Optical coherence tomography is a non-invasive imaging technique based on the use of light sources exhibiting a low degree of coherence. Low-coherence interferometric microscopes have been successful in producing internal images of thin pieces of biological tissue; typically samples of the order of 1 mm in depth have been imaged, with a resolution of the order of 10 μm in some portions of the s...

Broadband light generation from a single-mode optical fiber was developed for high-resolution optical coherence tomography (OCT). No noise amplification was observed for light broadened by self-phase modulation. The investigation showed that the intensity noise of light broadened by self-phase modulation in a single-mode optical fiber was much lower than that of continuum light from a microstru...

We describe measurement of the degree of coherence induced by a random light source distributed along the longitudinal z axis. If this degree of coherence is measured only between all the in-plane pairs of points placed along the radial lines it is proportional to the Fourier transform of the source's three-dimensional intensity distribution as seen from the paraxial far zone. A reconstruction ...

The synthesis of a multiple-peak spatial degree of coherence is demonstrated. This degree of coherence enables us to scan different sample points on different altitudes simultaneously and thus decreases the acquisition time. The multipeak degree of coherence is also used for imaging through an absorbing layer with different thicknesses or different indices of refraction along the layer. All our...

We propose to use a mask with a nonredundant array (NRA) of multiple apertures to measure spatial coherence in two dimensions. The spatial distribution of the apertures in the mask is made in such a way that we obtain a quasi-uniform sampling in the coherence domain. The spatial coherence is obtained by Fourier transform of the interferogram generated by the mask when it is illuminated by the l...

Not just light waves—free electrons can also transport optical coherence through vacuum.

Many imaging applications require increasingly bright illumination sources, motivating the replacement of conventional thermal light sources with bright light-emitting diodes, superluminescent diodes and lasers. Despite their brightness, lasers and superluminescent diodes are poorly suited for fullfield imaging applications because their high spatial coherence leads to coherent artefacts such a...

This paper reviews the brightness and coherence properties of radiation from storage rings and free electron lasers (FELs). Starting from the statistical optics and using mutual coherence function of the radiation field, we define the transverse and temporal coherence and modes. Spectral brightness can be represented in radiation phase-space via the Wigner function which is the Fourier transfor...