Ultrashort pulse two-photon coherent control of a macroscopic phenomena: light-induced current from channelrhodopsin-2 in live brain cells

Coherent control is extended to macroscopic processes under continuous pulsed laser irradiation. Here, this approach is used to analyze the experimentally measured two-photon phase control of currents emanating from a living brain cells expressing channelrhodopsin-2, a light-gated ion channel. In particular, a mechanism is proposed that encompasses more than 15 orders magnitude in time, from the ultrafast dynamics of retinal in channelrhodopsin-2 to the slow dynamics of the neuron current. Implications for other photochemical processes are discussed.