[Show abstract][Hide abstract] ABSTRACT: We report on octave-spanning supercontinuum generation under pumping with 1360 nm, 120 fs pulses, in an all-solid, all-normal dispersion photonic crystal fiber. The fiber was drawn from thermally matched oxide soft glasses with a hexagonal lattice 35 µm in diameter, 2.5 µm solid core and pitch of Λ/d = 0.9. The fiber was designed for normal dispersion broadly flattened in the 1200–2800 nm range. Experimentally recorded supercontinuum spectrum covered a 900–1900 nm bandwidth and was reconstructed with good agreement using numerical modeling. To the best of our knowledge, this is the first report of an experimentally demonstrated octave-spanning supercontinuum bandwidth, reaching as far as 1900 nm in the all-normal dispersion regime.
[Show abstract][Hide abstract] ABSTRACT: Two dimensional trapping of multiple particles in an interference pattern has been demonstrated using a four core lensed multicore fiber and a diffractive optical element.
Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2013 Conference on; 01/2013
[Show abstract][Hide abstract] ABSTRACT: We demonstrate the feasibility of using the nanostructured micro-optics technology to create a large diameter quantized elliptical microlens. Nanostructured gradient index elements have discrete internal structure with feature sizes much smaller than the wavelength of the incident light. Standard methods of GRIN microlens fabrication suffer from limited gadient value as well as from limited accuracy of gradient control. The nanostructured micro-optics fabrication technology, which exploits the techniques used in the fabrication of photonic crystal fibre, can be used to create a wide range of nanostructured gradient index micro-optical components. In this paper we demonstrate the feasibility of using the nanostructured micro-optics technology to create a 20–100 μm diameter quantized elliptical and spherical microlens.
[Show abstract][Hide abstract] ABSTRACT: We describe the application of the hot embossing process to fabricate micro-optical elements using multi-component soft glasses. The fabricated elements are both refractive and diffractive and can be used in the visible to mid-infrared range. We will present all steps of the fabrication process and optical properties of obtained elements.
[Show abstract][Hide abstract] ABSTRACT: The exploitation of micro-optical technologies in laser beam shaping and
wavefront manipulation applications has a long and distinguished
history. The functional flexibility of high resolution, allglass phase
only microstructures, combined with their relative immunity to
laser-induced damage mechanisms, allows the creation of arbitrary beam
profiles from a wide range of different laser configurations. In this
paper, we shall review some of the methods used in the design and
fabrication of laser beam shaping and wavefront manipulation
[Show abstract][Hide abstract] ABSTRACT: In this paper we report on the development of diffractive and refractive
micro optical components devoted to MidIR applications. As a material we
use a customized heavy metal oxide glasses with high transmission in the
range 0.6÷6.0μm. Optimization of the glass composition in
four- and five-component oxide systems for a broadband transmission
window is difficult due to their excessive crystallization
susceptibility. Several metals and alloys were tested for their
suitability as a stamping medium. Optimal performance was obtained for
selected brass and steel stamps, as well as for pure silica stamps. As a
technology testboard we have developed 1D and 2D diffractive gratings
with a minimum feature size of 5μm as well as Fresnel microlenses
with a diameter of 200μm. The quality of the embossed elements was
verified by comparison of the master and replicated elements using a
non-contact white light interferometer.
[Show abstract][Hide abstract] ABSTRACT: We present a novel approach to the fabrication of diffractive optical
elements. Unlike traditional diffractive optical elements, the different
phase shifts are obtained through a refractive index variation by using
different types of glass. This approach results in a completely flat
element which is easy to integrate with other optical components. For
fabrication of the test DOE structures we have used the stack-and-draw
technique. This method, which was originally developed for the
fabrication of photonic crystal fibres, has been modified to allow the
fabrication of nanostructured micro-optical components. In this paper we
present the results from proof of concept periodic checkerboards
fabricated on a square and hexagonal lattice with feature sizes of
8μm and 46μm. The components were fabricated from two types of
rods made of the low refractive index silicate glass and the high
refractive index of lead-silicate glass. The measured characteristics of
the fabricated components are presented The influence of
fabrication-induced structure distortions on the optical performance of
the components is discussed.
