Kramers–Kronig relation in a Doppler-broadened Λ-type three-level system |
(a) Energy level diagram. (b) Experimental setup (DL1 and DL2: diode lasers; AOM: acousto-optic modulator; λ /2: half-wave plate; PZT: mirror mounted on a piezoceramic transducer; BS: 50/50 beam splitter; PBS: polarizing beam splitter; D1, D2, and D3: photo detectors; SG: signal generator; LIA: lock-in amplifier). |