Share

A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation

2022-05-13 Technology & Engineering
Download A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation PDF Online Free

Author :
Release : 2022-05-13
Genre : Technology & Engineering
Kind : eBook
Book Rating : 13X/5 ( reviews)

GET EBOOK


Book Synopsis A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation by : Norman Ruhnke

Download or read book A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation written by Norman Ruhnke. This book was released on 2022-05-13. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Transceiver Technologies for Millimeter-Wave Beam Steering Applications (Band 71)

2022-11-08 Technology & Engineering
Download Transceiver Technologies for Millimeter-Wave Beam Steering Applications (Band 71) PDF Online Free

Author :
Release : 2022-11-08
Genre : Technology & Engineering
Kind : eBook
Book Rating : 020/5 ( reviews)

GET EBOOK


Book Synopsis Transceiver Technologies for Millimeter-Wave Beam Steering Applications (Band 71) by : Yi-Fan Tsao

Download or read book Transceiver Technologies for Millimeter-Wave Beam Steering Applications (Band 71) written by Yi-Fan Tsao. This book was released on 2022-11-08. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Broad-Area Laser Bars for 1 kW-Emission

2022-06-27 Technology & Engineering
Download Broad-Area Laser Bars for 1 kW-Emission PDF Online Free

Author :
Release : 2022-06-27
Genre : Technology & Engineering
Kind : eBook
Book Rating : 261/5 ( reviews)

GET EBOOK


Book Synopsis Broad-Area Laser Bars for 1 kW-Emission by : Matthias M. Karow

Download or read book Broad-Area Laser Bars for 1 kW-Emission written by Matthias M. Karow . This book was released on 2022-06-27. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73)

2023-09-19
Download Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) PDF Online Free

Author :
Release : 2023-09-19
Genre :
Kind : eBook
Book Rating : 825/5 ( reviews)

GET EBOOK


Book Synopsis Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) by : Jan-Philipp Koester

Download or read book Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) written by Jan-Philipp Koester. This book was released on 2023-09-19. Available in PDF, EPUB and Kindle. Book excerpt: 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

2003 Physics
Download Japanese Journal of Applied Physics PDF Online Free

Author :
Release : 2003
Genre : Physics
Kind : eBook
Book Rating : /5 ( reviews)

GET EBOOK


Book Synopsis Japanese Journal of Applied Physics by :

Download or read book Japanese Journal of Applied Physics written by . This book was released on 2003. Available in PDF, EPUB and Kindle. Book excerpt:

You may also like...