Dynamic speckle illumination microscopy with translated versus randomized speckle patterns

Author(s): Cathie Ventalon and Jerome Mertz

Abstract:

“Dynamic speckle illumination (DSI) microscopy is a widefield fluorescence imaging technique that provides depth discrimination. The technique relies on the illumination of a sample with a sequence of speckle patterns. We consider an image processing algorithm based on a differential intensity variance between consecutive images, and demonstrate that DSI sectioning strength depends on the dynamics of the speckle pattern. Translated speckle patterns confer greater sectioning strength than randomized speckle patterns because they retain out-of-focus correlations that lead to better background rejection. We present a theory valid for arbitrary point-spread-functions, which we corroborate with experimental results.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 14, Issue 16, pp. 7198-7209
doi:10.1364/OE.14.007198

Polarization encoding and multiplexing of two-dimensional signals: application to image encryption

Author(s): Unnikrishnan Gopinathan, Thomas J. Naughton, and John T. Sheridan

Abstract:

“We discuss an optical system that encodes an input signal to a polarization state, using a spatial light modulator (SLM). Using two SLMs the optical system multiplexes two 2D signals in the polarization domain, and we demonstrate the multiplexing of two binary images. The encryption and decryption of two binary images using an xor operation is also presented.”

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Publication: Applied Optics (subscription required)

Issue/Year/DOI: Applied Optics, Vol. 45, Issue 22, pp. 5693-5700
doi:10.1364/AO.45.005693

Generation of achromatic Bessel beams using a compensated spatial light modulator

Author(s): Jonathan Leach, Graham M. Gibson, Miles J. Padgett, Elric Esposito, Gail McConnell, Amanda J. Wright, and John M. Girkin

Abstract:

“We report the creation of white-light, achromatic Bessel beams using a spatial light modulator and a prism to compensate for the dispersion. Unlike the Bessel beam created by a refractive axicon, this achromatic beam has a radial wavevector and hence an intensity cross-section which is independent of wavelength. The technique also lends itself to the generation of higher order Bessel beams with an on-axis optical vortex and associated orbital angular momentum.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 14, Issue 12, pp. 5581-5587
doi:10.1364/OE.14.005581

Dynamisches System für die Aufnahme und optische Rekonstruktion von digitalen Hologrammen

Author(s): G. Wernicke, J. Frank, C. Günther, S. Krüger

Abstract:

“Es wird ein Aufbau zur Aufnahme und optischen Rekonstruktion von digitalen Hologrammen unter Verwendung von reflektiven Flüssigkristalldisplays vorgestellt. Anwendungen mit einer speziell modulierten Beleuchtung bei der Aufnahme zur Darstellung von holographischen Interferogrammen und die optische Rekonstruktion von Röntgenhologrammen wird gezeigt.”

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Publication: DGaO Proceedings, (free download)

ISSN: 1614-8436

Dynamisches System für die Aufnahme und optische Rekonstruktion von Hologrammen

Author(s): Günther Wernicke, Johannes Frank, Christian Günther, Sven Krüger

Abstract:

“Adressierbare räumliche Lichtmodulatoren mit einer möglichst idealen Phasenmodulation sind die Voraussetzung für deren Anwendung in der digitalen Holographie. Eine angepasste Treiberelektronik und eine genaue Kenntnis des Modulationsverhaltens kann zu einem dynamischen Phasenmodulations-System mit nahezu linearer Kennlinie und einem maximalen Phasenhub von 2 pi führen.
Ein System zur Aufnahme und Rekonstruktion von digitalen Hologrammen mit digitaler Bearbeitung der Hologrammdaten wird gezeigt. Daten von einer CCD-Kamera werden in den PC eingelesen und von diesem auf den Lichtmodulator gegeben. Damit wird ein Analog-Digital-Konverter (Hologrammaufnahme) und ein Digital-Analog-Konverter (optische Hologrammrekonstruktion) realisiert. Das Auflösungsvermögen wird diskutiert und Anwendungsmöglichkeiten, insbesondere durch Manipulationen am rekonstruierten Wellenfeld werden gezeigt.
Damit werden neue Anwendungen in der zerstörungsfreien holographischen Prüfung und in der holographischen Mikroskopie und der Kombination von beiden möglich. ”

