Electromagnetically Induced Trasparency on the first and second Resonance lines of Potassium

Coherent Population Trapping (CPT) is observed on the first and second resonance lines of potassium, by irradiating the vapor by 770.1 nm and 404.5 nm diode laser light, respectively. With the 770.1 nm excitation, narrow CPT resonance is observed demonstrating 80 times larger contrast than in case of Cs vapor, in coated optical cell. A theoretical model is proposed to explain strong resonance contrast enhancement. Irradiating K vapor with the 404.5 nm laser, the CPT resonance is observed both on the 404.5 nm and 770.1 nm lines, which makes the study of various cascade transitions in potassium possible.