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Ohno H, Toya K. Localized gradient-index field reconstruction using background-oriented schlieren. APPLIED OPTICS 2019; 58:7795-7804. [PMID: 31674463 DOI: 10.1364/ao.58.007795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
A method to reconstruct a localized gradient-index field using the background-oriented schlieren (BOS) technique is proposed here. The BOS technique can measure deflection angles of light rays passing through the gradient-index field. When a gradient-index field is localized in a limited area, a scalar potential that is the integral of the gradient-index field over the light ray path can be transformed in the form of the integral of the deflection angle over the localized area. The gradient-index field is then derived from the scalar potential assuming that the field is axisymmetric. When the gradient-index is anisotropic, a light ray path depends on its polarization. The localized reconstruction method is applicable not only to the isotropic gradient-index field but also to such anisotropic field. An anisotropic gradient-index field can be experimentally generated by applying stress to a glass block with a resin sphere that contacts the glass block at a point. The anisotropic gradient-index field can be reconstructed using the localized reconstruction method, and it agrees with that of theoretical calculation using structural analysis software.
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2
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Ohno H, Toya K. Scalar potential reconstruction method of axisymmetric 3D refractive index fields with background-oriented schlieren. OPTICS EXPRESS 2019; 27:5990-6002. [PMID: 30876193 DOI: 10.1364/oe.27.005990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/09/2019] [Indexed: 06/09/2023]
Abstract
Deflection angles of light rays passing through a refractive index field can be measured by the background-oriented schlieren (BOS) technique. Assuming that the deflection angle is sufficiently small and the paraxial approximation can apply to the light rays, a vector consisting of deflection angles in two orthogonal directions is shown to be derived from a gradient of a scalar potential. The scalar potential can be written as an integration of the refractive index field over the light ray path. Thus, a method to reconstruct an axisymmetric 3D refractive index field with the scalar potential is proposed here. An arbitrary measured deflection angle vector, however, is generally written not only with a scalar potential but with a vector potential. Thus, the Poisson's equation is derived to extract a scalar potential from a measured deflection angle vector. The axisymmetric 3D refractive index field is able to be reconstructed using the Abel transformation [1] of the scalar potential derived by applying the 2D Fourier transformation to the Poisson's equation. The scalar potential reconstruction method is validated by reconstructing a spherically symmetric refractive index field where a deflection angle vector field is able to be calculated accurately.
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Smartphone-based multi-contrast microscope using color-multiplexed illumination. Sci Rep 2017; 7:7564. [PMID: 28790342 PMCID: PMC5548908 DOI: 10.1038/s41598-017-07703-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/03/2017] [Indexed: 11/22/2022] Open
Abstract
We present a portable multi-contrast microscope capable of producing bright-field, dark-field, and differential phase contrast images of thin biological specimens on a smartphone platform. The microscopy method is based on an imaging scheme termed “color-coded light-emitting-diode (LED) microscopy (cLEDscope),” in which a specimen is illuminated with a color-coded LED array and light transmitted through the specimen is recorded by a color image sensor. Decomposition of the image into red, green, and blue colors and subsequent computation enable multi-contrast imaging in a single shot. In order to transform a smartphone into a multi-contrast imaging device, we developed an add-on module composed of a patterned color micro-LED array, specimen stage, and miniature objective. Simple installation of this module onto a smartphone enables multi-contrast imaging of transparent specimens. In addition, an Android-based app was implemented to acquire an image, perform the associated computation, and display the multi-contrast images in real time. Herein, the details of our smartphone module and experimental demonstrations with various biological specimens are presented.
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Ba C, Palmiere M, Ritt J, Mertz J. Dual-modality endomicroscopy with co-registered fluorescence and phase contrast. BIOMEDICAL OPTICS EXPRESS 2016; 7:3403-3411. [PMID: 27699107 PMCID: PMC5030019 DOI: 10.1364/boe.7.003403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/08/2016] [Accepted: 08/08/2016] [Indexed: 05/09/2023]
Abstract
We describe a dual-modality laser scanning endomicroscope that provides simultaneous fluorescence contrast based on confocal laser endomicroscopy (CLE) and phase-gradient contrast based on scanning oblique back-scattering microscopy (sOBM). The probe consists of a 2.6mm-diameter micro-objective attached to a 30,000-core flexible fiber bundle. The dual contrasts are inherently co-registered, providing complementary information on labeled and un-labeled sample structure. Proof of principle demonstrations are presented with ex-vivo mouse colon tissue.
