47 research outputs found
Laser locking to the 199Hg clock transition with 5.4x10^(-15)/sqrt(tau) fractional frequency instability
With Hg atoms confined in an optical lattice trap in the Lamb-Dicke regime,
we obtain a spectral line at 265.6 nm in which the full-width at half-maximum
is <15Hz. Here we lock an ultrastable laser to this ultranarrow clock
transition and achieve a fractional frequency stability of
5.4x10^(-15)/sqrt(tau) for tau<=400s. The highly stable laser light used for
the atom probing is derived from a 1062.6 nm fiber laser locked to an
ultrastable optical cavity that exhibits a mean drift rate of -6.0x10^(-17)
s^(-1) (or -16.9 mHz.s^(-1) at 282 THz) over a five month period. A comparison
between two such lasers locked to independent optical cavities shows a flicker
noise limited fractional frequency instability of 4x10^(-16) per cavity