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Coherent diffractive imaging of objects is made considerably more practicable by using ptychography, where a set of diffraction patterns replaces a single measurement and introduces a high degree of redundancy into the recorded data. Here we demonstrate that this redundancy allows diffraction patterns to be extrapolated beyond the aperture of the recording(More)
Quantitative phase microscopy offers a range of benefits over conventional phase-contrast techniques. For example, changes in refractive index and specimen thickness can be extrapolated and images can be refocused subsequent to their recording. In this Letter, we detail a lensless, quantitative phase microscope with a wide field of view and a useful(More)
Ptychography offers the possibility of improving the resolution of atomic-scale (electron and X-ray) transmission microscopy without any of the demands of high quality lenses: its resolution is in theory only limited by the effective synthetic numerical aperture determined by the angular size of the detector. However, it has been realised experimentally(More)
The response of a C60 molecule to manipulation across a surface displays a long range periodicity which corresponds to a rolling motion. A period of three or four lattice constants is observed and is accompanied by complex subharmonic structure due to molecular hops through a regular, repeating sequence of adsorption states. Combining experimental data and(More)
Generally, methods of three-dimensional imaging such as confocal microscopy and computed tomography rely on two essentials: multiple measurements (at a range of focus positions or rotations) and a weakly scattering specimen (to avoid distortion of the focal spot in the confocal microscope or to satisfy the projection approximation in tomography). Here we(More)
This paper shows that visible-light ptychography can be used to distinguish quantitatively between healthy and tumorous unstained cells. Advantages of ptychography in comparison to conventional phase-sensitive imaging techniques are highlighted. A novel procedure to automatically refocus ptychographic reconstructions is also presented, which improves(More)
Ptychography is a coherent imaging technique that enables an image of a specimen to be generated from a set of diffraction patterns. One limitation of the technique is the assumption of a multiplicative interaction between the illuminating coherent beam and the specimen, which restricts ptychography to samples no thicker than a few tens of micrometers in(More)
We have investigated the coadsorption of perylene tetracarboxylic dianhydride (PTCDA) and tetraaminobenzene (TAB) on the Ag/Si(111)-square root(3) x square root(3) R30 degree surface using scanning tunneling microscopy. At room temperature, PTCDA islands with square and herringbone ordering are formed which, on exposure to TAB, are converted into an(More)
As it passes through a sample, an electron beam scatters, producing an exit wavefront rich in information. A range of material properties, from electric and magnetic field strengths to specimen thickness, strain maps and mean inner potentials, can be extrapolated from its phase and mapped at the nanoscale. Unfortunately, the phase signal is not(More)