[Show abstract][Hide abstract] ABSTRACT: We present a detailed examination of the design and expected operation of an artificially birefringent material based around the nanostructured stack-and-draw fabrication technique developed recently. The expected degree of birefringence is estimated using a Finite Difference Time Domain simulation of the physical system and is shown to be in agreement with that predicted by a second order effective medium theory treatment of the nanostructured material. The effects of finite device dimensions are studied and an estimate of the required device thickness for a half-wave retardation is made.
[Show abstract][Hide abstract] ABSTRACT: The subwavelength structure of the core of a photonic crystal fibre can modify its dispersion characteristic and significantly shift the zero dispersion wavelength. The dispersion properties of photonic crystal fibres with core structures made of a 2D lattice of subwavelength air holes and various glass inclusions are studied. We show that a modification of the core structure can give flat dispersion over a range of over 300 nm and can shift the zero dispersion wavelength over 700 nm while the core diameter and photonic cladding remain unchanged. The developed photonic crystal fibre with nanorod core has successfully demonstrated supercontinuum generation in NIR.
J. Europ. Opt. Soc. Rap. Public. 01/2011; 6:11038.
[Show abstract][Hide abstract] ABSTRACT: We present a method that allows accurate simulation of the output intensity of an arbitrary array of intense spots generated by a tiled hologram. In this method zero padding of n times the number of data points in the matrix of the incident laser beam is applied before Fourier transform to fully reveal the speckles and the reconstruction error. The resulting matrix is reduced to a smaller one by resampling at an interval of n. The convolution of a matrix representing the amplitude point spread function of the optical system and the reduced matrix gives the final output amplitude distribution. A wedge target is used as a test image. The experimental results are in excellent agreement with the simulation.
Journal of optics 07/2010; 12(8):085402. · 1.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We show theoretical and experimental characterizations of a nanostructured gradient-index lens. The elliptical lens is a nonguiding element fabricated using the mosaic method, which is widely used for the fabrication of photonic crystal fibers. For the first time we show experimental data in the optics regime that confirm the effective medium approximation for discrete mosaic structures with subwavelength feature size. This opens the door for the development of general asymmetric gradient-index materials.
[Show abstract][Hide abstract] ABSTRACT: In this paper nano-structured elements are fabricated with the stack-and-draw method used for all solid photonic crystal fibres. We fabricate non-guiding structures with a much larger diameter and feature sizes of 200 nm and less. These structures are cut to discs of a few hundred mum thickness for use as optical GRIN elements like lenses and beam correctors. Due to the method of fabrication, the elements can have a completely arbitrary index distribution within the limitations of the materials used in the element fabrication.
Lasers and Electro-Optics 2009 and the European Quantum Electronics Conference. CLEO Europe - EQEC 2009. European Conference on; 07/2009
[Show abstract][Hide abstract] ABSTRACT: We present a novel fabrication technology for nano-structured graded index micro-optical components, based on the stack-and-draw method used for photonic crystal fibres. These discrete structures can be described with an effective refractive index distribution. Furthermore we present spherical nano-structured microlenses with a flat facet fabricated with this method and designed using an algorithm based on the Maxwell-Garnett mixing formula. Finally we show theoretical verification by using FDTD simulations for a nano-structured lens as well as experimental data obtained in the microwave regime.
[Show abstract][Hide abstract] ABSTRACT: The use of nano-structured elements in the fabrication of micro-optical subwavelength components requires a fully vectorial solution to Maxwell's curl equations. In this paper, we compare the results generated by two of the main methods used in the solution of the curl equations, the Fourier Modal Method (FMM) and the Finite Difference Time Domain (FDTD) method. We address the computational issues surrounding the accurate modelling of nano-structured elements (with features in the 10nm-100nm range) for a range of micro-optical elements, e.g. cylindrical lenses, photonic bandgap reflectors and polarisation dependent beamsplitters. Finally, we show the experimental verification of the nano-structured designs using microwave radiation.