Recovering Lost Image Information Through Image-Plane Holographic Microscopy
Researchers at the Center for Extreme Ultraviolet Science and Technology (ERC EUV), an NSF-funded Engineering Research Center headquartered at Colorado State University, have developed a microscopy technique that allows reconstruction of absorption- and phase-contrast images from a weakly absorbing object.
This technique makes it possible to recover important information that would otherwise be lost because phase is not recorded. The result is substantially improved images from objects that have low absorption. These capabilities make it possible to reconstruct the 3D morphology of nanostructures.
Images captured with a conventional microscope are a magnified map of the absorption or reflection contrast in the object. Important information is lost because phase is not recorded, thus making it difficult or impossible to obtain images from objects that have low absorption. Through the use of an imaging geometry that combines a reference wave interfering with the object wave at the image plane, it is possible to capture, with a microscope, broad-area images for which the amplitude and phase image-plane holographic microscopy is particularly attractive. This improvement is made possible when using EUV and soft x-ray illumination that strives for absorption contrast when the wavelength of the illumination is far from specific absorption edges.