Patent ID: 7019309

Claim:
A two-photon fluorescence endoscope comprising: (a) an ultrashort pulsed laser source of coherent light suitable to initiate two-photon fluorescence in a sample of interest located at a sample region; (b) a first single mode fiber optic light conductor positioned to receive at its terminal light from said light source and direct said light to a three-port single mode fiber coupler; (c) a second single mode fiber optic light conductor having at its sample end a scanning head comprising a gradient index lens located to receive light from said sample end, and an optical prism which directs light from said gradient index lens transverse to axis of said gradient index lens, the second conductor located to receive light introduced to said coupler from said first conductor and direct said light to said sample via said sample end, said sample end also located to receive fluoresced light from said sample that is collected by said optical prism, passes through said index gradient lens and is thereby directed to said sample end such that said second conductor may direct said fluoresced light to said coupler; (d) a third single mode fiber optic light conductor located to direct fluoresced light from said coupler to a light detection device via a terminal of said third light conductor.