A5056037956- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Solid State Laser Technologies
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Spectroscopy and Laser Applications
- Laser-Matter Interactions and Applications
- Optical Coatings and Gratings
- GaN-based semiconductor devices and materials
- Photonic Crystal and Fiber Optics
- Laser Material Processing Techniques
- Optical Network Technologies
- Photonic Crystals and Applications
- Advanced Fiber Optic Sensors
- Advanced Optical Sensing Technologies
- Photorefractive and Nonlinear Optics
- Optical Systems and Laser Technology
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum optics and atomic interactions
- Optical Coherence Tomography Applications
- Atomic and Subatomic Physics Research
- Advanced Measurement and Metrology Techniques
- Photocathodes and Microchannel Plates
- Advanced Semiconductor Detectors and Materials
Ferdinand-Braun-Institut
2016-2025
Kirchhoff (Germany)
2007-2024
Fermi National Accelerator Laboratory
2024
Technical University of Moldova
2022
ORCID
2022
Forschungsverbund Berlin
2008-2018
Humboldt-Universität zu Berlin
1989-2005
Karlsruhe Institute of Technology
1998-2002
Albert Einstein College of Medicine
2001
High-power broad-area diode lasers are the most efficient light sources, with 90-μm stripe GaAs-based 940-980 nm single emitters delivering > 10 W optical output at a power conversion efficiency η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub> (10 W) 65%. A review of efforts to increase is presented here and we show that for well-optimized structures, residual losses dominated by <i xmlns:xlink="http://www.w3.org/1999/xlink">p</i> -side...
We show theoretically, that the detuning between resonance frequencies of differently pumped DFB sections gives rise to two different pulsation mechanisms, 1) dispersive self Q-switching a single-mode and 2) beating oscillations modes nearly equal threshold gain. Our analysis is based on dynamic coupled wave equations accomplished with carrier rate equations. demonstrate existence certain isolated values both sections, at which longitudinal eigenmodes become degenerate. In degeneration...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> High-power quantum well lasers with high brightness in the spectral range between 650 nm and 1080 will be presented. Improved layer structures a narrow vertical far-field divergence down to angles of 15 <formula formulatype="inline"><tex Notation="TeX">$^{\circ}$</tex></formula> (full-width at half-maximum) were developed. For these structures, optimized tapered processed achieve laterally nearly...
The factors that limit both the continuous wave (CW) and pulsed output power of broad-area laser diodes driven at very high currents are investigated theoretically experimentally. decrease in gain due to self-heating under CW operation spectral holeburning operation, as well heterobarrier carrier leakage longitudinal spatial holeburning, dominant mechanisms limiting maximum achievable power.
Design and technology developments targeted at increasing both power conversion efficiency optical output of GaAs-based diode lasers are under intense study worldwide, driven by the demands commercial laser systems. The operation point is known to be limited electrical losses in p-side waveguide. In this paper an 'extreme, double asymmetric' design mitigate impact waveguide studied compared with a more conventional design. An increase highest demonstrated, but it less than expected from simulations.
An effective index model for vertical-cavity surface-emitting lasers (VCSELs) is reexamined. In a systematic manner, the basic equations are derived. Instead of indices plane reference waveguides, frequencies resonators appear. Calculations threshold gain and lasing wavelength long-wavelength VCSEL show usefulness method clarify waveguiding mechanisms in VCSELs, Both dispersion influence remarkably.
The spectral and spatial behavior of monolithically integrated distributed-feedback tapered master-oscillator power amplifiers emitting around 973 nm is experimentally theoretically investigated. We demonstrate a good agreement between experiments theory analyze peculiarities the observed dynamical regimes.
A distributed Bragg reflector (DBR) tapered diode laser with a record optical output power of 12 W and conversion efficiency about 44% is presented. The device has sixth-order surface grating shows single longitudinal mode emission at 979 nm as well nearly diffraction limited beam. At 11.4 the lateral beam propagation factor M21/e2=1.1 72% in central lobe.
We compare ridge-waveguide lasers with trench widths of 5 and 20 mum. The emission wavelength is around 1064 nm the ridge width m. maximum output power exceeds 2 W. 5-mum trench-width device exhibits a much more stable lateral far-field. full-width at half-maximum vertical far-field profile only 15deg due to super-large optical cavity.
Many physical effects can potentially limit the peak achievable output power of single emitter broad area diode lasers under high current, pulse-pumped operation conditions. Although previous studies have shown reliable to pump levels (240 A, 300 ns, and 1 kHz), was found saturate. We present here results a systematic study unambiguously determine sources this saturation. A combination detailed measurements finite element device simulation were used for diagnosis. find that measured...
For maximum fibre-coupled power, high power broad area diode lasers must operate with small lateral far field angles at continuous wave (CW) powers. However, these structures are laterally multi-moded, low beam quality and wide emission angles. In order to experimentally determine the origin of quality, spectrally resolved near measurements were performed for a laser 50 µm stripe width. Within range measured (CW optical output powers 1.5 W) is shown in just six stable modes, spatially...
