Search results for "ELECTRONICS"
showing 10 items of 4340 documents
Surface Plasmons for Chiral Sensing
2021
Chiral sensitive techniques have been used to probe the fundamental symmetries of the universe, study biomolecular structures, and even develop safe drugs. The traditional method for the measurement of chirality is through optical activity, however, chiroptical signals are inherently weak and often suppressed by large backgrounds. Different techniques have been proposed to overcome the limitations of traditionally used optical polarimetry, such as cavity- and/or nanophotonic-based schemes. In this chapter we demonstrate how surface plasmon resonance can be employed as a new research tool for chiral sensing, which we term here as CHIral Surface Plasmon Resonance (CHISPR). We present how surf…
Multidimensional optical sensing and imaging for displays, computational imaging, optical security, and healthcare
2016
In this invited paper, we present an overview of our recently published work on 3D imaging, visualization and displays, including optical security using quantum imaging principles, 3D microscopy, healthcare, automated disease identification with 3D imaging, fatigue free augmented reality 3D glasses, and optical security and authentication using photon counting for IC inspection, polarimetric photon counting 3D imaging, and 3D human gesture recognition
Compact all-diffractive setup for spectral synthesis with non-uniform illumination
2009
Optical filters based on diffractive optical elements (DOE) have received increased attention since the development of the first synthetic spectrum as a tool for correlation spectroscopy [1]. The production of a synthetic spectrum requires the design of a DOE that transforms the spectrum associated with the incident light into the spectrum of interest. Based on this procedure, several approaches have been reported in the literature [1–4]. In general, these configurations employ angular dispersion elements for spectrum tailoring, so they are restricted to working off-axis, and most of them need an extra focusing refractive lens.
Non-destructive single-pass low-noise detection of ions in a beamline.
2015
We have conceived, built, and operated a device for the non-destructive single-pass detection of charged particles in a beamline. The detector is based on the non-resonant pick-up and subsequent low-noise amplification of the image charges induced in a cylindrical electrode surrounding the particles' beam path. The first stage of the amplification electronics is designed to be operated from room temperature down to liquid helium temperature. The device represents a non-destructive charge counter as well as a sensitive timing circuit. We present the concept and design details of the device. We have characterized its performance and show measurements with low-energy highly charged ions (such …
Spatial Solitons in Quadratic 2D Nonlinear Photonic Crystals
2007
We report on the first investigations into parametric solitary-wave formation in 2D nonlinear photonic crystals and present experimental results obtained in an hexagonally poled LiNbO3 waveguide designed for twin-beam second harmonic generation at telecom wavelengths.
Monte Carlo Analysis of Voltage-Current Characteristic Nonlinearity and Harmonic Generation in Submicron Semiconductor Structures
2006
Using a multiparticles Monte Carlo technique, we investigate the dependence of the nonlinear carrier dynamics in GaAs n+nn+ structures operating under very intense sub-terahertz signals from some process parameters as: i) the frequency and the intensity of the excitation signal and ii) the length of the n region
Stimulated Emission in InGaN/GaN Multiple Quantum Wells with Different Indium Content
2005
1. IntroductionLight-emitting and laser diodes for the green to near-UV region are basedon quantum structures with the InGaN active region [1]. The indium contentin the wells is a technological parameter that provides a straightforward accessfor the change in the color of the light-emitting device. However, the redshift ofthe emission peak with increase in indium content is caused not only by a simplealloying, but also by carrier localization due to difierence in In and Ga atomic
Multi-illumination single-holographic-exposure lensless Fresnel (MISHELF) microscopy using 4 channels
2021
MISHELF microscopy is generalized by considering 4 illumination/detection channels while retaining single-shot working principle, twin image mitigation and noise averaging. Proof of principle validation is included considering a resolution test target.
Comparative analysis of spectral coherence in microresonator frequency combs
2014
Microresonator combs exploit parametric oscillation and nonlinear mixing in an ultrahigh-Q cavity. This new comb generator offers unique potential for chip integration and access to high repetition rates. However, time-domain studies reveal an intricate spectral coherence behavior in this type of platform. In particular, coherent, partially coherent or incoherent combs have been observed using the same microresonator under different pumping conditions. In this work, we provide a numerical analysis of the coherence dynamics that supports the above experimental findings and verify particular design rules to achieve spectrally coherent microresonator combs. A particular emphasis is placed in u…
Preliminary radiation hardness tests of single photon Si detectors
2010
Single photon Si detectors were fabricated by STMicroelectronics and fully characterized in standard operation conditions and after irradiations. Both single cells and arrays, of dimensions ranging from 5x5 up to 64x64, were electrically tested. The devices operation was studied as a function of the temperature from -25 degrees C to 65 degrees C varying the voltage over breakdown, from 5% up to 20% of the breakdown voltage before and after irradiation using both light ions, 10 MeV B ions to doses in the range 3x10(7)-5x10(10) cm(-2), and X-rays irradiations in the range 0.5-20 krad(Si). Optical characterization was performed using a laser at 659 nm and opportunely chosen filters to vary the…