A Deep Ultraviolet Laser Light Source By Frequency Doubling Of Gan Based External Cavity Diode Laser Radiation
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A Deep Ultraviolet Laser Light Source By Frequency Doubling Of Gan Based External Cavity Diode Laser Radiation
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Author : Norman Ruhnke
language : en
Publisher: Cuvillier Verlag
Release Date : 2022-05-13
A Deep Ultraviolet Laser Light Source By Frequency Doubling Of Gan Based External Cavity Diode Laser Radiation written by Norman Ruhnke and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-05-13 with Technology & Engineering categories.
A compact and portable laser light source emitting in the wavelength range between 210 nm and 230 nm would enable numerous applications outside of laboratory environments, such as sterilization and disinfection of medical equipment, water purification or gas and air analysis using absorption spectroscopy. Such a source is also highly attractive for the identification and quantification of proteins and biomolecules by means of laser-induced fluorescence or Raman spectroscopy. In this thesis, a novel concept to realize such a compact and portable laser light source with low power consumption and an emission around 222 nm is investigated. The developed concept is based on single-pass frequency doubling of a commercially available high-power GaN laser diode emitting in the blue spectral range. Due to the low frequency doubling conversion efficiencies in this wavelength range of about 10-4 W-1, a laser diode with high optical output power above 1 W is required as pump source. Moreover, it has to exhibit narrowband emission in the range of the acceptance bandwidth of the applied nonlinear BBO crystal. Since GaN-based high-power laser diodes typically show broad emission spectra of Δλ = 1…2 nm, stabilizing and narrowing their wavelength by using external wavelength-selective elements is investigated and presented for the first time. With the understanding for the novel concept gained in this work, a compact ultraviolet laser light source was realized. It has a power consumption of less than 10 W and is exceptionally robust due to its immoveable components. The demonstrated output power of 160 μW enables numerous industrial and everyday applications for which previous laser systems have been too complex and overly cost- and energy-intensive.
Short Channel Gan Fet Mmic Technology For High Reliability Applications Band 74
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Author : Konstantin Osipov
language : en
Publisher: Cuvillier Verlag
Release Date : 2024-02-07
Short Channel Gan Fet Mmic Technology For High Reliability Applications Band 74 written by Konstantin Osipov and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-02-07 with categories.
Nowdays GaN HEMT technology reached maturity level that allows industral fabrication of such devices for wide range of civil (telecommunications, power electrinics, automotive etc.), as well as space and military (phased array radars) applications. At this level, technology start reaching physical limits of GaN material and require new approaches that will allow to overcome some of well known problems related to GaN HEMTs, such as high gate leakage currents, reliability issues and difficulties of normally-off transistor fabrication. The goal of these theses is theoretical and experimental confirmation of the idea, that using peizoelectric nature of GaN crystal will allow local modification of GaN HEMT channel by means of external mechanical stress (using first and second passivation layers as stressors). After implementation of the proposed technology changes and new device geometry in process flow intended for 150 nm GaN HEMTMMIC fabrication, E/D devices with pinch-off voltages +0.1V and -1.65V respectively were fabricated on the same wafer within single process flow. It was observed, that E-mode devices, fabricated using compressed passivation layers, demonstrate lower gate leakage currents and more robust in HTRB test as compared to D-mode devices. In summary, it was demonstrated, that it is possible to control pinch-off voltage and gate leakage current of short channel GaN HEMTs by application of external stress. Usage of external stress, opens new degree of freedom in device optimization, and extends opportunities for more advanced MMIC design.
Design Simulation And Analysis Of Laterally Longitudinally Non Uniform Edge Emitting Gaas Based Diode Lasers Band 73
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Author : Jan-Philipp Koester
language : en
Publisher: Cuvillier Verlag
Release Date : 2023-09-19
Design Simulation And Analysis Of Laterally Longitudinally Non Uniform Edge Emitting Gaas Based Diode Lasers Band 73 written by Jan-Philipp Koester and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-09-19 with categories.
