The generations of photonic jet array using rectangle phase diffraction grating at visible light region are demonstrated numerically and experimentally for the first time. The power flow patterns for the rectangle diffraction grating are simulated by using the finite-difference time-domain method. In experiment, the rectangle phase diffraction grating was fabricated with polydimethylsiloxane material. The direct imaging of the spatial and amplitude features for the gratingassisted photonic jet array is performed with a scanning optical microscope system. The focusing qualities of photonic jet array are evaluated in terms of focal length and transversal width along propagation and transversal directions. The photonic jet array could be operated in a wide range application for nanotechnology, self-assembly, energy generation and storage materials through the rectangle phase diffraction grating.
Proc. SPIE. 10242, Integrated Optics: Physics and Simulations III
KEYWORDS: Diffraction, Refractive index, Visible radiation, Surface plasmon polaritons, Finite-difference time-domain method, Super resolution, Photon polarization, Dielectrics, 3D modeling, Near field, Range imaging, Near field optics, Photonic nanostructures, Diffraction gratings
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The generation of linear photonic nanojet using core-shell optical microfiber is demonstrated numerically and experimentally in the visible light region. The power flow patterns for the core-shell optical microfiber are calculated by using the finite-difference time-domain method. The focusing properties of linear photonic nanojet are evaluated in terms of length and width along propagation and transversal directions. In experiment, the silica optical fiber is etched chemically down to 6 μm diameter and coated with metallic thin film by using glancing angle deposition. We show that the linear photonic nanojet is enhanced clearly by metallic shell due to surface plasmon polaritons. The large-area superresolution imaging can be performed by using a core-shell optical microfiber in the far-field system. The potential applications of this core-shell optical microfiber include micro-fluidics and nano-structure measurements.
Digital fringe projection techniques have been widely studied in industrial applications because of the advantages of high accuracy, fast acquisition and non-contact operation. In this study, a single-shot high-speed digital color fringe projection technique is proposed to measure three-dimensional (3-D) facial features. The light source used in the measurement system is structured light with color fringe patterns. A projector with digital light processing is used as light source to project color structured light onto face. The distorted fringe pattern image is captured by the 3-CCD color camera and encoded into red, green and blue channels. The phase-shifting algorithm and quality guided path unwrapping algorithm are used to calculate absolute phase map. The detecting angle of the color camera is adjusted by using a motorized stage. Finally, a complete 3-D facial feature is obtained by our technique. We have successfully achieved simultaneous 3-D phase acquisition, reconstruction and exhibition at a speed of 0.5 s. The experimental results may provide a novel, high accuracy and real-time 3-D shape measurement for facial recognition system.
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