| 1. |
- Eichhorn, Marc, et al.
(author)
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Spectroscopic Foundations of Lasers : Spontaneous Emission Into a Resonator Mode
- 2015
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In: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 21:1, s. 9000216-
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Journal article (peer-reviewed)abstract
- We review the physics underlying the process of spontaneous emission, with a special focus on spontaneous emission into a resonator mode. We define the mode volume, verify the fundamental modal dimensions, present the spectral mode profile, the coherence time, the Q-factor, the Fuchtbauer-Ladenburg equation, and the Purcell factor, and discuss their influence on different types of lasers. We obtain the relation between peak emission cross section, radiative lifetime, and emission linewidth. By interpreting spontaneous emission as stimulated emission driven by vacuum fluctuations, we derive the spontaneous-emission rate into a resonator mode and establish physical expressions for the fractions of spontaneous emission and total decay from the upper laser level into this mode. Furthermore, we discuss coupling of the atomic system with the coherent field inside a lasing resonator mode, resulting in the formation of a Mollow triplet, and demonstrate that it leads to a reduction of the spontaneous-emission rate by a factor of 2.
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| 2. |
- Forsberg, Fredrik, et al.
(author)
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CMOS-integrated Si/SiGe quantum-well infrared microbolometer focal plane arrays manufactured with very large-scale heterogeneous 3-d integration
- 2015
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In: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers Inc.. - 0792-1233 .- 1077-260X .- 1558-4542. ; 21:4
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Journal article (peer-reviewed)abstract
- We demonstrate infrared focal plane arrays utilizing monocrystalline silicon/silicon-germanium (Si/SiGe) quantum-well microbolometers that are heterogeneously integrated on top of CMOS-based electronic read-out integrated circuit substrates. The microbolometers are designed to detect light in the long wavelength infrared (LWIR) range from 8 to 14 μm and are arranged in focal plane arrays consisting of 384 × 288 microbolometer pixels with a pixel pitch of 25 μm × 25 μm. Focal plane arrays with two different microbolometer designs have been implemented. The first is a conventional single-layer microbolometer design and the second is an umbrella design in which the microbolometer legs are placed underneath the microbolometer membrane to achieve an improved pixel fill-factor. The infrared focal plane arrays are vacuum packaged using a CMOS compatible wafer bonding and sealing process. The demonstrated heterogeneous 3-D integration and packaging processes are implemented at wafer-level and enable independent optimization of the CMOS-based integrated circuits and the microbolometer materials. All manufacturing is done using standard semiconductor and MEMS processes, thus offering a generic approach for integrating CMOS-electronics with complex miniaturized transducer elements
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| 3. |
- Haglund, Emanuel, 1988, et al.
(author)
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Silicon-Integrated Hybrid-Cavity 850-nm VCSELs by Adhesive Bonding: Impact of Bonding Interface Thickness on Laser Performance
- 2017
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In: IEEE Journal of Selected Topics in Quantum Electronics. - 1558-4542 .- 1077-260X. ; 23:6, s. 1700109-
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Journal article (peer-reviewed)abstract
- The impact of bonding interface thickness on the performance of 850-nm silicon-integrated hybrid-cavity vertical-cavity surface-emitting lasers (HC-VCSELs) is investigated. The HC-VCSEL is constructed by attaching a III–V “half-VCSEL” to a dielectric distributed Bragg reflector on a Si substrate using ultrathin divinylsiloxane-bis-benzocyclobutene (DVS-BCB) adhesive bonding. The thickness of the bonding interface, defined by the DVS-BCB layer together with a thin SiO2 layer on the “half-VCSEL,” can be used to tailor the performance, for e.g., maximum output power or modulation speed at a certain temperature, or temperature-stable performance. Here, we demonstrate an optical output power of 2.3 and 0.9 mW, a modulation bandwidth of 10.0 and 6.4 GHz, and error-free data transmission up to 25 and 10 Gb/s at an ambient temperature of 25 and 85 °C, respectively. The thermal impedance is found to be unaffected by the bonding interface thickness.
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| 4. |
- Heinz, D., et al.
(author)
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GaInN Quantum Wells as Optochemical Transducers for Chemical Sensors and Biosensors
- 2017
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In: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-4542 .- 1077-260X. ; 23:2, s. 15-23
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Journal article (peer-reviewed)abstract
- In this paper, investigations on gallium indium nitride (GaInN) quantum well structures as optochemical transducers in (bio) chemical sensing are presented. In contrast to the conventional electrical read-out of III-nitride-based sensors, a purely optical photoluminescence read-out is performed. A significant spectral shift of the quantum well photoluminescence is observed with varying surface modification. The spectral photoluminescence shift can be attributed to an externally induced quantum confined Stark effect caused by the adsorbed species deposited on the quantum well surface. In order to improve the sensitivity of the transducer elements, different chemical surface treatments are studied. In particular, optical sensing experiments with reducing and oxidizing gases are performed in order to investigate the quantum well photoluminescence response. Additionally, optical investigations of the iron-storage molecule ferritinwith varying iron load are presented. The iron load of this molecule is generally considered as a superior biomarker for severe illnesses, such as Alzheimer's disease. In contrast to conventional fluorescent labels, GaInN quantum wells provide a much more stable luminescence signal, and hence, are promising candidates for next generation bioanalytical sensor structures.
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| 5. |
- Jansson, Samuel, et al.
(author)
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First Polarimetric Investigation of Malaria Mosquitos as Lidar Targets
- 2019
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In: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 25:1, s. 1-8
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Journal article (peer-reviewed)abstract
- In this work, we use a novel spectral polarimetric optical tomographic imaging goniometer (SPOTIG) to investigate the scattering properties of Anopheles malaria mosquitoes to aid in their detection and identification in entomological lidar applications. Mosquitoes were mounted on a turn table, on which they were illuminated from different angles with linearly polarized near infrared light and rotated. Thus, aspect-dependent optical cross sections were retrieved in backscatter and extinction mode. The backscattering and extinction properties of male and female mosquitoes were further condensed into a pair of parameters. We investigate the wings and bodies of mosquitoes together and independently, and conclude that the wings of mosquitoes strongly scatter copolarized light and that the degree of linear polarization of light scattered by insect bodies is independent of the aspect. In lidar measurements, light scattered by insect wings can be separated from light scattered by insect bodies due to the oscillatory wing beats. Therefore, obtaining the scattering properties of bodies and wings independently is of particular interest. Finally, we conclude that 808 nm light is well suited for detecting specular reflexes produced by Anopheles wings, which has large implications for the design of entomological lidar instruments used to study malaria mosquitoes.
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| 6. |
- Lindberg, Robert, et al.
(author)
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Mapping Mode-Locking Regimes in a Polarization-Maintaining Er-Doped Fiber Laser
- 2018
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In: IEEE Journal of Selected Topics in Quantum Electronics. - : IEEE Press. - 1077-260X .- 1558-4542. ; 24:3, s. 1-9
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Journal article (peer-reviewed)abstract
- We present the performance of an all polarization-maintaining Erbium-doped fiber laser mode-locked by a multilayer graphene based saturable absorber. The cavity incorporates a Martinez-type compressor, based on a transmission grating, which allows for continuous tuning of the net cavity dispersion as well as spectral filtering. By adjusting the dispersion and the spectral bandwidth, we could operate the laser in the soliton, the dispersion managed soliton and the absorber-limited pulse regimes. The pulse durations from the laser ranged between 338 fs to 2.1 ps and the laser could be operated at nearly constant output powers in the anomalous and the normal dispersion regimes. We also conducted stability analyses based on dispersive Fourier transform measurements in the different operating regimes. Comparison of the collected spectra reveals that the soliton regime had the best overall stability.
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| 7. |
- Peacock, Anna, et al.
(author)
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Wavelength conversion and supercontinuum generation in silicon optical fibers
- 2017
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In: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 24:3
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Journal article (peer-reviewed)abstract
- This paper describes the state of the art in wavelength conversion and supercontinuum generation using glass-clad silicon core optical fibers. