New class of axially apodizing filters for confocal scanning microscopy

Boyer, Gilbert

doi:10.1364/josaa.19.000584

Cited by 36 publications

(13 citation statements)

References 23 publications

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“…Modified versions of toraldo filter have also been employed to improve the axial resolution of confocal systems [53][54][55]. There have been other reports of resolution improvement in confocal systems with appropriate modification of the illumination and detection paths [56,57].…”

Section: Point Spread Function Engineeringmentioning

confidence: 99%

Programmable diffractive optics for laser scanning confocal microscopy

Boruah

Neil

2007

SPIE Proceedings

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Coherent light beams find applications in several exciting research areas where it is important to have absolute control over the phase and amplitude properties of the light beams.To name a few, in applications such as microscopy, optical trapping, interferometry etc. it is imperative to have dynamic control over the properties of the beam. One way of achieving this is with the help of a computer controlled diffractive optical element such as a liquid crystal spatial light modulator (LCSLM). Based on the principle of holography, such a technique can provide dynamic control over amplitude, phase and polarisation state across a coherent beam.This work describes about a ferro-electric liquid crystal spatial light modulator (FLC-SLM) system acting as a programmable diffractive optical element. The efficiency of the system to detect and correct aberrations in laser beams were demonstrated. The ultra sensitivity of singular light beams to the presence of azimuthal aberrations were observed and a novel aberration sensor based on these findings were implemented. The synchronisation of the display holograms on the FLCSLM panel with the acquisition of a CCD camera is demonstrated in a programmable reference beam phase stepping interferometry experiment.Laser scanning confocal microscopy is a widely used technique for the electronic visualization of optically sectioned microscopic structures. The information available from such a system is limited by the intensity and polarisation properties of the point spread function (PSF) at the sample plane, which are in turn dependent on the optical system and the sample being imaged. Aberrations due to incorrect optics or the sample itself may significantly degrade the PSF there by reducing the resolution and the signal available for image formation. Also the information obtained from a laser scanning confocal system working in the epi-fluorescence mode will also depend on the polarisation properties of the PSF, as molecular absorption and emission cross-sections are polarisation dependant. These polarisation properties can be particularly important for high resolution microscopy such as STED and molecular alignment studies when high numerical aperture lenses are used that can result in complex polarisation structure within the PSF. The thesis develops the theory necessary to understand the vectorial behaviour of the 3D PSF for an arbitrarily polarised beam. The design and implementation of a beam scanning optical microscope system, that uses an FLCSLM to control the optical field in the illumination pupil of the microscope objective, are described. The performance of the system in engineering and reconfiguring the 3D PSF is demonstrated. Use of programmable diffractive optics to generate different depletion beams for STED microscopy is also demonstrated. 2To My Parents 3

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Section: Point Spread Function Engineeringmentioning

confidence: 99%

Programmable diffractive optics for laser scanning confocal microscopy

Boruah

Neil

2007

SPIE Proceedings

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“…These properties plays an important role in modern science and technology, with numerous applications, such as data storage [1] ,optical communication, astronomy [2,3] , confocal scanning microscopy [4,5] , laser printing, free space laser communication [6] , optical trap. One such example of optical trap is called optical tweezer.…”

Section: Introductionmentioning

confidence: 99%

Optical tweezers formed by pure phase pupil filter

You

Wang

et al. 2013

SPIE Proceedings

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The focusing properties of vector beams have attracted great attention and quickly became the subject of extensive worldwide research due to their applications in lithography, optical storage, microscopy, material processing, and optical trapping. Focusing properties of the radially polarized beam and generalized cylindrical vector beams in high numerical aperture system with designed pure phase filter are analyzed in detail by using vector Debye diffraction theory. By utilizing diffractive optical element to partly change the polarization of vector beams, the energy density of light field in the vicinity of focus is studied by the numerical analysis. Numerical simulation result shows that optical bubbles can be obtained by changing the composition and polarization of the incident beams. At last, optical tweezers are constituted by two optical bubbles around the focus.

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“…This diffractionlimited resolution can be further improved by techniques generally referred to as superresolution [9]. Superresolution is achieved by controlling the phase and/or amplitude of the laser beam and has shown considerable impact for many applications such as confocal scanning microscopy [10–12] or optical data storage [13–15]. In this case, a diffractive filter is placed at the exit pupil of an optical system, as depicted in figure 1.…”

Section: Introductionmentioning

confidence: 99%