Subkilohertz linewidths measured by heterodyne-detected coherent population trapping in sodium vapor.
Subkilohertz spectroscopy by coherent population trapping (CPT) has been performed in Na atomic vapor. The system employs a frequency-swept acousto-optic modulator for bichromatic excitation as well as a heterodyne-lock-in detection technique that permits the direct measurement of the CPT dispersion curves at a good signal-to-noise ratio. A CPT linewidth of -400 Hz was measured as well as a steep refractive-index dispersion of as much as 3.3 x 10(-10) Hz(-1), corresponding to a group velocity of 1800 m/s.
Motomura
Koji
K
Department of Physics, Faculty of Science, Kumamoto University, 2-39-1 Kurokami, Kumamoto-shi, Kumamoto 860-8555, Japan.
Koshimizu
Takanori
T
Harada
Ken-ichi
K
Ueno
Hirotaka
H
Mitsunaga
Masaharu
M