Edge-emitting quantum-well diode lasers based on GaAs combine a high conversion efficiency, a wide range of emission wavelengths covering a span from 630 nm to 1180 nm, and the ability to achieve high output powers. The often used longitudinal-invariant Fabry-Pérot-type resonators are easy to design but often lead to functionality or performance limitations. In this work, the application of laterally-longitudinally non-uniform resonator configurations is explored as a way to reduce unwanted and performance-limiting effects. The investigations are carried out on existing and entirely newly developed laser designs using dedicated simulation tools. These include a sophisticated time-dependent laser simulator based on a traveling-wave model of the optical fields in the lateral-longitudinal plane and a Maxwell solver based on the eigenmode expansion method for the simulation of passive waveguides. Whenever possible, the simulation results are compared with experimental data. Based on this approach, three fundamentally different laser types are investigated: • Dual-wavelength lasers emitting two slightly detuned wavelengths around 784 nm out of a single aperture • Ridge-waveguide lasers with tapered waveguide and contact layouts that emit light of a wavelength of around 970 nm • Broad-area lasers with slightly tapered contact layouts emitting at 910 nm The results of this thesis underline the potential of lateral-longitudinal non-uniform laser designs to increase selected aspects of device performance, including beam quality, spectral stability, and output power.
Japanese Journal Of Applied Physics
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Author :
language : en
Publisher:
Release Date : 2003
Japanese Journal Of Applied Physics written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Physics categories.
Transceiver Technologies For Millimeter Wave Beam Steering Applications Band 71
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Author : Yi-Fan Tsao
language : en
Publisher: Cuvillier Verlag
Release Date : 2022-11-08
Transceiver Technologies For Millimeter Wave Beam Steering Applications Band 71 written by Yi-Fan Tsao and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-11-08 with Technology & Engineering categories.
During the past years, wireless communication systems have been rapidly advancing to meet the high data-rate requirements of various emerging applications. However, the existing transceivers have typically been demonstrated using CMOS-compatible technologies that deliver a relatively low equivalent isotropic radiated power in a small unit cell. Moreover, the particular device characteristics are limiting the linear region for operation. Therefore, the main focus of this dissertation is to present and discuss new design methods for transceivers to solve these issues. To reduce the complexity of the transceiver module for further phased-array scaling, a low-noise power amplifier design approach is designed using a 0.15-μm GaN-on-SiC high-electron mobility transistor technology (HEMT). Utilizing a traded off interstage matching topology between loss and bandwidth, the conversion loss induced by the matching network could be effectively reduced. A stacked-FET configuration was adopted to enhance the power handling of the RF switch. Further improvement on the isolation bandwidth was investigated using theoretical analysis on the intrinsic effect of the passive HEMTs. With the successful implementation of the RF front-end circuits, transceiver modules were integrated on Rogers RO3010 substrate. The planar dual exponentially tapered slot antenna phased-array system showed a compact size with simple biasing network compared to the conventional transceiver approach. The presented T/R module was characterized with an over-the-air test at a distance of 1 m, overcoming the free space path loss of 64 dB. It also shows a high flexibility for further integration with a larger number of array systems, which is very promising for future 5G communication systems.
Design Und Realisierung Gan Hemt Basierter Thz Detektoren Band 72
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Author : Adam Rämer
language : de
Publisher: Cuvillier Verlag
Release Date : 2023-03-23
Design Und Realisierung Gan Hemt Basierter Thz Detektoren Band 72 written by Adam Rämer and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-03-23 with Technology & Engineering categories.
