Publication
Lock-in amplified differential phase contrast
Abstract
We introduce a lock-in method to increase the phase contrast in incoherent Differential Phase Contrast (DPC) imaging. The use of a smart pixel detector with in-pixel signal demodulation, paired with synchronized illumination, provides the basis of a bit-efficient approach to DPC. The experiments show an increased sensitivity by a factor of 8, for equivalent standard DPC measurements; single-shot sensitivity of 0.7 mrad at a frame rate of 1400 fps is demonstrated. This new approach may open the way for the use of incoherent phase microscopy in biological applications where extreme phase sensitivity and millisecond response time is required.
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Related concepts (27)
Phase-contrast X-ray imaging
Phase-contrast X-ray imaging or phase-sensitive X-ray imaging is a general term for different technical methods that use information concerning changes in the phase of an X-ray beam that passes through an object in order to create its images. Standard X-ray imaging techniques like radiography or computed tomography (CT) rely on a decrease of the X-ray beam's intensity (attenuation) when traversing the sample, which can be measured directly with the assistance of an X-ray detector.
Phase-contrast imaging
Phase-contrast imaging is a method of that has a range of different applications. It measures differences in the refractive index of different materials to differentiate between structures under analysis. In conventional light microscopy, phase contrast can be employed to distinguish between structures of similar transparency, and to examine crystals on the basis of their double refraction. This has uses in biological, medical and geological science.
Phase-contrast microscopy
NOTOC Phase-contrast microscopy (PCM) is an optical microscopy technique that converts phase shifts in light passing through a transparent specimen to brightness changes in the image. Phase shifts themselves are invisible, but become visible when shown as brightness variations. When light waves travel through a medium other than a vacuum, interaction with the medium causes the wave amplitude and phase to change in a manner dependent on properties of the medium.
Related publications (32)
Lock-in incoherent differential phase contrast imaging
Christophe Moser, Timothé Laforest, Damien Claude-Marie Loterie, Chiara Bonati
We introduce a lock-in method to increase the phase contrast in incoherent differential phase contrast (DPC) imaging. This method improves the phase sensitivity by the analog removal of the background. The use of a smart pixel detector with in-pixel signal ...
CHINESE LASER PRESS2022High sensitivity, incoherent differential imaging
Microscopic visualisation of optically transparent samples has been a topic of interest for several decades. Features such as density or chemical composition can influence the optical phase of transmitted light, and phase contrast can reveal these structur ...
EPFL2022Compact lensless digital holography
Microscopy is of high interest for biology since it allows imaging features that are too small to
be seen with naked eyes. However, cells are mostly transparent to visible and infrared light
which makes it difficult to see with a traditional microscope. To ...
EPFL2018