Director-General Invited Seminar

We are going to hold seminar by Dr. Donggen Luo at Peking University. I'm looking forward to your attendance to the seminar.

Our eyes are extremely sensitive to light. Absorption of only 5-7 photons can trigger light perception in our brain. Indeed, rod photoreceptors, the dim-light sensors in our eyes, have the ability to detect single-photon absorption. In another word, the photoactivation of single visual-pigment molecule (light-sensing molecules in photoreceptors) produces an electrical signal large enough to report to the brain. However, rods also have noise. About once per minute, a rod produces a false signal, equivalent to the absorption of a photon, owing to the spontaneous (thermal) activation of a rod-pigment molecule (rhodopsin). This thermal noise limits our absolute visual threshold by acting as “dark light”.