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Journal ArticleDOI

Characterization and correction of spherical aberration due to glass substrate in the design and fabrication of Fresnel zone lenses

20 Aug 2013-Applied Optics (Appl Opt)-Vol. 52, Iss: 24, pp 5932-5940
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
Citations
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Journal ArticleDOI
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

Journal ArticleDOI
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

Posted Content
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

Journal ArticleDOI
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

Posted Content
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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Journal ArticleDOI
TL;DR: The focused ion beam field has been spurred by the invention of the liquid metal ion source and by the utilization of focusing columns with mass separation capability, which has led to the use of alloy ion sources making available a large menu of ion species, in particular the dopants of Si and GaAs as discussed by the authors.
Abstract: Ions of kiloelectron volt energies incident on a solid surface produce a number of effects: several atoms are sputtered off, several electrons are emitted, chemical reactions may be induced, atoms are displaced from their equilibrium positions, and ions implant themselves in the solid, altering its properties. Some of these effects, such as sputtering and implantation are widely used in semiconductor device fabrication and in other fields. Thus the capability to focus a beam of ions to submicrometer dimensions, i.e., dimensions compatible with the most demanding fabrication procedures, is an important development. The focused ion beam field has been spurred by the invention of the liquid metal ion source and by the utilization of focusing columns with mass separation capability. This has led to the use of alloy ion sources making available a large menu of ion species, in particular the dopants of Si and GaAs. The ability to sputter and to also induce deposition by causing breakdown of an adsorbed film has produced an immediate application of focused ion beams to photomask repair. The total number of focused ion beamfabrication systems in use worldwide is about 35, about 25 of them in Japan. In addition, there are many more simpler focused ion beam columns for specialized uses. The interest is growing rapidly. The following range of specifications of these systems has been reported: accelerating potential 3 to 200 kV, ion current density in focal spot up to 10 A/cm2, beam diameters from 0.05 to 1 μm, deflection accuracy of the beam over the surface ±0.1 μm, and ion species available Ga, Au, Si, Be, B, As, P, etc. Some of the applications which have been demonstrated or suggested include: mask repair, lithography (to replace electron beamlithography), direct, patterned, implantationdoping of semiconductors, ion induced deposition for circuit repair or rewiring, scanning ion microscopy, and scanning ion mass spectroscopy.

559 citations


"Characterization and correction of ..." refers methods in this paper

  • ...FZLs can be fabricated by different techniques, such as photolithography [12], electron beam direct writing [15], and focused ion beammilling [22]....

    [...]

Journal ArticleDOI
TL;DR: A blazing technique using electron-beam lithography to achieve higher efficiency of gratings and Fresnel lenses is described, and the experimental results showed high-efficiency performance and nearly diffraction-limited focusing.
Abstract: A blazing technique using electron-beam lithography to achieve higher efficiency of gratings and Fresnel lenses is described. Transmission-type blazed gratings have been formed in polymethyl methacrylate films. As a result of measurement, we found that their diffraction efficiency of the first order in these gratings amounts to as much as 60 to 70% at 0.633 microm. Fresnel lenses of 1-mm diameter and 5-mm focal length, which have a sawtooth relief profile, have been also fabricated, and the experimental results showed high-efficiency performance (about 50%) and nearly diffraction-limited focusing.

166 citations


"Characterization and correction of ..." refers methods in this paper

  • ...In most of the earlier reported situations, the FZLs were designed for converting a plane wavefront into a converging spherical wavefront (f configuration) [8–12]....

    [...]

Journal ArticleDOI
TL;DR: In this article, a new Fresnel zone plate was constructed which can focus ultraviolet radiation of any wavelength down to the soft x-ray region, using a set of thin circular gold bands made self supporting by radial struts.
Abstract: A new type of Fresnel zone plate has been constructed which can focus ultraviolet radiation of any wavelength down to the soft x-ray region. It consists of a set of thin circular gold bands made self supporting by radial struts, leaving the transparent zones empty. Experimental tests at 6700, 4358, and 2537 A showed that the theoretical minimum angular resolution obeys the Rayleigh criterion, sinθmin=1.22λ/D. The diameter of the zone plate is D=0.26 cm and contains 19 opaque zones, the narrowest of which measured about 20 μ across. The zone plate was better than the optimum pinhole in resolution by a factor of about 6 and in speed by a factor of 40. The zone plate produced pictures that compared favorably with those made with a lens of similar focal length and aperture. The lens was about 20 times faster than the zone plate at 4358 A, but at 1000 A the zone plate would have been far faster than the lens. Focusing tests are contemplated at 1000 A and at 100 A where lenses and mirrors, the conventional image-forming devices, may fail. The angular resolution at 2537 A was close to the theoretical value of 1.2×10−4 rad and held over a field of at least 1.75×10−2 rad, which is 2.0 times the angle subtended by the sun’s disk at the earth. A zone plate telescope, operating in the soft x-ray or extreme ultraviolet region, far above the earth’s atmosphere in an orbiting satellite, now seems possible.

142 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]....

    [...]

Journal ArticleDOI
TL;DR: In this paper, a diffractive Fresnel zone plate lens was used for short wavelength x-ray radiation microscopy at the Advanced Light Source Synchrotron in Berkeley, California.
Abstract: Short wavelength x-ray radiation microscopy is well suited for a number of material and life science studies. The x-ray microscope (XM1) at the Advanced Light Source Synchrotron in Berkeley, California uses two diffractive Fresnel zone plate lenses. The first is a large condenser lens, which collects soft x-ray radiation from a bending magnet, focuses it, and serves as a linear monochromator. The second is the objective zone plate lens, which magnifies the image of the specimen onto a high-efficiency charge coupled device detector. The objective lens determines the numerical aperture and ultimate resolution. New objective lens zone plates with a minimum linewidth of 25 nm and excellent linewidth control have been fabricated using Berkeley Lab’s 100 keV Nanowriter electron beam lithography tool, a calixarene high-resolution negative resist, and gold electroplating. Although the condenser zone plate is less critical to the resolution of the instrument, its efficiency determines the flux on the sample and ul...

129 citations

Journal Article

127 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]....

    [...]