${}^3$He beam by using an…