Fig. 1.

(A) The three-level scheme used for the data analysis. $k_L$ is the absorption and stimulated emission rate, $k_{FL}$ is the spontaneous emission rate, and $k_R$ is the relaxation rate that is measured. The Gaussian profile represents the laser pulse, resonant with state $|1\rangle$ and off-resonant with state $|2\rangle$. (B) Excited states available in LH2, schematically shown together with a measured absorption spectrum. The red peak represents the excitation spectrum at 800 nm; the arrows indicate possible relaxation channels.