Characterization and correction of spherical aberration due to glass substrate in the design and fabrication of Fresnel zone lenses
TL;DR: Two novel schemes for correction of spherical aberration are proposed and studied and the accuracy of the proposed aberration correction schemes is validated.
Abstract: As with a conventional lens, a Fresnel zone lens (FZL) can be used to image objects at infinity or nearby In the latter case, the FZL converts a diverging spherical wavefront into a converging spherical wavefront The glass substrate on which the FZL is fabricated introduces spherical aberration resulting in a shift of the image plane and blurring of the image Two novel schemes for correction of this spherical aberration are proposed and studied in this paper To demonstrate them, FZLs are designed with and without aberration correction They are fabricated using electron beam direct writing The devices are evaluated and the accuracy of the proposed aberration correction schemes is validated
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TL;DR: In this paper, a random-like coded phase mask (CPM) is used to modulate light diffracted by a point object (pinhole) and the intensity pattern is recorded and composed as a point spread hologram (PSH).
Abstract: We present a lensless, interferenceless incoherent digital holography technique based on the principle of coded aperture correlation holography. The acquired digital hologram by this technique contains a three-dimensional image of some observed scene. Light diffracted by a point object (pinhole) is modulated using a random-like coded phase mask (CPM) and the intensity pattern is recorded and composed as a point spread hologram (PSH). A library of PSHs is created using the same CPM by moving the pinhole to all possible axial locations. Intensity diffracted through the same CPM from an object placed within the axial limits of the PSH library is recorded by a digital camera. The recorded intensity this time is composed as the object hologram. The image of the object at any axial plane is reconstructed by cross-correlating the object hologram with the corresponding component of the PSH library. The reconstruction noise attached to the image is suppressed by various methods. The reconstruction results of multiplane and thick objects by this technique are compared with regular lens-based imaging.
37 citations
TL;DR: In this paper, the authors used a randomly multiplexed bifocal binary diffractive Fresnel zone lenses fabricated using electron beam lithography for super-resolution 3D imaging.
Abstract: Fresnel incoherent correlation holography (FINCH) is a self-interference based super-resolution three-dimensional imaging technique. FINCH in inline configuration requires an active phase modulator to record at least three phase-shifted camera shots to reconstruct objects without twin image and bias terms. In this study, FINCH is realized using a randomly multiplexed bifocal binary diffractive Fresnel zone lenses fabricated using electron beam lithography. The object space is calibrated by axially scanning a point object along the optical axis and recording the corresponding point spread holograms (PSHs). An object is mounted within the calibrated object space, and the object hologram was recorded under identical experimental conditions used for recording the PSHs. The image of the object at different depths was reconstructed by a cross-correlation between the object hologram and the PSHs. Application potential including bio-medical optics is discussed.
34 citations
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TL;DR: The reconstruction results of multiplane and thick objects by this technique are compared with regular lens-based imaging.
Abstract: We present a lensless, interferenceless incoherent digital holography technique based on the principle of coded aperture correlation holography. The acquired digital hologram by this technique contains a three-dimensional image of some observed scene. Light diffracted by a point object is modulated using a random-like coded phase mask (CPM) and the intensity pattern is recorded and composed as a point spread hologram (PSH). A library of PSH is created using the same CPM by moving the pinhole to all possible axial locations. Intensity diffracted through the same CPM from an object placed within the axial limits of the PSH library is recorded by a digital camera. The recorded intensity this time is composed as the object hologram. The image of the object at any axial plane is reconstructed by cross-correlating the object hologram with the corresponding component of the PSH library. The reconstruction noise attached to the image is suppressed by various methods. The reconstruction results of multi-plane and thick objects by this technique are compared with regular lens-based imaging.
27 citations
TL;DR: This tutorial discusses one of the basic optical configurations of a lensless QPI technique based on the phase-retrieval algorithm andmented codes in Octave for image acquisition and automation using a web camera in an open source operating system are provided.
Abstract: Quantitative phase imaging (QPI) techniques are widely used for the label-free examining of transparent biological samples. QPI techniques can be broadly classified into interference-based and interferenceless methods. The interferometric methods which record the complex amplitude are usually bulky with many optical components and use coherent illumination. The interferenceless approaches which need only the intensity distribution and works using phase retrieval algorithms have gained attention as they require lesser resources, cost, space and can work with incoherent illumination. With rapid developments in computational optical techniques and deep learning, QPI has reached new levels of applications. In this tutorial, we discuss one of the basic optical configurations of a lensless QPI technique based on the phase-retrieval algorithm. Simulative studies on QPI of thin, thick, and greyscale phase objects with assistive pseudo-codes and computational codes in Octave is provided. Binary phase samples with positive and negative resist profiles were fabricated using lithography, and a single plane and two plane phase objects were constructed. Light diffracted from a point object is modulated by phase samples and the corresponding intensity patterns are recorded. The phase retrieval approach is applied for 2D and 3D phase reconstructions. Commented codes in Octave for image acquisition and automation using a web camera in an open source operating system are provided.
