An extension of Nomarski differential interference contrast microscopy enables isotropic linear phase imaging through the combination of phase shifting, two directions of shear, and Fourier space integration using a modified spiral phase transform. We apply this method to simulated and experimentally acquired images of partially absorptive test objects. A direct comparison of the computationally determined phase to the true object phase demonstrates the capabilities of the method. Simulation results predict and confirm results obtained from experimentally acquired images.
Quantitative structured-illumination phase microscopy (QSIP) uses a conventional bright field microscope to
quantitatively measure the optical path length profiles of homogenous phase-only objects. The illumination in QSIP is
structured with a predetermined pattern by placing an amplitude mask in the field diaphragm of the microscope. From
the image of the amplitude mask, a numerical algorithm implementing a closed form analytical solution calculates the
object's optical path length profile. In this paper, we investigate the accuracy of the numerical algorithm used and show
that it can be made arbitrarily accurate by using numerical optimization. We then analyze the effect of the system's
numerical aperture (NA), and show that QSIP can be used with a wide range of NAs for objects with small phase
gradients, and can be used with relatively lower NAs for objects with large phase gradients.
Phase-shifting differential interference contrast (DIC) provides images in which the intensity of DIC is transformed into
values linearly proportional to differential phase delay. Linear regression analysis of the Fourier space, spiral phase,
integration technique shows these values can be integrated and calibrated to provide accurate phase measurements of
objects embedded in optically transparent media regardless of symmetry or absorption properties. This approach has the
potential to overcome the limitations of profilometery, which cannot access embedded objects, and extend the
capabilities of the traditional DIC microscope, which images embedded phase objects, but does not provide quantitative
We present a simple setup for obtaining high resolution, sub-micron images using high harmonic generation (HHG) in a hollow-core waveguide as a light source. We demonstrate imaging with illumination at a wavelength of 30 nm using an all-reflective, double-multilayer mirror setup and a CCD camera as a recording device. For the magnifications of up to 50x used here, the all-reflective setup has advantages over zone plate microscopes because of the much larger working distances that allow for imaging of plasmas. This setup has also a throughput that is higher by at least a factor of three compared to zone-plate microscopes, and presents the additional advantage of preserving the temporal pulse width of the harmonics because diffractive optics are not used. This work demonstrates the feasibility of high-spatial-resolution, time-resolved, EUV imaging of plasmas and other objects using a tabletop compact light source.