The optical characteristics of Diffractive Optical Elements are determined by the properties of the photosensitive
film on which they are produced. When working with photoresist plates, the most important property is the
change in the plate's topography for different exposures. In this case, the required characterization involves a
topographic measurement that can be made using digital holography. This work presents a digital holography
system in which a hologram's phase map is obtained from a single recorded image. The phase map is calculated
by applying a phase-shifting algorithm to a set of images that are created using a digital phase-shifting/tilteliminating
procedure. Also, the curvatures, introduced by the imaging elements used in the experimental setup,
are digitally compensated for using a polynomial fitting-method. The object's topography is then obtained from
this modified phase map. To demonstrate the proposed procedure, the topography of patches exposed on a
Shipley 1818 photoresist plate by microlithography equipment-which is currently under construction-is shown.
Spatial filtering techniques are used in the analysis of interferograms and off-axis digital holograms to obtain the
phase information from an optical field. The masks applied for the selection of the virtual image order in the
frequency space usually have regular shapes and are located by hand. Therefore, they create artifacts that hide
some details in the obtained phase, especially when holograms from objects with sharp edges are reconstructed.
In this work, a novel algorithm that automatically calculates and locates the mask separating the spectral orders
is presented. This new method uses a distance criterion between the maximum values in the amplitude spectrum
as a clustering parameter. The values for the distance parameter are changed and the results are analyzed for a
simulated image-plane hologram. As an example of the algorithm application, a digital hologram obtained from
one USAF-1951 test target is reconstructed and the phase of the test target element is obtained.