Pump--probe fluorescence microscopy has been demonstrated to be a powerful tool for obtaining three-dimensional, time-resolved information in bioimaging applications. However, the use of this technique can be complicated by the fact that the different wavelengths used to achieve pump--probe microscopy can result in wavelength-dependent spherical aberration, thus limiting the usefulness of the technique. We address this issue by investigating the effects of refractive-index-mismatch-induced spherical aberration on pump--probe image formation. We model the effects by considering pump--probe imaging performed with an objective with a numerical aperture of 0.75 focusing through an oil-water interface. Our results show that spherical aberration has the greatest effect in degrading an axial point-spread function. In addition to signal loss, the redistribution of signal strength along the axial direction results in broadening of the FWHM of the plane response function. The inclusion of confocal detection tends to improve image resolution but at a significant loss of signal strength.
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http://dx.doi.org/10.1364/ao.44.004220 | DOI Listing |
Int Ophthalmol
January 2025
Department of Ophthalmology, Peking University Third Hospital, No 49 Huayuan North Road, Haidian District, Beijing, 100191, China.
Purpose: To evaluate clinical outcomes and visual quality 12 months after small incision lenticule extraction (SMILE) for correction of myopia with or without astigmatism in patients during the incipient phase of presbyopia.
Setting: Peking University Third Hospital, Beijing, China.
Design: Retrospective observation study.
Optom Vis Sci
January 2025
School of Optometry, Indiana University, Bloomington, Indiana.
Significance: Visual acuity (VA) depends on many factors. When the goal is to assess retinal health rather than performance, then using a 3-mm pupil reduces unwanted wavefront aberrations. The axis of astigmatism can still potentially change with age.
View Article and Find Full Text PDFWe theoretically demonstrate that ponderomotive interactions near the electron cross-over can be used for aberration correction in ultrafast electron microscopes. Highly magnified electron shadow images from SiN thin films are utilized to visualize the distortions induced by spherical aberrations. Our simulations of electron-light interactions indicate that spherical aberrations can be compensated resulting in an aberration-free angle of 8.
View Article and Find Full Text PDFSpecimen-induced aberrations limit the penetration depth of standard optical imaging techniques in vivo, mainly due to the propagation of high NA beams in a non-homogenous medium. Overcoming these limitations requires complex optical imaging systems and techniques. Implantable high NA micro-optics can be a solution to tissue induced spherical aberrations, but in order to be implanted, they need to have reduced complexity, offering a lower surface to the host immune reaction.
View Article and Find Full Text PDFIn the last few years, new ways of structuring light have emerged, with the potential to be used in a wide variety of applications, including materials processing, micro-particle manipulation and charged particle acceleration. One of these techniques is the structured laser beam (SLB). The important advantages of this beam are the simple generation principle using spherical aberration and the potentially infinite propagation range.
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