Multiple photon echoes in molecular iodine

Abstract

Backward multiple photon echoes have been realized in the X 1Σ + g-B 3Π + ou transition of molecular iodine. The first and second excitation pulses were the second harmonic pulse trains of an actively mode-locked and Q-switched YAG laser, and the third excitation pulse was a single pulse from a nitrogen-laser pumped dye laser. After the third pulse multiple photon echo pulses were emitted in the opposite direction to the second excitation pulse train. The modulation on the envelope of the multiple photon echoes was explained as the quantum beats originated from the hyperfine splittings of the echo levels.