Microscopy of biological sample through advanced diffractive optics from visible to x-ray wavelength regime

Di Fabrizio, Enzo and Cojoc, Dan and Emiliani, Valentina and Cabrini, Stefano and Coppey-Moisan, Maite and Ferrari, Enrico and Garbin, Valeria and Altissimo, Matteo (2004) Microscopy of biological sample through advanced diffractive optics from visible to x-ray wavelength regime. Microscopy Research and Technique, 65 (4/5). pp. 252-262. ISSN 1059-910X

Full content URL: http://onlinelibrary.wiley.com/doi/10.1002/jemt.20...

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Abstract

The aim of this report is to demonstrate a unified version of microscopy through the use of advanced diffractive optics. The unified scheme derives from the technical possibility of realizing front wave engineering in a wide range of electromagnetic spectrum. The unified treatment is realized through the design and nanofabrication of phase diffractive elements (PDE) through which wave front beam shaping is obtained. In particular, we will show applications, by using biological samples, ranging from micromanipulation using optical tweezers to X-ray differential interference contrast (DIC) microscopy combined with X-ray fluorescence. We report some details on the design and physical implementation of diffractive elements that besides focusing also perform other optical functions: beam splitting, beam intensity, and phase redistribution or mode conversion. Laser beam splitting is used for multiple trapping and independent manipulation of micro-beads surrounding a cell as an array of tweezers and for arraying and sorting microscopic size biological samples. Another application is the Gauss to Laguerre-Gauss mode conversion, which allows for trapping and transfering orbital angular momentum of light to micro-particles immersed in a fluid. These experiments are performed in an inverted optical microscope coupled with an infrared laser beam and a spatial light modulator for diffractive optics implementation. High-resolution optics, fabricated by means of e-beam lithography, are demonstrated to control the intensity and the phase of the sheared beams in x-ray DIC microscopy. DIC experiments with phase objects reveal a dramatic increase in image contrast compared to bright-field x-ray microscopy. Besides the topographic information, fluorescence allows detection of certain chemical elements (Cl, P, Sc, K) in the same setup, by changing the photon energy of the x-ray beam.

Keywords:optical trapping, diffractive optics, wave front engineering, phase contrast, scanning microscopy, chemical map
Subjects:F Physical Sciences > F360 Optical Physics
F Physical Sciences > F310 Applied Physics
F Physical Sciences > F361 Laser Physics
Divisions:College of Science > School of Life Sciences
ID Code:8384
Deposited On:28 Mar 2013 19:16

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