GaAs-based broad-area diode lasers are needed with improved lateral beam parameter product (BPPlat) at high power. An experimental study of the factors limiting BPPlat is therefore presented, using extreme double-asymmetric (EDAS) vertical structures emitting 910 nm. Continuous wave, pulsed and polarization-resolved measurements presented compared to thermal simulation. The importance packaging-induced effects determined by comparing junction -up -down devices. Process clarified diodes...
We compare the results of different optical vertical-cavity surface-emitting laser models on position-dependent effects thin oxide apertures. Both scalar and vectorial as well hybrid are considered. Physical quantities that compared resonance wavelength, threshold material gain, modal stability. For large device diameters low-order modes, agreement between is quite good. Larger differences occur when considering smaller devices higher order modes. It also observed spread in wavelengths than for gain.
We present a detailed design and experimental study of diode laser structures emitting at 808 nm based on the combination GaAsP quantum well with well-established AlGaAs waveguide structures. By increasing thickness confinement layers structure, its vertical far field divergence is reduced down to 15° only small increase threshold current loss efficiency. 200 µm aperture 'broad area' devices achieve heat sink temperature 25 °C continuous wave (CW) output power more than 15 W wall-plug...
We report on the realization of narrow linewidth high power DFB diode lasers emitting near 1064 nm in stable longitudinal and lateral single mode. The is analyzed dependence output for with cavity lengths 1 2 mm by means a heterodyne beat note technique. minimum intrinsic 22 kHz FWHM (full width at half maximum, 100 μ s time scale) an 150 mW length mm. total mainly determined technical noise corresponds to 234 70 mW. influence current investigated compared different lengths. Re-broadening...
High-brightness laser diode technology is progressing rapidly in response to competitive and evolving markets. The large volume resonators required for high-power, high-brightness operation makes their beam parameters brightness sensitive thermal- carrier-induced lensing also multimode operation. Power quality are no longer the only concerns design of lasers. increased demand these technologies accompanied by new performance requirements, including a wider range wavelengths, direct...
When active regions that use low refractive index quantum barriers (LIQB) are combined with super large optical cavity (SLOC) designs in GaAs-based diode lasers, high-power operation extremely narrow vertical far-fields is observed. However, LIQB found to have lower slope efficiency and increased voltage. Comparison of experiment finite element device simulation shows this due hole accumulation at the edge region. Example devices using an 8.6-μm thick SLOC deliver 30 W 1065 nm divergence...
We present experimental results about edge-emitting distributed-Bragg-reflector-tapered diode lasers emitting at 980 nm. The investigated show an output power of up to 12 W with a conversion efficiency 45%. also exhibit small vertical divergence <15deg full-width half maximum (FWHM), nearly diffraction-limited beam quality, and narrow spectral linewidth FWHM smaller than pm. These properties allow efficient single-pass second harmonic generation levels more 1 488
Abstract Diode lasers are by far the most efficient currently available. With ever‐continuing improvement in diode laser technology, this type of has become increasingly attractive for a wide range biomedical applications. Compared to characteristics competing systems, simultaneously offer tunability, high‐power emission and compact size at fairly low cost. Therefore, preferred important applications, such as photocoagulation, optical coherence tomography, diffuse imaging, fluorescence...
We report further progress in the design and fabrication of high-order Bragg gratings defined by I-line projection lithography that are implemented a high-power diode laser. Simulations surface with large duty cycles predict reflectivities even for 25th order. such lasers compared spectral electro-optical properties having seventh-order gratings. Details encapsulation will also be presented.
For automotive light detection and ranging (LiDAR) systems diode lasers emitting short optical pulses with a good beam quality low wavelength shift over wide operating temperature range is needed. In this paper, theoretical experimental results of broad area laser diodes specially designed for application are presented. Optical pulse powers tens watts lengths in the 10 ns‐range wavelengths near 905 nm environmental temperatures between 15 85 °C achieved. Due to integrated Bragg grating as 65...
Abstract We present a theoretical model and numerical simulation results of the dynamics monolithic edge-emitting mode-locked tapered quantum well laser.&#xD;The comprehensive employs (2+1) dimensional traveling wave incorporates models for lateral current spreading carrier diffusion, while also addressing thermal effects in laser cavity.&#xD;Our investigation pulse generation by passive mode locking demonstrates good agreement with experimental observations. Furthermore, we perform...
We perform modeling and dynamic simulations of all-semiconductor photonic crystal surface-emitting lasers (PCSELs). A two-dimensional consists a GaAs layer with InGaP features, repeating periodically in both lateral directions. In our simulations, we demonstrate that crystals large isosceles triangular having base angle close to 71.5°, enable suppression higher-order modes achieve single-mode lasing large-area PCSELs under moderate high pump levels.