Search results for "optoelectronic"
showing 10 items of 2328 documents
Multi-level optimization of a fiber transmission system via nonlinearity management
2006
Nonlinearity management is explored as a complete tool to obtain maximum transmission reach in a WDM fiber transmission system, making it possible to optimize multiple system parameters, including optimal dispersion pre-compensation, with fast simulations based on the continuous-wave approximation. © 2006 Optical Society of America.
An Optical Remote Sensor for Fingerprint Identification using Speckle Pattern
2017
The implementation of a simple, inexpensive optical device for remote fingerprint identification is presented. The sensor is based on temporal tracking of back-reflected secondary speckle patterns generated while illuminating a finger with a laser.
Multilevel system optimisation via nonlinearity management
2006
Nonlinearity management is explored as a multilevel tool to obtain maximum transmission reach in a WDM system. A technique for the fast calculation of the optimal dispersion pre-compensation in systems with distributed amplification is proposed.
Optical and dielectric properties of MoO 3 nanosheets for van der Waals heterostructures
2021
Two-dimensional (2D) insulators are a key element in the design and fabrication of van der Waals heterostructures. They are vital as transparent dielectric spacers whose thickness can influence both the photonic, electronic, and optoelectronic properties of 2D devices. Simultaneously, they provide protection of the active layers in the heterostructure. For these critical roles, hexagonal Boron Nitride (hBN) is the dominant choice due to its large bandgap, atomic flatness, low defect density, and encapsulation properties. However, the broad catalogue of 2D insulators offers exciting opportunities to replace hBN in certain applications that require transparent thin layers with additional opti…
UV-Photoinduced Defects In Ge-Doped Optical Fibers
2005
We investigated the effect of continuous-wave (cw) UV laser radiation on single-mode Ge-doped H2- loaded optical fibers. An innovative technique was developed to measure the optical absorption (OA) induced in the samples by irradiation, and to study its dependence from laser fluence. The combined use of the electron spin resonance (ESR) technique allowed the structural identification of several radiation-induced point defects, among which the Ge(1) (GeO4 -) is found to be responsible of induced OA in the investigated spectral region.
Enhanced Reflectivity Change and Phase Shift of Polarized Light: Double Parameter Multilayer Sensor
2022
Herein, the concept of point of darkness based on polarized light phase difference and absorption of light is demonstrated by simulations using low refractive index and extinction coefficient semiconductor and dielectric, and high refractive index nonoxidizing metal multilayer thin film structures. Several multilayer sensor configurations show great sensitivity to thickness and refractive index variation of the detectable material by measuring the reflectivity ratio {\Psi} and phase shift {\Delta}. Focus is on such multilayers, which have sensitivity to both parameters ({\Psi}, {\Delta}) in the visible spectral range, thus opening the possibility for further research on a new biomedical sen…
Patterning and tuning of electrical and optical properties of graphene by laser induced two-photon oxidation
2015
Graphene, being an ultrathin, durable, flexible, transparent material with superior conductivity and unusual optical properties, promises many novel applications in electronics, photonics and optoelectronics. For applications in electronics, patterning and modification of electrical properties is very desirable since pristine graphene has no band gap. Here we demonstrate a simple all-optical patterning method for graphene, based on laser induced two-photon oxidation. By tuning the intensity of irradiation and the number of pulses the level of oxidation can be controlled to high precision and, therefore, a band gap can be introduced and electrical and optical properties can be continuously t…
Design of a compact diode laser system for dual-species atom interferometry with rubidium and potassium in space
2017
We report on a micro-integrated high power diode laser based system for the MAIUS II/III missions. The laser system features fiber coupled and frequency stabilized external cavity diode lasers (ECDL) for laser cooling, Bose-Einstein condensate (BEC) generation and dual species atom interferometry with rubidium and potassium on board a sounding rocket.
Blue luminescence in ZnO single crystals, nanopowders, ceramic
2007
The luminescence spectra and luminescence decay processes were studied in a ZnO single crystal, nanopowders and ceramic at liquid helium and room temperature under VUV synchrotron radiation as well as under pulsed laser excitation. The exciton-exciton and exciton-multiphonon processes were compared in different ZnO nanopowders (commercial powder, powders obtained by vaporization-condensation technique) and ceramic. The possibility of luminescence decay time modification by Al3+ doping was shown.
Influence of the excitation conditions on the emission behavior of carbon nanodot-based planar microcavities
2020
The authors investigate the influence of the pulse length as well as the repetition rate of the optical excitation on the emission behavior of carbon-nanodot-based planar microcavities.