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Journal ArticleDOI

High speed sub-micrometric microscopy using optical polymer microlens

01 Oct 2009-Chinese Optics Letters (Chinese Optical Society)-Vol. 7, Iss: 10, pp 901-903

AbstractWe report the high speed scanning submicronic microscopy (SSM) using a low cost polymer microlens integrated at the extremity of an optical fiber. These microlenses are fabricated by a free-radical photopolymerization method. Using a polymer microlens with a radius of curvature of 250 nm, a sub-micrometric gold pattern is imaged experimentally by SSM. Different distances between the tip and the sample are used with a high scanning speed of 200 cm/s. In particular, metallic absorption contrasts are described with an optical spatial resolution of 250 nm at the wavelength of 532 nm. Moreover, finite-difference time-domain (FDTD) simulations concerning the focal lengths of microlenses with different geometries and heights support the experimental data.

Topics: Microlens (59%), Radius of curvature (optics) (53%), Microscopy (52%), Focal length (52%), Optical fiber (51%)

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Journal ArticleDOI
TL;DR: The miniaturized, integrated design opens a range of exciting experimental possibilities, including the dosing of tissue slices, targeted drug delivery, and targeted gene therapy in vivo.
Abstract: Optical transfection is a promising technique for the delivery of foreign genetic material into cells by transiently changing the permeability of the cell membrane. Of the different optical light sources that have been used, femtosecond laser based transfection has been one of the most effective methods for optical transfection which is generally implemented using a free space bulk optical setup. In conventional optical transfection methods the foreign genetic material to be transfected is homogenously mixed in the medium. Here we report the first realization of an integrated optical transfection system which can achieve transfection along with localized drug delivery by combining a microlens fiber based optical transfection system with a micro-capillary based microfluidic system. A fiber based illumination system is also incorporated in the system in order to achieve visual identification of the cell boundaries during transfection. A novel fabrication method is devised to obtain easy and inexpensive fabrication of microlensed fibers, which can be used for femtosecond optical transfection. This fabrication method offers the flexibility to fabricate a microlens which can focus ultra-short laser pulses at a near infrared wavelength to a small focal spot (~3 µm) whilst keeping a relatively large working distance (~20 µm). The transfection efficiency of the integrated system with localized plasmid DNA delivery, is approximately 50%, and is therefore comparable to that of a standard free space transfection system. Also the use of integrated system for localized gene delivery resulted in a reduction of the required amount of DNA for transfection. The miniaturized, integrated design opens a range of exciting experimental possibilities, including the dosing of tissue slices, targeted drug delivery, and targeted gene therapy in vivo.

32 citations



Journal ArticleDOI
TL;DR: The ability to manufacture a reference tapered fiber lens with high symmetry at sub-wavelength scale with a wide range of geometry control is demonstrated, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius on the endface of a single mode fiber.
Abstract: In numerous applications of optical scanning microscopy, a reference tapered fiber lens with high symmetry at sub-wavelength scale remains a challenge. Here, we demonstrate the ability to manufacture it with a wide range of geometry control, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius from several tens of nanometers to several microns on the endface of a single mode fiber. On this basis, a scanning optical microscope has been developed, which allows for fast characterization of various sub-wavelength tapered fiber lenses. Focal position and depth of microlenses with different geometries have been determined to be ranged from several hundreds of nanometers to several microns. FDTD calculations are consistent with experimental results.

12 citations


Journal ArticleDOI
TL;DR: A novel route to directly integrate an array of microlenses at the extremity of an optical fiber bundle based on photopolymerization at the end of the fiber is presented.
Abstract: We present a novel route to directly integrate an array of microlenses at the extremity of an optical fiber bundle The method is based on photopolymerization at the end of the fiber The method is based on the control of exposure dose and volume of the deposited droplet of photopolymerizable formulation Optical properties of the integrated microlenses are discussed on the basis of FDTD calculations

11 citations


Dissertation
01 Dec 2011
Abstract: ......................................... . .......................................................................... iv Declaration ....................................... ............................................................................. v Acknowledgements ................................................................................................ vi Publications ...................................... .......................................................................... viii Peer reviewed journals ............................ ............................................................. viii Book Chapter ................................................................................................... ix Patents .............................................................................................................. ix Conference Publications ........................... ............................................................. ix List of Abbreviations ............................. ...................................................................... xi Table of

6 citations