Spatial Distribution Of Multi-Photon Absorption Induced Fluorescence Of C₂₂H₂₂N₄O

With the development of high peak power and ultrashort-pulsed lasers, multi-photon techniques have become an important tool for investigation of physical properties of materials. Two-photon absorption induced fluorescence has been used in microscopy, two-photon fluorescence cross-correlation, optical power limiting and optical data storage. Investigation of fluorescence spatial distribution in sample can reveal one-, two-, and three-photon fluorescence characteristics, at the same time is likely to accelerate multi-photon techniques applications.In this paper we compute the experimental date use two-level model and gained one-photon,two-photon and three-photon cross section of C22H22N4O. Based on these results, we can easily write out the spatial distribution of fluorescence. The intensity of the incident pulse depends on space and time. We calculate fluorescence spatial distribution with gauss pluses, which spatial and temporal distribution is a gauss function. Using this theory we carry through the following investigation: Fist count fluorescence spatial distribution under one-photon,two-photon and three-photon excitation of thin sample; Later calculate fluorescence spatial distributions under one-photon,two-photon and three-photon excitation of thick sample; In succession calculate fluorescence spatial distribution in different concentration solution .The concentration of the solution is increasing gradually. With the increasing of the concentration of particles in solution ,the position of the fluorescence intensity point shifts from the geometrical toward the medium surface ,for one-photon,two-photon and three-photon fluorescence the shift speed is decreased sharply ,When the concentration increasing one-photon fluorescence is convergence at the surface quickly, and two-photon fluorescence changed slowly ,three-photon fluorescence changed little; At last compute fluorescence spatial distribution at different corset of the incidence laser. One-photon fluorescence intensity proportion to the incident laser intensity,Two-photon fluorescence intensity proportion to the square of incident laser intensity,Three-photon fluorescence intensity proportion to the...