Patent ID: 8441633

Claim:
A multi-photon excitation light sheet microscope comprising: a sample holder; at least one excitation source, said excitation source being capable of producing an excitation beam having a power of adequate intensity to induce significant levels of multi-photon excitation in a sample, and being disposed such that the excitation beam is directed along at least one excitation beam path, wherein the at least one excitation beam path is provided with an excitation focusing optics for producing a substantially two-dimensional multi-photon excitation light sheet that defines a sample excitation region which extends along the excitation beam path and transversely thereto and intersects with at least a portion of the sample holder; an imaging detector defining at least one detection beam path and capable of detecting an excitation generated signal contrast from the sample excitation region, the detector being disposed such that the detection direction of the at least one detection beam path is substantially orthogonal to the direction of the excitation beam path; and wherein the multi-photon excitation light sheet is comprised of photons that each have an energy such that the sum of the energy of at least two of said photons is sufficient to cause multi-photon excitation and thereby excite a signal contrast in said sample excitation region, and wherein said signal contrast is proportional to I n , where I is the instantaneous intensity of the excitation energy at the sample excitation region and n is the number of said at least two photons that cause multi-photon excitation.