| 1. |
- Agate, B., et al.
(författare)
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Portable ultrafast blue light sources designed with frequency doubling in KTP and KNbO3
- 2004
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X .- 1558-4542. ; 10:6, s. 1268-1276
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate an effective means of achieving compact, truly portable, and entirely self-contained ultrafast blue light sources. Using a variety of nonlinear media to achieve simple second-harmonic generation of a femtosecond Cr:LiSAF laser, we investigate the relative merits of aperiodically poled bulk and waveguide nonlinear crystals in comparison to periodically poled structures. Such a compact and convenient source of ultrashort laser pulses in the blue spectral region could be of great interest for on-site applications spanning a host of disciplines, such as biomedical imaging, optical micromanipulation, and high-resolution spectroscopy.
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| 2. |
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| 3. |
- Borgström, Magnus, et al.
(författare)
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Nanowires With Promise for Photovoltaics
- 2011
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 17:4, s. 1050-1061
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy harvesting for electricity production is regarded as a fully credible future energy source: plentiful and without serious environmental concerns. The breakthrough for solar energy technology implementation has, however, been hampered by two issues: the conversion efficiency of light into electricity and the solar panel production cost. The use of III-V nanowires (NWs) in photovoltaics allows to respond to both these demands. They offer efficient light absorption and significant cost reduction. These low-dimensional structures can be grown epitaxially in dense NW arrays directly on silicon wafers, which are abundant and cheaper than the germanium substrates used for triple-junction solar cells today. For planar structures, lattice matching poses a strong restriction on growth. III-V NWs offer to create highly efficient multijunction devices, since multiple materials can be combined to match the solar spectrum without the need of tightly controlled lattice matching. At the same time, less material is required for NW-based solar cells than for planar-based architecture. This approach has potential to reach more than 50% in efficiency. Here, we describe our work on NW tandem solar cells, aiming toward two junctions absorbing different parts of the solar spectrum, connected in series via a tunnel diode.
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| 4. |
- Brizuela, Fernando, et al.
(författare)
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Imaging at the Nanoscale With Practical Table-Top EUV Laser-Based Full-Field Microscopes
- 2012
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 18:1, s. 434-442
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Tidskriftsartikel (refereegranskat)abstract
- The demonstration of table-top high average power extreme-ultraviolet (EUV) lasers combined with the engineering of specialized optics has enabled the demonstration of full-field microscopes that have achieved tens of nanometer spatial resolution. This paper describes the geometry of the EUV microscopes tailored to specific imaging applications. The microscope illumination characteristics are assessed and an analysis on the microscope's spatial resolution is presented. Examples of the capabilities of these table-top EUV aerial microscopes for imaging nanostructures and surfaces are presented.
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| 5. |
- Broeke, Ronald G., et al.
(författare)
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Optical-CDMA in InP
- 2007
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X .- 1558-4542. ; 13:5, s. 1497-1507
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the InP platforms for photonic integration and the development on these platforms of an optical code division multiple access (O-CDMA) system for local area networks. We demonstrate three building blocks of this system: an optical pulse source, an encoder/decoder pair, and a threshold detector. The optical pulse source consists of an integrated colliding pulse-mode laser with nearly transform-limited 10 Gb/s pulses and optical injection locking to an external clock for synchronization. The encoder/decoder pair is based on arrayed waveguide gratings. Bit-error-rate measurements involving six users at 10 Gb/s showed error-free transmission, while O-CDMA codes were calibrated using frequency resolved optical gating. For threshold detection after the decoder, we compared two Mach-Zehnder interferometer (MZI)-based optical thresholding schemes and present results on a new type of electroabsorber-based MZI.
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| 6. |
- Brydegaard, Mikkel, et al.
(författare)
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High Dynamic Range in Entomological Scheimpflug Lidars
- 2021
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 27:4
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Tidskriftsartikel (refereegranskat)abstract
- Minimizing insecticide use, preventing vector diseases and facilitating biodiversity assessments are suitable applications of recent advances in photonic insect surveillance and entomological lidar. The tools also comprise a new window into fundamental aspect of the fascinating life and ecology of insects and their predators in situ. At the same time, it is evident that lidars are subject to finite detection range given by the instrument noise and saturation levels, and therefore, intervals of the biomass spectra are sectioned at different ranges. The Scheimpflug lidar allows an interesting trade-off between high sample rate and low pulse energy for retrieving wing beat harmonics and slow sample rates with high pulse energy for detecting small species far away. In this paper, we review and revise calibration, sizing and associated deficiencies, and report count rates to 104 insects/minute up to 2 km range. We investigate if and how high dynamic range can be exploited in entomological lidar and also how fast and slow sample rates could complement each other and capture a wider span of the biomass spectrum. We demonstrate that smaller insect can be detected further away by long exposures and show consistency between the captured biomass size spectra. However, we find unexpected discrepancies between short and long exposures in the range distributions. We found that vertebrates as well as specular insects can saturate signals. Error sources and limitations are elaborated on.
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| 7. |
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| 8. |
- Caroff, Philippe, et al.
(författare)
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Crystal Phases in III-V Nanowires: From Random Toward Engineered Polytypism
- 2011
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 17:4, s. 829-846
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Tidskriftsartikel (refereegranskat)abstract
- III-V nanowires (NWs) are promising for a wide range of applications, ranging from optics to electronics, energy, and biological sensing. The structural quality of NWs is of paramount importance for the performance of such future NW-based devices. Random structural defects and polytypism occur naturally in semiconductor NWs, but progress both on the theoretical understanding and experimental control have been achieved recently. Here, we review progress towards the realization of perfect wurtzite and zinc-blende phases in III-VNWs, eventually leading to true phase engineering in single NWs.
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| 9. |
- Chacinski, Marek, et al.
(författare)
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100 Gb/s ETDM Transmitter Module
- 2010
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 16:5, s. 1321-1327
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Tidskriftsartikel (refereegranskat)abstract
- Components of a 100 Gb/s transmitter with electrical time-division multiplexing are presented as following: electrical multiplexer, driver amplifier, and large-bandwidth distributed feedback-traveling-wave electro-absorption modulator module. The performance of the parts of the transmitter, as well as the complete chain, is investigated for data operation and transmission in future 100 Gb/s Ethernet (100GbE). Clearly open eye diagrams at 100 Gb/s are demonstrated together with data transmission over 300 m long standard single mode fiber link.
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| 10. |
- Chen, Biao, et al.
(författare)
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Efficient and fine scheduling algorithm for bandwidth allocation in Ethernet passive optical networks
- 2006
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 12:4, s. 653-660
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Tidskriftsartikel (refereegranskat)abstract
- A novel fine scheduling algorithm is introduced for upstream bandwidth allocation in an Ethernet-based passive optical network. This scheduling algorithm consists of an inter optical network unit (ONU) scheduler at the optical line terminal (OLT) and an intra-ONU scheduler at each ONU. In the inter-ONU scheduling, a novel GATE/REPORT approach is introduced to eliminate the unused remainders without transmission delay and maximize the utilization of bandwidth. Our novel intra-ONU scheduler gives fair bandwidth allocation to the queues of different priorities for each user in a hierarchical and decentralized way. Numerical results have shown that our overall scheduling algorithm can fulfill various requirements of delay and throughput for the transmission of multimedia traffic for each end user..
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