Dark-state resonances observed on the D2 line of potassium
Authors: Krasteva A., Gateva S., Andreeva C., Alzetta G., Gozzini S., Moi L., Sarkisyan D., Nasyrov K., Cartaleva S.
Autors Affiliation: Institute of Electronics, BAS, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria; Istituto
Nazionale di Ottica del CNR – SS Pisa, Via Moruzzi 1, 56124 Pisa, Italy; Institute for Physical Research, NAS of Armenia, Ashtarak-2, 0203 Armenia; Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia
Abstract: We report the first observation of sub-natural-width dark resonances of enhanced transparency on the D-2 line of potassium, contained in an optical cell with reduced (8mm) dimensions and buffered by 30Torr of Ne. The Potassium vapours are irradiated by a frequency modulated DFB diode laser light (with lambda = 766.7nm and 2MHz bandwidth), and are placed in orthogonal to the light magnetic field scanned around zero value. Very good signal-to-noise ratio and narrow (similar to 20kHz) dark resonances are observed and studied in unshielded laboratory environment. The dark resonance formation is related to coherent superposition of the ground-state Zeeman sublevels by respective components of the frequency-modulated light.
More Information: doi: 10.1117/12.2264223KeyWords: dark state; sub-natural-width optical resonances;