Coherent Ptychographic Imaging Microscope With 17.5nm Spatial Resolution Employing 13.5nm High Harmonic Light
In this work, a tabletop transmission-mode ptychographic microscope which uses coherent 13.5 nm Extreme Ultraviolet light is demonstrated. An image of a fresnel zone plate taken using this microscope is presented and compared to one taken with a scanning electron microscope. The new ptychographic microscope has a numerical aperture of .4 and demonstrates 17.5nm resolution. The source is an actively-stabilized 20fs, 2mJ, 3kHz, Ti:Sapphire laser with 785nm center wavelength focused into a 150um Helium-filled hollow-core optical fiber. The harmonics are focused using an off-axis spherical mirror.