| 主权项 |
1. A method for 3D imaging of a scattering sample, in particular for determining the spatial scattering-power distribution—S(x,y,z) of the sample, comprising:
a. splitting laser light having a wavelength that can be selected within a predetermined band width, into a sample and a reference light beam, b. illumining the sample at N different wavelengths λn, n=1, . . . , N, and returning the light scattered in the sample and also the reference light onto a 2D light detector array, c. superposing the scattered sample light with the reference light on the 2D light detector array and recording in each case one hologram for each of the N wavelengths, d. calculating the electric wave field scattered in the sample for each of the N wavelengths in the plane of the 2D light detector array, e. propagating all calculated wave fields in a predetermined reconstruction plane that is aligned perpendicular to the optical axis of the sample light beam, f. calculating the transverse space-frequency spectrum En(kx,ky,kn), with kn=2π/λn of the electric wave field scattered in the sample and propagated in the reconstruction plane for each of the N wavelengths, g. phase matching of the transverse space-frequency spectrum for each of the N wavelengths for compensation of the propagation-time differences produced by d) or e) between the propagated wave field and the reference light, h. calculating the depth-dependent scattering-power spectrum S(kx,ky,z) by one-dimensional Fourier transformation of the space-frequency spectra for each transverse space frequency (kx, ky) along the optical axis of the sample beam, and i. calculating the scattering power S(x,y,z) in at least one layer of the sample in the surroundings of the reconstruction plane, wherein phase matching takes place by multiplying each transverse space-frequency spectrum by a phase factor as a function of kn so that the components En(kx0,ky0,kn) of all N space-frequency spectra in the reconstruction plane assume the same value for a predetermined transverse space frequency (kx0, ky0). |
