Microsphere and microcylinder-assisted microscopy(MAM)has grown steadily over the last decade and is still an intensively studied optical far-field imaging technique that promises to overcome the fundamental lateral r...Microsphere and microcylinder-assisted microscopy(MAM)has grown steadily over the last decade and is still an intensively studied optical far-field imaging technique that promises to overcome the fundamental lateral resolution limit of microscopy.However,the physical effects leading to resolution enhancement are still frequently debated.In addition,various configurations of MAM operating in transmission mode as well as reflection mode are examined,and the results are sometimes generalized.We present a rigorous simulation model of MAM and introduce a way to quantify the resolution enhancement.The lateral resolution is compared for microscope arrangements in reflection and transmission modes.Furthermore,we discuss different physical effects with respect to their contribution to resolution enhancement.The results indicate that the effects impacting the resolution in MAM strongly depend on the arrangement of the microscope and the measurement object.As a highlight,we outline that evanescent waves in combination with whispering gallery modes also improve the imaging capabilities,enabling super-resolution under certain circumstances.This result is contrary to the conclusions drawn from previous studies,where phase objects have been analyzed,and thus further emphasizes the complexity of the physical mechanisms underlying MAM.展开更多
We present a unified electromagnetic modeling of coherence scanning interferometry,confocal microscopy,and focus variation microscopy as the most common techniques for surface topography inspection with micro-and nano...We present a unified electromagnetic modeling of coherence scanning interferometry,confocal microscopy,and focus variation microscopy as the most common techniques for surface topography inspection with micro-and nanometer resolution.The model aims at analyzing the instrument response and predicting systematic deviations.Since the main focus lies on the modeling of the microscopes,the light–surface interaction is considered,based on the Kirchhoff approximation extended to vectorial imaging theory.However,it can be replaced by rigorous methods without changing the microscope model.We demonstrate that all of the measuring instruments mentioned above can be modeled using the same theory with some adaption to the respective instrument.For validation,simulated results are confirmed by comparison with measurement results.展开更多
Light microscopes are the most widely used devices in life and material sciences that allow the study of the interaction of light with matter at a resolution better than that of the naked eye.Conventional microscopes ...Light microscopes are the most widely used devices in life and material sciences that allow the study of the interaction of light with matter at a resolution better than that of the naked eye.Conventional microscopes translate the spatial differences in the intensity of the reflected or transmitted light from an object to pixel brightness differences in the digital image.However,a phase microscope converts the spatial differences in the phase of the light from or through an object to differences in pixel brightness.Interference microscopy,a phase-based approach,has found application in various disciplines.While interferometry has brought nanometric axial resolution,the lateral resolution in quantitative phase microscopy(QPM)has still remained limited by diffraction,similar to other traditional microscopy systems.Enhancing the resolution has been the subject of intense investigation since the invention of the microscope in the 17th century.During the past decade,microsphere-assisted microscopy(MAM)has emerged as a simple and effective approach to enhance the resolution in light microscopy.MAM can be integrated with QPM for 3D label-free imaging with enhanced resolution.Here,we review the integration of microspheres with coherence scanning interference and digital holographic microscopies,discussing the associated open questions,challenges,and opportunities.展开更多
To improve the lateral resolution in microscopic imaging,microspheres are placed close to the object’s surface in order to support the imaging process by optical near-field information.Although microsphere-assisted m...To improve the lateral resolution in microscopic imaging,microspheres are placed close to the object’s surface in order to support the imaging process by optical near-field information.Although microsphere-assisted measurements are part of various recent studies,no generally accepted explanation for the effect of microspheres exists.Photonic nanojets,enhancement of the numerical aperture,whispering-gallery modes and evanescent waves are usually named reasons in context with microspheres,though none of these effects is proven to be decisive for the resolution enhancement.We present a simulation model of the complete microscopic imaging process of microsphere-enhanced interference microscopy including a rigorous treatment of the light scattering process at the surface of the specimen.The model consideres objective lenses of high numerical aperture providing 3D conical illumination and imaging.The enhanced resolution and magnification by the microsphere is analyzed with respect to the numerical aperture of the objective lenses.Further,we give a criterion for the achievable resolution and demonstrate that a local enhancement of the numerical aperture is the most likely reason for the resolution enhancement.展开更多
基金supported by the German Research Foundation(DFG)(Grant Nos.LE 992/14-3 and LE 992/15-3).
