Search results for "Optoelectronics"
showing 10 items of 2306 documents
Monolithic integration of Giant Magnetoresistance (GMR) devices onto standard processed CMOS dies
2014
Giant Magnetoresistance (GMR) based technology is nowadays the preferred option for low magnetic fields sensing in disciplines such as biotechnology or microelectronics. Their compatibility with standard CMOS processes is currently investigated as a key point for the development of novel applications, requiring compact electronic readout. In this paper, such compatibility has been experimentally studied with two particular non-dedicated CMOS standards: 0.35 μm from AMS (Austria MicroSystems) and 2.5 μm from CNM (Centre Nacional de Microelectrònica, Barcelona) as representative examples. GMR test devices have been designed and fabricated onto processed chips from both technologies. In order …
Dispersion-optimized multicladding silicon nitride waveguides for nonlinear frequency generation from ultraviolet to mid-infrared
2016
Nonlinear frequency conversion spanning from the ultraviolet to the mid-infrared (beyond 2.4 μm) is experimentally demonstrated in multicladding silicon nitride (𝑆𝑖𝑋𝑁𝑌) waveguides. By adjusting the waveguide cross-section the chromatic dispersion is flattened, which enhances both the efficiency and the bandwidth of the nonlinear conversion. How accurately the dispersion is tailored is assessed through chromatic dispersion measurements and an experiment/simulation comparison of the dispersive waves' wavelength locations. Undesirable fluctuations of both the refractive index and the dimensions of the waveguide during the fabrication process result in a dispersion unpredictability of at l…
Molecular semiconductor-doped insulator (MSDI) heterojunctions: Oligothiophene/bisphtalocyanine (LuPc2) and perylene/bisphthalocyanine as new structu…
2010
Abstract The combination of a sexithiophene and a perylene diimide derivatives, as p-type and n-type materials, respectively, used as sub-layers, to an intrinsic semiconductor, namely the lutetium bisphthalocyanine, allows to obtain a new transducer for gas sensing. These transducers were called molecular semiconductor-doped insulator (MSDI) heterojunctions, were recently designed and reported, but with only phthalocyanines as active materials. p-Type material leads to MSDIs that exhibit a positive response to ozone and a negative response to ammonia, whereas MSDIs prepared from n-type material exhibit a positive response to ammonia and negative response to ozone. The remarkable point is th…
Luminescence properties of KNbO3 crystals
1997
Thermostimulated luminescence, X-ray-induced luminescence, photostimulated luminescence as well as the time-resolved luminescence and absorption after pulsed electron beam irradiation were studied in KNbO3 crystals at 80–400 K. A correlation between defects causing the luminescence and blue-light-induced IR absorption effects supressing the second harmonic generation efficiency in KNbO3 is discussed.
Nonlinear optical properties of silver nanoparticles: separating thermo-optical and Kerr effects
2021
In this paper, we present a study on thermo-optical effect in core-shell silver/thiol-termination ligand nanoparticles. Nanoparticles were dissolved in Dichloromethane. Experimental measurements were carried out using a Z-scan setup. As laser sources we used two 1064 nm lasers: i) 28 ps pulse width laser with 1000 Hz pulse repetition rate; ii) 8 ns pulse width laser with changeable pulse repetition rate 200 – 40 000 Hz. To study what processes lead to refractive index changes we used the polarization-resolved Z-scan method. Comparing ps and ns results showed that response time of single pulse thermal effects for organic solvents depends on beam size while for nanoparticles it corresponds to…
How does an In-containing underlayer prevent the propagation of defects in InGaN QW LEDs?: identification of SRH centers and modeling of trap profile
2021
Recent reports indicated that the use of an InAlN underlayer (UL) can significantly improve the efficiency of InGaN/GaN quantum well (QW) LEDs. Currently, this result is explained by considering that the UL reduces the density of nonradiative recombination centers in the QWs. However, an experimental proof of the reduction of defects in the QWs is not straightforward. In this paper, we use combined electrical (I-V), optical (L-I), capacitance (C-V), steady-state photocapacitance (SSPC) and light-assisted capacitance-voltage (LCV) measurements to explain why devices with UL have a much higher efficiency than identical LEDs without UL. Specifically, we demonstrated an improvement in both elec…
The manipulation of ions using electromagnetic traps
1992
Electromagnetic traps, in addition to providing very clean and gentle confinement for very precise and sensitive observation of charged particles, are very versatile devices for collecting and preparing charged particles from outside sources for observation by devices which are also outside, devices which may in themselves be other electromagnetic traps. This paper introduces the basic principles of using electromagnetic traps for collecting and cooling and presents some preliminary test results from using Paul traps for these purposes. Specifically, in relatively modest Paul traps with 28 mm between end electrodes a collection efficiency of 0.2% was achieved for a 60 keV DC beam of 132Xe i…
Continuously tunable diamond Raman laser for resonance ionization experiments at CERN
2019
We demonstrate a highly efficient, continuously tunable, diamond Raman laser operating in the blue region of the spectrum. The linewidth and tunability characteristics of a frequency-doubled Ti:Sapphire laser were transferred directly to the Stokes output, offering great potential for spectroscopic applications using an all-solid-state platform.
SIMULATION OF THERMAL EFFECTS IN OPTOELECTRONIC DEVICES USING COUPLED ENERGY-TRANSPORT AND CIRCUIT MODELS
2008
A coupled model with optoelectronic semiconductor devices in electric circuits is proposed. The circuit is modeled by differential-algebraic equations derived from modified nodal analysis. The transport of charge carriers in the semiconductor devices (laser diode and photo diode) is described by the energy-transport equations for the electron density and temperature, the drift-diffusion equations for the hole density, and the Poisson equation for the electric potential. The generation of photons in the laser diode is modeled by spontaneous and stimulated recombination terms appearing in the transport equations. The devices are coupled to the circuit by the semiconductor current entering the…
1.65-μm Er:Yb:YAG diode-pumped laser delivering 80-mJ pulse energy
2005
We demonstrate efficient lasing of bulk diode-pumped Er 31 :Yb 31 :YAG at 1.645 mm. The material is transversely pumped using three quasi-cw 960-nm laser diode arrays in a simple arrangement. In the free-running mode of operation, an output pulse energy of 79 mJ is obtained at 4.7 J of incident optical pump energy. The lasing threshold lies in the range 1.0 to 1.9 J in long-pulse operation, depending on pumping conditions, and optical slope efficiencies of 2.2% to 3.4% were measured with respect to the incident pump energy. Furthermore, initial Q-switching experiments with a Co:MALO saturable absorber yielded pulses of 1.7-mJ energy and 340-ns FWHM duration. As the reported laser setup also…