Colin J R Sheppard

Summary

Publications

  1. ncbi request reprint Superresolution by image scanning microscopy using pixel reassignment
    Colin J R Sheppard
    Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
    Opt Lett 38:2889-92. 2013
  2. doi request reprint Limitations of the paraxial Debye approximation
    Colin J R Sheppard
    Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
    Opt Lett 38:1074-6. 2013
  3. doi request reprint Pupil filters for generation of light sheets
    Colin J R Sheppard
    Italian Institute of Technology, Via Morego 30, Genova 16163, Italy
    Opt Express 21:6339-45. 2013
  4. doi request reprint Complex source point theory of paraxial and nonparaxial cosine-Gauss and Bessel-Gauss beams
    Colin J R Sheppard
    Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163, Italy Singapore MIT Alliance for Research and Technology SMART Centre, 1 CREATE Way, Singapore 138602, Singapore
    Opt Lett 38:564-6. 2013
  5. doi request reprint Cylindrical lenses--focusing and imaging: a review [Invited]
    Colin J R Sheppard
    Italian Institute of Technology, Genova, Italy
    Appl Opt 52:538-45. 2013
  6. doi request reprint Three-level filter for increased depth of focus and Bessel beam generation
    Colin J R Sheppard
    Italian Institute of Technology, Genova 16163, Italy
    Opt Express 20:27212-21. 2012
  7. doi request reprint Geometric representation for partial polarization in three dimensions
    Colin J R Sheppard
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore, Singapore 117574
    Opt Lett 37:2772-4. 2012
  8. doi request reprint A complete and computationally efficient numerical model of aplanatic solid immersion lens scanning microscope
    Rui Chen
    Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576
    Opt Express 21:14316-30. 2013
  9. doi request reprint Focal modulation microscopy with annular apertures: a numerical study
    Wei Gong
    Division of Bioengineering, National University of Singapore, Singapore, Singapore
    J Biophotonics 3:476-84. 2010
  10. doi request reprint Sample-less calibration of the differential interference contrast microscope
    Shalin B Mehta
    1Optical Bioimaging Lab, Division of Bioengineering, National University of Singapore, Block E3A, 7 10, 7 Engineering Drive 1, Singapore 117574
    Appl Opt 49:2954-68. 2010

