A5101966023- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Chalcogenide Semiconductor Thin Films
- Combustion and flame dynamics
- Quantum Dots Synthesis And Properties
- Molecular Junctions and Nanostructures
- Advanced Fiber Laser Technologies
- Advanced Sensor Technologies Research
- Advanced Combustion Engine Technologies
- Copper-based nanomaterials and applications
- Laser Design and Applications
- Advanced MEMS and NEMS Technologies
- Gas Dynamics and Kinetic Theory
- Advanced DC-DC Converters
- Nonlinear Dynamics and Pattern Formation
- Optical Network Technologies
- Computational Fluid Dynamics and Aerodynamics
- Spectroscopy and Laser Applications
- Laser-induced spectroscopy and plasma
- Mechanical Circulatory Support Devices
- Semiconductor materials and interfaces
- Advancements in Photolithography Techniques
- Multilevel Inverters and Converters
- Aerodynamics and Acoustics in Jet Flows
The Ohio State University
2020-2024
Philips (Germany)
2009-2019
Philips (Netherlands)
2015
NXP (Netherlands)
2015
Philips (United States)
2008-2013
Philips (United Kingdom)
2013
Philips (Finland)
2002-2012
Universität Ulm
1996-2005
Philips (Belgium)
2005
Synopsys (United States)
2004
We report on vertical-cavity surface-emitting lasers (VCSELs) and laser arrays providing high output powers in the 980-nm wavelength regime. Extensive investigations size scaling behavior of single top- bottom-emitting devices concerning fundamental electrooptical thermal properties show limits attainable characteristics. Maximum experimentally achieved continuous-wave (CW) optical at room temperature are 180 350 mW for VCSELs, respectively. Detailed analysis interaction between closely...
Bottom-emitting vertical-cavity surface-emitting InGaAs MQW lasers operating in the 980-nm wavelength regime have been designed for high continuous-wave optical output power. Devices of 200-μm active diameter and optimized performance reach 350-mW maximum power when mounted on a heat sink. 50-μm-size produce 100 mW at 25% electrical to conversion efficiency. Thermal properties size dependent basic characteristics are investigated detail.
Easy system design, compactness and a uniform power distribution define the basic advantages of high VCSEL systems. Full addressability in space time add new dimensions for optimization enable "digital photonic production". Many thermal processes benefit from improved control i.e. heat is applied exactly where when it needed. The compact systems can be integrated into most manufacturing equipment, replacing batch using large furnaces reducing energy consumption. This paper will present how...
The intention of this paper is to report on state-of-the-art high-power vertical-cavity surface-emitting laser diodes (VCSELs), single devices as well two-dimensional (2-D) arrays. Both approaches are studied in terms electrooptical characteristics, beam performance, and scaling behavior. maximum continuous wave (CW) output power at room temperature large-area bottom-emitting with active diameters up 320 /spl mu/m high 0.89 W, which our knowledge the highest value reported for a device....
Acoustic droplet ejection (ADE) gently and precisely aliquots nanoliter picoliter liquid volumes without any physical contact with the solution being transferred. The technology is very automation-friendly, as it compatible conventional microplates. Focused energy from an acoustic transducer induces into inverted standard microplate. commercial system transfers low-nanoliter of dimethyl sulfoxide–dissolved compound libraries thereby enables cell-based assays to be performed in 1536-well plates.
We describe several diode laser-based instruments that can detect important species in chemical oxygen iodine lasers (COIL). Species detected include: water vapor, atomic iodine, and ground state oxygen. The sensors allow non-intrusive, real-time measurements from which one determine small signal gain the singlet delta yield. vapor concentrations also be continuously monitored. sensitivities of are sufficient for all conditions found typical COIL devices. room temperature miniature fiber...
Experiments were conducted to investigate the effect of compressibility on turbulent reacting mixing layers with moderate heat release. Side- and plan-view visualizations layers, which formed between a high-speed high-temperature vitiated-air stream low-speed ambient-temperature hydrogen stream, obtained using combined OH/acetone planar laser-induced fluorescence imaging technique. The instantaneous images OH provide two-dimensional maps regions combustion, similar acetone, was seeded into...