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Lee D, Ryu S, Kim U, Jung D, Joo C. Color-coded LED microscopy for multi-contrast and quantitative phase-gradient imaging. BIOMEDICAL OPTICS EXPRESS 2015; 6:4912-22. [PMID: 26713205 PMCID: PMC4679265 DOI: 10.1364/boe.6.004912] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/02/2015] [Accepted: 11/15/2015] [Indexed: 05/12/2023]
Abstract
We present a multi-contrast microscope based on color-coded illumination and computation. A programmable three-color light-emitting diode (LED) array illuminates a specimen, in which each color corresponds to a different illumination angle. A single color image sensor records light transmitted through the specimen, and images at each color channel are then separated and utilized to obtain bright-field, dark-field, and differential phase contrast (DPC) images simultaneously. Quantitative phase imaging is also achieved based on DPC images acquired with two different LED illumination patterns. The multi-contrast and quantitative phase imaging capabilities of our method are demonstrated by presenting images of various transparent biological samples.
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Sulai YN, Scoles D, Harvey Z, Dubra A. Visualization of retinal vascular structure and perfusion with a nonconfocal adaptive optics scanning light ophthalmoscope. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:569-79. [PMID: 24690655 PMCID: PMC4465430 DOI: 10.1364/josaa.31.000569] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Imaging of the retinal vascular structure and perfusion was explored by confocal illumination and nonconfocal detection in an adaptive optics scanning light ophthalmoscope (AOSLO), as an extension of the work by Chui et al. [Biomed. Opt. Express 3, 2537 (2012)]. Five different detection schemes were evaluated at multiple retinal locations: circular mask, annular mask, circular mask with filament, knife-edge, and split-detector. Given the superior image contrast in the reflectance and perfusion maps, the split-detection method was further tested using pupil apodization, polarized detection, and four different wavelengths. None of these variations provided noticeable contrast improvement. The noninvasive visualization of capillary flow and structure provided by AOSLO split-detection shows great promise for studying ocular and systemic conditions that affect the retinal vasculature.
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Affiliation(s)
- Yusufu N. Sulai
- The Institute of Optics, University of Rochester, Rochester, New York 14627, USA
| | - Drew Scoles
- Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, USA
| | - Zachary Harvey
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
| | - Alfredo Dubra
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
- Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233, USA
- Corresponding author:
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7
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McLeod RR, Daiber AJ, Honda T, McDonald ME, Robertson TL, Slagle T, Sochava SL, Hesselink L. Three-dimensional optical disk data storage via the localized alteration of a format hologram. APPLIED OPTICS 2008; 47:2696-2707. [PMID: 18470266 DOI: 10.1364/ao.47.002696] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Three-dimensional optical data storage is demonstrated in an initially homogenous volume by first recording a reflection grating in a holographic photopolymer. This causes the entire volume to be weakly reflecting to a confocal read/write head. Superposition of two or three such gratings with slightly different k-vectors creates a track and layer structure that specialized servo detection optics can use to lock the focus to these deeply-buried tracks. Writing is accomplished by locally modifying the reflectivity of the preexisting hologram. This modification can take the form of ablation, inelastic deformation via heating at the focus, or erasure via linear or two-photon continued polymerization in the previously unexposed fringes of the hologram. Storage by each method is demonstrated with up to eight data layers separated by as little as 12 microns.
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Affiliation(s)
- R R McLeod
- Department of Electrical and Computer Engineering, University of Colorado, Boulder, CO 80309, USA.
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Ayres MR, McLeod RR. Scanning transmission microscopy using a position-sensitive detector. APPLIED OPTICS 2006; 45:8410-8. [PMID: 17086248 DOI: 10.1364/ao.45.008410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Optical data manipulation technologies increasingly employ densely aperiodic optical 3D phase elements. Refinement of such technologies will require the capability to quantitatively characterize the volumetric dielectric modulation of an optical sample to a high level of precision and spatial resolution. We present a scanning transmission microscopy system that uses a position-sensitive detector to impart sensitivity to both the phase and absorption components. We describe the layout of the instrument and then derive its phase and absorption transfer functions. Simulations and experiments are presented to validate the analysis. For phase detection, the instrument possesses depth-sectioning properties similar to those of a confocal microscope without the use of a pinhole, enabling full 3D object reconstruction.
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Affiliation(s)
- Mark R Ayres
- InPhase Technologies Inc., 2000 Pike Road, Longmont, CO 80501, USA.
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McLeod RR, Daiber AJ, McDonald ME, Robertson TL, Slagle T, Sochava SL, Hesselink L. Microholographic multilayer optical disk data storage. APPLIED OPTICS 2005; 44:3197-207. [PMID: 15943253 DOI: 10.1364/ao.44.003197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Micrometer-sized reflection holograms can be written into a rapidly rotating homogeneous photopolymer disk at the focus of a high-numerical-aperture beam and its retroreflection to implement high-capacity multilayer digital data storage. This retroreflection is generated by an optical system with positive unity magnification to ensure passive alignment of the counterpropagating beam. Analysis reveals that the storage capacity and transfer rate of this bit-based holographic storage system compare favorably with traditional page-based systems but at a fraction of the system complexity and cost. The analysis is experimentally validated at 532 nm by writing and reading 12 layers of microholograms in a 125-microm photopolymer disk continuously rotating at 3600 rpm. The experimental results predict a capacity limit of 140 Gbytes in a millimeter-thick disk or over 1 Tbyte with the wavelength and numerical aperture of Blu-Ray.
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Kawata S, Kawata Y. Three-Dimensional Optical Data Storage Using Photochromic Materials. Chem Rev 2000; 100:1777-1788. [PMID: 11777420 DOI: 10.1021/cr980073p] [Citation(s) in RCA: 799] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Satoshi Kawata
- Department of Applied Physics, Osaka University, Suita, Osaka, 565-0871, Japan, and Department of Mechanical Engineering, Shizuoka University, Johoku, Hamamatsu, 432-8561, Japan
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Wang MM, Esener SC. Three-dimensional optical data storage in a fluorescent dye-doped photopolymer. APPLIED OPTICS 2000; 39:1826-1834. [PMID: 18345079 DOI: 10.1364/ao.39.001826] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We propose a new, to our knowledge, monolithic multilayer optical storage medium in which data may be stored through the diffusional redistribution of fluorescent molecules within a polymer host. The active portion of the medium consists of a photopolymer doped with a fluorescent dye that is polymerized at the focal point of a high-numerical-aperture lens. We believe that as fluorescent molecules bond to the polymer matrix they become more highly concentrated in the polymerized regions, resulting in the modulated data pattern. Since data readout is based on detection of fluorescence rather than index modulation as in other photopolymer-based memories, the problems of media shrinkage and optical scatter are of less concern. An intensity threshold observed in the recording response of this material due to the presence of inhibitor molecules in the photopolymer allows for the three-dimensional confinement of recorded bits and therefore multilayer recording. The nonlinear recording characteristics of this material were investigated through a simple model of photopolymerization and diffusion and verified experimentally. Both single-layer and multilayer recordings were demonstrated.
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Affiliation(s)
- M M Wang
- Department of Electrical and Computer Engineering, University of California at San Diego, La Jolla, California 92093, USA.
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Toriumi A, Herrmann JM, Kawata S. Nondestructive readout of a three-dimensional photochromic optical memory with a near-infrared differential phase-contrast microscope. OPTICS LETTERS 1997; 22:555-557. [PMID: 18183265 DOI: 10.1364/ol.22.000555] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A three-dimensional (3D) rewritable optical memory using photochromic material is described for high-density memory. The bits are recorded in a 3D volume of photochromic material. A transformation of the photochromic molecule between two isomers with different absorption spectra can be stimulated by irradiation with appropriate wavelengths. We show that a nondestructive readout of photochromic memory is possible by use of a small difference in the refractive index of the photochromic isomers in the near-IR range. For this purpose a near-IR laser-scan differential phase-contrast microscope is used. Experimental results of 3D recording and nondestructive reading are presented.
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Kawata Y, Tanaka T, Kawata S. Randomly accessible, multilayered optical memory with a Bi(12)SiO(20) crystal. APPLIED OPTICS 1996; 35:5308-5311. [PMID: 21127523 DOI: 10.1364/ao.35.005308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A read-and-write, randomly accessible, multilayered optical memory with a Bi(12) SiO(20) crystal as the medium is demonstrated. Data are recorded in the crystal as an absorption change that is due to the photochromic effect. These data are successfully recorded, read, and selectively erased in five layers in the crystal. The axial-separation distance between neighboring layers is 30 μm, and the lateral distance between bits is 5 μm. Selective bit erasure of the data is accomplished by illumination of the recorded bit datum with He-Ne laser light. To our knowledge, this is the first successful demonstration of the selective optical erasure of the photochromic effect in a BSO crystal.
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