Collaborators

Detail Information

Publications27

  1. ncbi request reprint Superresolution by image scanning microscopy using pixel reassignment
    Colin J R Sheppard
    Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
    Opt Lett 38:2889-92. 2013
    ..With no Stokes shift, the width of the point spread function can be sharpened by a factor of 1.53, and its peak intensity increased by a factor of 1.84. ..
  2. doi request reprint Limitations of the paraxial Debye approximation
    Colin J R Sheppard
    Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
    Opt Lett 38:1074-6. 2013
    ..The aberrations of a glass slab, such as a coverslip, are expanded in terms of the new variable, and expressed in terms of Zernike polynomials to assist with aberration balancing. Tube length error is also discussed...
  3. doi request reprint Pupil filters for generation of light sheets
    Colin J R Sheppard
    Italian Institute of Technology, Via Morego 30, Genova 16163, Italy
    Opt Express 21:6339-45. 2013
    ..An important application is in generating light sheets with uniform intensity. Filters for spherical (three-dimensional) focusing with a flat axial intensity, coupled with weak side lobes are also discussed...
  4. doi request reprint Complex source point theory of paraxial and nonparaxial cosine-Gauss and Bessel-Gauss beams
    Colin J R Sheppard
    Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163, Italy Singapore MIT Alliance for Research and Technology SMART Centre, 1 CREATE Way, Singapore 138602, Singapore
    Opt Lett 38:564-6. 2013
    ..A way to generate nonparaxial Bessel-Gauss beams is also indicated...
  5. doi request reprint Cylindrical lenses--focusing and imaging: a review [Invited]
    Colin J R Sheppard
    Italian Institute of Technology, Genova, Italy
    Appl Opt 52:538-45. 2013
    ..Nonparaxial lenses are also discussed...
  6. doi request reprint Three-level filter for increased depth of focus and Bessel beam generation
    Colin J R Sheppard
    Italian Institute of Technology, Genova 16163, Italy
    Opt Express 20:27212-21. 2012
    ..Effects of discretization are discussed. Various different approaches to increasing depth of focus are compared, to put the new design into perspective...
  7. doi request reprint Geometric representation for partial polarization in three dimensions
    Colin J R Sheppard
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore, Singapore 117574
    Opt Lett 37:2772-4. 2012
    ..This composition plot is an alternative to the spherical plot recently used to illustrate the degree of polarization in terms of entanglement...
  8. doi request reprint A complete and computationally efficient numerical model of aplanatic solid immersion lens scanning microscope
    Rui Chen
    Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576
    Opt Express 21:14316-30. 2013
    ....
  9. doi request reprint Focal modulation microscopy with annular apertures: a numerical study
    Wei Gong
    Division of Bioengineering, National University of Singapore, Singapore, Singapore
    J Biophotonics 3:476-84. 2010
    ..The capability of background rejection is also investigated, showing AFMM has the potential to further increase the imaging penetration depth. Finally, an optimal configuration of AFMM is elaborated...
  10. doi request reprint Sample-less calibration of the differential interference contrast microscope
    Shalin B Mehta
    1Optical Bioimaging Lab, Division of Bioengineering, National University of Singapore, Block E3A, 7 10, 7 Engineering Drive 1, Singapore 117574
    Appl Opt 49:2954-68. 2010
    ..The method presented is accurate, relies on simple image analysis, and does not require a specimen. We provide a succinct and accurate description of properties of Nomarski prisms to explain the rationale behind the method...
  11. doi request reprint Edge enhancement for in-phase focal modulation microscope
    Ke Si
    Graduate School for Integrative Sciences and Engineering, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
    Appl Opt 48:6290-5. 2009
    ..4% and 58.9% for a thick edge and a thin edge, respectively. Signal level is also discussed, and the results show that, to obtain high transverse resolution with IPFMM, the normalized detector pinhole radius should not exceed 2.8...
  12. doi request reprint Motion detection using extended fractional Fourier transform and digital speckle photography
    Basanta Bhaduri
    1Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore
    Opt Express 18:11396-405. 2010
    ..The dynamic range and sensitivity of the measurement can be varied readily by altering the position of the mirror/s used in the optical setup. Theoretical analysis and experiment results are presented...
  13. doi request reprint Reconstruction in interferometric synthetic aperture microscopy: comparison with optical coherence tomography and digital holographic microscopy
    Colin J R Sheppard
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore, Singapore
    J Opt Soc Am A Opt Image Sci Vis 29:244-50. 2012
    ..The spatial frequency response is developed based on the three-dimensional coherent transfer function approach and compared with that in optical coherence tomography and digital holographic microscopy...
  14. ncbi request reprint Focal modulation microscopy: a theoretical study
    Shau Poh Chong
    Division of Bioengineering, National University of Singapore, 9 Engineering Drive 1, EA 03 12, Singapore 129789
    Opt Lett 35:1804-6. 2010
    ..The scalar diffraction theory is combined with Monte Carlo simulation to evaluate the signal-to-background ratio at various depths. The performance of confocal microscopy with a similar optical setup is also evaluated for comparison...