In dieser Arbeit wird gezeigt, wie State-of-the-Art THz-Detektoren mittels eines niederfrequenten Standard MMIC Prozesses zu realisieren sind. Für den zugrundeliegenden Detektionsmechanismus wird die theoretische Grundlage hergeleitet und herausgearbeitet, wie die einzelnen Elemente des Detektors interagieren. Die THz-Detektoren sind in einem GaN-on-SiC-HEMT-MMIC-Prozess realisiert. Dabei werden Bow-Tie-Antennen, logarithmische Spiralantennen und die jeweilige komplementäre Schlitz-Antennenkonfiguration miteinander verglichen. In diesem Zusammenhang wurde ein neuartiges Design entworfen, welches in Japan, den USA und der Europäischen Union erfolgreich zum Patent angemeldet ist. Die gesamte Detektorstruktur wird durch Simulationen und Gegenüberstellungen von Messungen an gefertigten THz-Detektorstrukturen verifiziert. Im Vergleich zwischen den simulierten und den gemessenen Detektionsströmen zeigt sich, trotz noch vorhandener Unsicherheiten bei Messung und Modell, über der Frequenz von 0,1 THz bis 1,2 THz eine gute Übereinstimmung. Die Kombination einer mittels 3D-EM-Simulationen nachgebildeten passiven Antennenstruktur mit einem den inneren Transistor beschreibenden Modell zu einer Gesamtsimulation der Detektorstruktur ist ein fundamentaler Bestandteil dieser Arbeit. Die realisierten THz-Detektorstrukturen mit teils neuartigen Antennen sind bei Raumtemperatur besonders empfindlich und stellen den aktuellen Entwicklungstand von GaN-basierten THz-Detektoren dar. Der Hauptdetektionsmechanismus liegt dabei im resistiven Selbstmischen, wodurch die Detektoren ein instantanes Ansprechverhalten bei hoher Linearität besitzen.
Broad Area Laser Bars For 1 Kw Emission
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Author : Matthias M. Karow
language : en
Publisher: Cuvillier Verlag
Release Date : 2022-06-27
Broad Area Laser Bars For 1 Kw Emission written by Matthias M. Karow and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-06-27 with Technology & Engineering categories.
ndustrial laser systems for material processing applications rely on the availability of highly efficient, high-brightness diode lasers. GaAs-based broad-area laser bars play a vital role in such applications as pump sources for high-beam-quality solid-state lasers and, increasingly, as direct processing tools. This work studies 940 nm-laser bars emitting 1 kW optical power at room temperature, identifying those physical mechanisms that are currently limiting electrical-to-optical conversion efficiency as well as lateral beam quality. In the process, several diagnostic studies on bars with varied lateral-longitudinal design were carried out. The effects of technological measures for performance optimization were analyzed, yielding a new benchmark in efficiency and lateral divergence. The studies into altered resonator lengths of 4 and 6 mm as well as fill factors between 69 and 87 % successfully reduce both the voltage dropping across the device and power saturation at high currents, enabling 66 % efficiency at the operation point. Concrete measures how to reach efficiencies ≥70 % are presented thereafter, showing that doubling the efficiency value of the first 1 kW-demonstration in 2007 – amounting to 35 % – is in near reach. Investigation of the beam quality bases on a herein proposed and realized concept, in which the far field is resolved for each individual bar emitter. In this way, it is possible to determine how far-field profiles vary along the bar width and how much these variations affect the overall bar far-field. Further, such effects specific to bar structures can be separated into non-thermal and thermal influences. The effect of mechanical chip deformation (bar smile) as well as neighboring-emitter interaction has been investigated for the first time in active kW-class devices, yielding a lateral divergence as low as 8.8° at the operation point.
Nonlinear Optical Crystals A Complete Survey
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Author : David N. Nikogosyan
language : en
Publisher: Springer Science & Business Media
Release Date : 2006-03-21
Nonlinear Optical Crystals A Complete Survey written by David N. Nikogosyan and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-03-21 with Science categories.
Nonlinear optical techniques are now recognized as the most efficient means available to generate laser radiation at wavelengths that are presently inaccessible via conventional sources. This technology uses nonlinear optical crystals for the frequency conversion of laser light. The book contains the most complete and up to date reference material on properties of nonlinear optical crystals, describes their applications, both traditional and specific, and provides the main mathematical formulas necessary for the calculation of the frequency conversion process. It is a vital source of information for scientists and engineers dealing with modern applications of nonlinear optical crystals in quantum electronics, optoelectronics and laser physics.
Optics Letters
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Author :
language : en
Publisher:
Release Date : 2007
Optics Letters written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Optics categories.
Summaries Of Papers Presented At The Conference Of Lasers And Electro Optics
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Author :
language : en
Publisher:
Release Date : 2000
Summaries Of Papers Presented At The Conference Of Lasers And Electro Optics written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Electrooptics categories.