title: Adaptive optics in multiphoton microscopy: comparison of two, three and four photon fluorescence.
abstract: We demonstrate adaptive optics system based on nonlinear feedback from 3- and 4-photon fluorescence. The system is based on femtosecond pulses created by soliton self-frequency shift of a 1550-nm fiber-based femtosecond laser together with micro-electro-mechanical system (MEMS) phase spatial light modulator (SLM). We perturb the 1020-segment SLM using an orthogonal Walsh sequence basis set with a modified version of three-point phase shifting interferometry. We show the improvement after aberrations correction in 3-photon signal from fluorescent beads. In addition, we compare the improvement obtained in the same adaptive optical system for 2-, 3- and 4-photon fluorescence using dye pool. We show that signal improvement resulting from aberration correction grows exponentially as a function of the order of nonlinearity.
authors.forename: David
authors.initials: D
authors.lastname: Sinefeld
authors.forename: Hari P
authors.initials: HP
authors.lastname: Paudel
authors.forename: Dimitre G
authors.initials: DG
authors.lastname: Ouzounov
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Bifano
authors.forename: Chris
authors.initials: C
authors.lastname: Xu
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005246:Feedback; D005336:Fiber Optic Technology / Q000295:instrumentation*; D007089:Image Enhancement / Q000295:instrumentation*; D007368:Interferometry / Q000295:instrumentation*; D007834:Lasers; D007909:Lenses; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation*; D008904:Miniaturization; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity