Search results for "Image formation theory"

showing 2 items of 2 documents

Apertureless scanning near-field optical microscopy: a comparison between homodyne and heterodyne approaches

2006

International audience; In coherent homodyne apertureless scanning near-field optical microscopy (ASNOM) the background field cannot be fully suppressed because of the interference between the different collected fields, making the images difficult to interpret. We show that implementing the heterodyne version of ASNOM allows one to overcome this issue. We present a comparison between homodyne and heterodyne ASNOM through near-field analysis of gold nanowells, integrated waveguides, and a single evanescent wave generated by total internal reflection. The heterodyne approach allows for the control of the interferometric effect with the background light. In particular, the undesirable backgro…

HeterodyneImage formationPhase (waves)Near and far fieldOptical fields02 engineering and technologyInterference (wave propagation)Total internal reflection01 natural sciencesDestructive interference010309 opticsOptics0103 physical sciences[SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/MicroelectronicsPhysicsTotal internal reflectionNear field opticsbusiness.industryTapered fibersNear-field opticsScanning microscopyStatistical and Nonlinear Physics021001 nanoscience & nanotechnologyAtomic and Molecular Physics and OpticsInterferometryImage formation theory[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic0210 nano-technologybusinessScanning electron microscopy
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Left-handed metamaterial coatings for subwavelength-resolution imaging

2012

We report on a procedure to improve the resolution of far-field imaging by using a neighboring high-index medium that is coated with a left-handed metamaterial. The resulting plot can also exhibit an enhanced transmission by considering proper conditions to retract backscattering. Based on negative refraction, geometrical aberrations are considered in detail since they may cause a great impact in this sort of diffraction-unlimited imaging by reducing its resolution power. We employ a standard aberration analysis to refine the asymmetric configuration of metamaterial superlenses. We demonstrate that low-order centrosymmetric aberrations can be fully corrected for a given object plane. For su…

Point spread functionPhysicsbusiness.industryPlane (geometry)Resolution (electron density)MetamaterialPhysics::OpticsImage planeAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsOpticsTransmission (telecommunications)Negative refractionImage formation theoryMetamaterialsComputer Vision and Pattern RecognitionTransmission coefficientbusinessAberration compensationÓptica
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