Laser-induced coherent population trapping in C60

Coherent population trapping (CPT) and electromagnetically induced transparency in atoms have garnered enormous attention because of their conceptual novelty in quantum optics and potential applications in quantum information processing. Here, we show that CPT can occur in buckminsterfullerene C₆₀. If we radiate C₆₀ with a cw coupling field first and then with a weak probe field, C₆₀ becomes much less absorptive. Turning off the coupling field restores the absorptive nature. Using two coupling pulses, we can prepare C₆₀ in a dark state, which is transparent to the probe field. Such a dark state sensitively depends on the laser field amplitude, pulse durations, time delay between two coupling pulses, and laser chirps. Too strong fields refill the ground state, while too long durations overshoot the population and become less effective. There is an optimal delay between two pulses. By employing the first-principles method and solving the Liouville equation dynamically, we scan the vast laser parameter space and find a practical path to coherent population trapping in C₆₀, which is of great importance for future experimental investigations.