文摘Microsphere and microcylinder-assisted microscopy(MAM)has grown steadily over the last decade and is still an intensively studied optical far-field imaging technique that promises to overcome the fundamental lateral resolution limit of microscopy.However,the physical effects leading to resolution enhancement are still frequently debated.In addition,various configurations of MAM operating in transmission mode as well as reflection mode are examined,and the results are sometimes generalized.We present a rigorous simulation model of MAM and introduce a way to quantify the resolution enhancement.The lateral resolution is compared for microscope arrangements in reflection and transmission modes.Furthermore,we discuss different physical effects with respect to their contribution to resolution enhancement.The results indicate that the effects impacting the resolution in MAM strongly depend on the arrangement of the microscope and the measurement object.As a highlight,we outline that evanescent waves in combination with whispering gallery modes also improve the imaging capabilities,enabling super-resolution under certain circumstances.This result is contrary to the conclusions drawn from previous studies,where phase objects have been analyzed,and thus further emphasizes the complexity of the physical mechanisms underlying MAM.
基金support of the following research Projects (Nos.GZ:LE 992/14-3 and LE 992/18-1)by the Deutsche Forschungsgemeinschaft and the EMPIR program (project TracOptic,20IND07)co-financed by the European Union’s Horizon 2020 Research and Innovation Program.
文摘We present a unified electromagnetic modeling of coherence scanning interferometry,confocal microscopy,and focus variation microscopy as the most common techniques for surface topography inspection with micro-and nanometer resolution.The model aims at analyzing the instrument response and predicting systematic deviations.Since the main focus lies on the modeling of the microscopes,the light–surface interaction is considered,based on the Kirchhoff approximation extended to vectorial imaging theory.However,it can be replaced by rigorous methods without changing the microscope model.We demonstrate that all of the measuring instruments mentioned above can be modeled using the same theory with some adaption to the respective instrument.For validation,simulated results are confirmed by comparison with measurement results.
文摘Light microscopes are the most widely used devices in life and material sciences that allow the study of the interaction of light with matter at a resolution better than that of the naked eye.Conventional microscopes translate the spatial differences in the intensity of the reflected or transmitted light from an object to pixel brightness differences in the digital image.However,a phase microscope converts the spatial differences in the phase of the light from or through an object to differences in pixel brightness.Interference microscopy,a phase-based approach,has found application in various disciplines.While interferometry has brought nanometric axial resolution,the lateral resolution in quantitative phase microscopy(QPM)has still remained limited by diffraction,similar to other traditional microscopy systems.Enhancing the resolution has been the subject of intense investigation since the invention of the microscope in the 17th century.During the past decade,microsphere-assisted microscopy(MAM)has emerged as a simple and effective approach to enhance the resolution in light microscopy.MAM can be integrated with QPM for 3D label-free imaging with enhanced resolution.Here,we review the integration of microspheres with coherence scanning interference and digital holographic microscopies,discussing the associated open questions,challenges,and opportunities.
基金support of this research work by the DFG(German Research Foundation)[Grant no.LE 992/14-1,LE 992/15-1].
文摘To improve the lateral resolution in microscopic imaging,microspheres are placed close to the object’s surface in order to support the imaging process by optical near-field information.Although microsphere-assisted measurements are part of various recent studies,no generally accepted explanation for the effect of microspheres exists.Photonic nanojets,enhancement of the numerical aperture,whispering-gallery modes and evanescent waves are usually named reasons in context with microspheres,though none of these effects is proven to be decisive for the resolution enhancement.We present a simulation model of the complete microscopic imaging process of microsphere-enhanced interference microscopy including a rigorous treatment of the light scattering process at the surface of the specimen.The model consideres objective lenses of high numerical aperture providing 3D conical illumination and imaging.The enhanced resolution and magnification by the microsphere is analyzed with respect to the numerical aperture of the objective lenses.Further,we give a criterion for the achievable resolution and demonstrate that a local enhancement of the numerical aperture is the most likely reason for the resolution enhancement.