18 citations
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TL;DR: In this article, a modified hologram reconstruction mechanism is presented which introduces the single shot capability in Fresnel incoherent correlation holography (FINCH) in inline configuration requires an active phase modulator and at least three camera shots to reconstruct objects without the twin image and bias terms.
Abstract: Fresnel incoherent correlation holography (FINCH) is a self-interference based super-resolution three-dimensional imaging technique. FINCH in inline configuration requires an active phase modulator and at least three camera shots to reconstruct objects without the twin image and bias terms. In this study, FINCH is realized using a randomly multiplexed bifocal binary Fresnel zone lenses fabricated using electron beam lithography. A modified hologram reconstruction mechanism is presented which introduces the single shot capability in FINCH. A point spread hologram library was recorded using a point object located at different axial locations and an object hologram was recorded. The image of the object at different planes were reconstructed using decorrelation of the object hologram by the point spread hologram library. Application potential including bio-medical optics is discussed.
17 citations
Cites background from "Characterization and correction of ..."
...Earlier studies indicated that the exclusion of the thickness and refractive index of glass plates introduces substantial spherical aberration into the system resulting in a variation in the focal distances and blurring of the focal spot.(19) Two techniques have been proposed to avoid the spherical aberration....
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...The second Fresnel zone lens (FZL2) is designed for finite conjugate mode with u = z1 and v = z2/2.(19) The object wave is focused by FZL2 at z2/2 from the RMBDL....
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References
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TL;DR: Theoretical analysis indicates that the optical characteristics of reflection Fresnel lenses can be improved compared with a conventional transmission micro-Fresnel lens and their use in an integrated focus sensor is proposed.
Abstract: Blazed reflection micro-Fresnel lenses and their use in an integrated focus sensor are proposed. Theoretical analysis indicates that the optical characteristics of reflection Fresnel lenses can be improved compared with a conventional transmission micro-Fresnel lens. These reflection Fresnel lenses were fabricated using electron-beam lithography and exhibited the diffraction-limited focusing characteristics with 71% high efficiency. The focus sensor has a folded optical path and includes a beam splitter integrated with thin film components, such as a reflection elliptical Fresnel lens and a quadrant photodetector. The reflection elliptical Fresnel lens in the focus sensor exhibiting excellent astigmatic characteristics agreed with the theoretical results, and the focus error signal was detected. This sensor can be developed as the optical head of an optical disk system.
53 citations
TL;DR: In this paper, a micro-fabricated Fresnel zone plate was used to trap 2μm diameter beads in water with stiffness comparable to conventional optical tweezers.
Abstract: We demonstrate the trapping of beads in water with a microfabricated Fresnel zone plate. Beads are loaded onto the microfabricated optical traps using conventional optical tweezers and fluorescence microscopy is used to track bead position. Analysis of the bead position as a function of time is used to determine trapping stiffness. We present experiments showing the three-dimensional trapping of 2μm diameter beads with trapping stiffnesses that are comparable to conventional optical tweezers when the zone plate efficiency is taken into account.
51 citations
"Characterization and correction of ..." refers background in this paper
...Fresnel zone lenses (FZLs) have been widely used for various applications from focusing x rays to optical trapping [1–7]....
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TL;DR: An arbitrarily shaped lineal Fresnel lens acting either as sole concentration stage or as the first stage of a two-stage concentration system in which the second stage considers the first as a Lambertian source.
Abstract: In this paper we analyze an arbitrarily shaped lineal Fresnel lens acting either as sole concentration stage or as the first stage of a two-stage concentration system in which the second stage considers the first as a Lambertian source. We determine the gain and position of the lens for all possible configurations, and we demonstrate that a curved lens with a refractive-index approaching infinity and with a given profile turns out to be an ideal concentrator.
46 citations
"Characterization and correction of ..." refers background in this paper
...Fresnel zone lenses (FZLs) have been widely used for various applications from focusing x rays to optical trapping [1–7]....
[...]
TL;DR: In this paper, the authors demonstrate the use of adaptive optics to predict and correct these aberrations for both the recording and read-out of optical data storage devices, in order to maintain diffraction-limited operation.
Abstract: The recording of data in multiple layers, rather than a single layer, permits a significant increase in the capacity of optical data storage devices. However, focusing to the different layers introduces different amounts of depth-dependent aberrations. Variable aberration correction is therefore necessary to maintain diffraction-limited operation. We demonstrate the use of adaptive optics to predict and correct these aberrations for both the recording and read-out of such media.
45 citations
"Characterization and correction of ..." refers methods in this paper
...Other aberration–correction methods include the use of deformable mirror membranes [19]....
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TL;DR: Numerical results show that hollow beams can be generated and can also be controlled by the number of the zones and the topological charge, which implies the potential applications of such kind of zone plate in trapping and manipulating particles.
Abstract: Focusing properties of Fresnel zone plates with spiral phase with integer and fractional topological charges illuminated by plane wave are studied. Numerical results show that hollow beams can be generated and can also be controlled by the number of the zones and the topological charge, which implies the potential applications of such kind of zone plate in trapping and manipulating particles.
31 citations