Selectively oxidized InGaAs vertical-cavity surface emitting lasers (VCSELs) at an emission wavelength of /spl lambda/=980 mm are investigated for high-power applications. Densely packed arrays consisting 19 single devices with active diameter 50 μm emit 1.08 W continuous-wave (CW) optical output power room temperature. At 10/spl deg/C, heat sink temperature the increases to 1.4 W, which corresponds a chip size averaged density 1 kW/spl middot/cm <sup...
The 1.24 eV bandgap, 18.8% power conversion efficiency Ag‐alloyed chalcopyrite (Ag,Cu)(In,Ga)Se 2 (ACIGS) solar cells are characterized to relate voltage and improvements electro‐optical (EO) characteristics. Shockley–Read–Hall recombination center defect density, identified through deep level transient spectroscopy time‐resolved photoluminescence (TRPL), is reduced potassium copper treatment optimization. Concomitantly, longer minority carrier lifetimes achieved, which increases...
The spatial mode structure of circular broad-area bottom-emitting vertical-cavity surface-emitting lasers is investigated close to threshold. devices display very high-order flower-like Laguerre modes as well structures with a Cartesian symmetry in spite the original O(2) symmetry. In some cases latter resemble tilted waves more than Hermite-Gaussian modes. Spatial appear for both sides detuning between gain peak and cavity resonance. results indicate necessity refine theoretical models...
Single phase uninterruptible power supplies (UPS) employ an inverter for DC to AC conversion. Advanced inverters consist of a full bridge transistor topology and LC filter. An optimal performance can be achieved if the output voltage is controlled by unipolar pulse width modulation (PWM). The paper describes influence PWM on voltages current within inverter. Both frequency domain time are used evaluate most important harmonics as well peak RMS values ripple. This results in general equations...
Modelocked optically pumped vertical external cavity surface emitting lasers (VECSELs) have generated up to 6.4-W average power, which is higher than for any other semiconductor lasers. Electrical pumping of modelocked VECSELs the next step toward a level integration. With continuous wave (cw) electrically (EP) VECSELs, an output power 900 mW has been demonstrated from undisclosed proprietary novalux extended laser (NECSEL) design. In contrast, NECSELs only at 40 mW. Recently, we presented...
We investigate the spatial structure of broad-area vertical-cavity regenerative amplifiers injected with a homogeneous beam. The emerging patterns have predominantly sixfold rotational symmetry, verifying recent prediction formation hexagons. length scale is controllable by means detuning and follows for tilted waves.
Voltage losses reduce the photovoltaic conversion efficiency of thin‐film solar cells and are a primary limitation in Cu(In,Ga)Se 2 . Herein, voltage loss analysis fabricated at three institutions with variation process, bandgap, absorber structure, postdeposition treatment (PDT), is presented. Nonradiative due to Shockley–Read–Hall charge carrier recombination dominate constitute >75% total compared <25% from radiative losses. The results nonideal absorption carriers band tails that...
VCSEL arrays are the ideal light source for 3D imaging applications. The narrow emission spectrum and ability short pulses make them superior to LEDs. Combined with fast photodiodes or special camera chips spatial information can be obtained which is needed in diverse applications like autofocus, indoor navigation, 3D-object recognition, augmented reality autonomously driving vehicles. Pulse operation at ns scale low duty cycle work significantly higher current than traditionally used VCSELs...
Thermal treatment may be by far the most frequent process used in manufacturing, but only at a few places lasers could make an inroad. For thermal treatment, homogeneous illumination of large areas lower brightness, and accurate temporal as well spatial control power is required. This complicated for conventional high-power lasers, while vertical-cavity surface emitting laser-diode (VCSEL) arrays inherently have these capabilities. Because their fast switching capability low dissipation,...
Large area MBE grown vertical-cavity surface emitting laser diodes (VCSELs) for high power emission at ~980 nm wavelength have been fabricated. Top devices of 146 µm active diameter deliver 160 mW 20% wallplug efficiency and 180 maximum output in a junction-up configuration.
We compare various approaches aiming at large-area high-power single-mode oxidized VCSELs. Stable and reproducible emission with SMSR (side-mode suppression ratio) greater than 30dB output powers well above 5mW are reported for the long monolithic cavity self-aligned shallow surface etching approaches, both of which suitable commercial production. Additionally, Photonic Crystal Surface-Emitting Lasers (PCSELs) introduced, enable advanced mode control by novel transverse optical guiding techniques.