Atomic vapor cells for chip-scale atomic clocks with improved long-term frequency stability.
A novel technique for microfabricating alkali atom vapor cells is described in which alkali atoms are evaporated into a micromachined cell cavity through a glass nozzle. A cell of interior volume 1 mm3, containing 87Rb and a buffer gas, was made in this way and integrated into an atomic clock based on coherent population trapping. A fractional frequency instability of 6 x 10(-12) at 1000 s of integration was measured. The long-term drift of the F=1, mF=0-->F=2, mF=0 hyperfine frequency of atoms in these cells is below 5 x 10(-11)/day.
Knappe
S
S
Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 8030, USA. knappe@boulder.nist.gov
Gerginov
V
V
Schwindt
P D D
PD
Shah
V
V
Robinson
H G
HG
Hollberg
L
L
Kitching
J
J