  15. doi request reprint Considerations of aperture configuration in focal modulation microscopy from the standpoint of modulation depth
    Guangjun Gao
    Division of Bioengineering, National University of Singapore, Singapore 117576
    J Opt Soc Am A Opt Image Sci Vis 28:496-501. 2011
    ..In summary, the annular configuration is superior to the fan- and stripe-shaped configurations in modulation depth and spatial resolution...
  16. ncbi request reprint Polarization conversion in confocal microscopy with radially polarized illumination
    Wai Teng Tang
    Computation and Systems Biology, Singapore MIT Alliance, National University of Singapore, Singapore
    Opt Lett 34:2147-9. 2009
    ....
  17. pmc Temporally focused wide-field two-photon microscopy: paraxial to vectorial
    Elijah Y S Yew
    Singapore MIT Alliance for Research and Technology, 1 CREATE Way, 10 01 CREATE Tower, Singapore 138602, Singapore
    Opt Express 21:12951-63. 2013
    ....
  18. doi request reprint Quantitative phase restoration by direct inversion using the optical transfer function
    Shan Shan Kou
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore NUS, 7 Engineering Drive 1, 117576, Singapore
    Opt Lett 36:2671-3. 2011
    ..The proposed method is especially suitable for application to weak phase objects, such as live and unstained biological samples but, surprisingly, has also been shown to work with comparatively strong phase objects...
  19. doi request reprint Resolution of aplanatic solid immersion lens based microscopy
    Rui Chen
    Department of Electrical and Computer Engineering, National University of Singapore, Singapore
    J Opt Soc Am A Opt Image Sci Vis 29:1059-70. 2012
    ..The observations are explained explicitly through a detailed analysis of the dyadic Green's function. A new resolution criterion is also proposed, which provides a very accurate estimate of the resolution limits...
  20. ncbi request reprint Optical color-image encryption and synthesis using coherent diffractive imaging in the Fresnel domain
    Wen Chen
    Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576, Singapore
    Opt Express 20:3853-65. 2012
    ..Compared with conventional interference methods, coherent diffractive imaging approach may open up a new research perspective or can provide an effective alternative for optical color-image encryption and synthesis...
  21. doi request reprint Multipole theory for tight focusing of polarized light, including radially polarized and other special cases
    Thanh Xuan Hoang
    Department of Electrical and Computer Engineering, National University of Singapore, Singapore
    J Opt Soc Am A Opt Image Sci Vis 29:32-43. 2012
    ..The method is also convenient for calculation of fields scattered by particles and calculation of optical trapping forces...
  22. doi request reprint Optical double-image cryptography based on diffractive imaging with a laterally-translated phase grating
    Wen Chen
    Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576, Singapore
    Appl Opt 50:5750-7. 2011
    ..In addition, security and advantages of the proposed method are analyzed. Feasibility and effectiveness of the proposed method are demonstrated by numerical simulation results...
  23. doi request reprint Transport-of-intensity approach to differential interference contrast (TI-DIC) microscopy for quantitative phase imaging
    Shan Shan Kou
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576, Singapore
    Opt Lett 35:447-9. 2010
    ..Numerically solving for the propagation of light in a series of through-focus DIC images allows linear phase information in a single slice to be completely determined and restored from DIC intensity values...
  24. ncbi request reprint Recent advances in optical microscopy methods for subcellular imaging of thick biological tissues
    NanGuang Chen
    Department of Biomedical Engineering, National University of Singapore, Singapore
    Crit Rev Biomed Eng 41:393-403. 2013
    ..Focal modulation microscopy has demonstrated an imaging depth comparable to those of multiphoton microscopy and optical coherence microscopy, near-real-time image acquisition, and capability with a multiple contrast mechanism. ..
  25. doi request reprint Binary phase filters with a maximally-flat response
    Colin J R Sheppard
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore, Singapore 117574
    Opt Lett 36:1386-8. 2011
    ..Solutions are obtained by direct algebraic manipulation, and numerical results are given for filters of up to five elements. Their application for increasing depth of focus is described...
  26. doi request reprint Phase-space representation of partially coherent imaging systems using the Cohen class distribution
    Shalin B Mehta
    Optical Bioimaging Laboratory, Division of Bioengineering, National University of Singapore, Block E3A, 7 10, 7 Engineering Drive 1, Singapore 118431
    Opt Lett 35:348-50. 2010
    ..It uses only the requisite number of dimensions and leads to an efficient algorithm for calculating images. Computed partially coherent images of a double slit and a two-dimensional sinusoidal spoke are presented...
  27. doi request reprint Divided-aperture technique for fluorescence confocal microscopy through scattering media
    Wei Gong
    Division of Bioengineering, National University of Singapore, Singapore 117574
    Appl Opt 49:752-7. 2010
    ..For a given detector size, an optimum value of the divider strip width is given to obtain the best axial resolution or transverse resolution. The integrated intensity and signal-to-background ratio are also discussed...