An apparatus for imaging a 3D object immersed in a medium of index of refraction nmed with a thickness larger than optical wavelengths in the medium used for the Imaging, comprising:
- a mechanical mechanism to support the 3D object;
- a first optical system disposed to provide a substantially coherent illumination to the 3D object, wherein the illumination is characterized by a plurality of wavelengths λj, j=1, 2, . . . m, with λj+1<λj, wherein the plurality of wavelengths span a wavelength range of Δλ=λ1−λm;
- at each λj the illumination is characterized by a center position, a radius of curvature, an uniform-intensity illumination diameter at a plane of the 3D object, and a wavevector wherein the wavevector is disposed at one of a plurality of incident wavevectors from about 0 to about 2πnmed/λj, with respect to a longitudinal axis of the 3D object and at a plurality of azimuth angles spanning about 0 to 2π;
- a second optical system comprising an optical image recording device and one or more additional optical components characterized by a numerical aperture NA, the second optical system defining an optical axis, wherein the optical recording device is operable to collect at least a portion of the illumination from the first optical system scattered from 3D object, wherein the optical axis of the second optical system is disposed at one of a plurality of angles between 0 and π/2 with respect to the longitudinal axis of the object and at a plurality of azimuthal angles spanning about 0 to 2π, wherein a field-of-view of the second optical system is within a spatial extent of the uniform-intensity illumination provided by the first optical system;
- a third optical system disposed in an optical path of the first optical system to provide interferometric reintroduction of a portion of the coherent illumination at each λj as a reference beam into the second optical system, wherein each of an amplitude, a phase, a radius of curvature, a path length, and an angle of incidence of the reference beam is adjustable such that a reference illumination suitable for interfering with the portion of the illumination scattered by the 3D object and collected by the second optical system is present at an input of the optical image recording device;
- the image recording device wherein each sub-image formed as a result of interference between the illumination that is scattered by the 3D object and the reference beam at each λj is recorded;
- an adjustment mechanism operable to configure the first, the second, and the third optical systems to collect a plurality of sub-images corresponding to the plurality of wavelengths, to a plurality of illumination and additionally to a plurality of regions of an object spatial frequency space;
- and
- a signal-processing device operable to combine the plurality of sub-images into a separate composite image of the 3D object.