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Publication: DGaO-Proceedings 2006, (free download)

Issue/Year/DOI: DGaO-Proceedings 2006, 107. Tagung, Vortrag: B36,
ISSN: 1614-8436

Spiral interferogram analysis

Author(s): Alexander Jesacher, Severin Fürhapter, Stefan Bernet, and Monika Ritsch-Marte

Abstract:

“Interference microscopy using spatial Fourier filtering with a vortex phase element leads to interference fringes that are spirals rather than closed rings. Depressions and elevations in the optical thickness of the sample can be distinguished immediately by the sense of rotation of the spirals. This property allows an unambiguous reconstruction of the object’s phase profile from one single interferogram. We investigate the theoretical background of “spiral interferometry” and suggest various demodulation techniques based on the processing of one single interferogram or multiple interferograms.”

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Publication: Journal of the Optical Society of America A (subscription required)

Issue/Year/DOI: JOSA A, Vol. 23, Issue 6, pp. 1400-1409 (2006)
doi:10.1364/JOSAA.23.001400

Quantitative imaging of complex samples by spiral phase contrast microscopy

Author(s): Stefan Bernet, Alexander Jesacher, Severin Fürhapter, Christian Maurer, and Monika Ritsch-Marte

Abstract:

“Recently a spatial spiral phase filter in a Fourier plane of a microscopic imaging setup has been demonstrated to produce edge enhancement and relief-like shadow formation of amplitude and phase samples. Here we demonstrate that a sequence of at least 3 spatially filtered images, which are recorded with different rotational orientations of the spiral phase plate, can be used to obtain a quantitative reconstruction of both, amplitude and phase information of a complex microscopic sample, i.e. an object consisting of mixed absorptive and refractive components. The method is demonstrated using a calibrated phase sample, and an epithelial cheek cell.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 14, Issue 9, pp. 3792-3805
doi:10.1364/OE.14.003792

Synthesis of multiple collinear helical modes generated by a phase-only element

Author(s): Jiao Lin, Xiaocong Yuan, Shaohua H. Tao, and Ronald E. Burge

Abstract:

“Phase-only elements are generally more desirable than complex-amplitude-modulated elements not only because of the higher diffraction efficiency but the readier implementation and fabrication. A novel iterative algorithm is proposed for generating multiple helical modes by a single phase-only element. A superposition of four helical modes is demonstrated experimentally by using a spatial light modulator.”

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Publication: Journal of the Optical Society of America A, (subscription required)

Issue/Year/DOI: JOSA A, Vol. 23, Issue 5, pp. 1214-1218
doi:10.1364/JOSAA.23.001214

Aberration correction in holographic optical tweezers

Author(s): Kurt D. Wulff, Daniel G. Cole, Robert L. Clark, Roberto DiLeonardo, Jonathan Leach, Jon Cooper, Graham Gibson, and Miles J. Padgett

Abstract:

“Holographic or diffractive optical components are widely implemented using spatial light modulators within optical tweezers to form multiple, and/or modified traps. We show that by further modifying the hologram design to account for residual aberrations, the fidelity of the focused beams can be significantly improved, quantified by a spot sharpness metric. However, the impact this improvement has on the quality of the optical trap depends upon the particle size. For particle diameters on the order of 1 µm, aberration correction can improve the trap performance metric, which is the ratio of the mean square displacement of a corrected trap to an uncorrected trap, in excess of 25%, but for larger particles the trap performance is not unduly affected by the aberrations typically encountered in commercial spatial light modulators.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 14, Issue 9, pp. 4169-4174
doi:10.1364/OE.14.004169

Holographic optical trapping of aerosol droplets

Author(s): D. R. Burnham and D. McGloin

Abstract:

“We demonstrate the use of holographic optical tweezers for trapping particles in air, specifically aerosol droplets. We show the trapping and manipulation of arrays of liquid aerosols as well as the controlled coagulation of two or more droplets. We discuss the ability of spatial light modulators to manipulate airborne droplets in real time as well as highlight the difficulties associated with loading and trapping particles in such an environment. We conclude with a discussion of some of the applications of such a technique.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 14, Issue 9, pp. 4175-4181
doi:10.1364/OE.14.004175

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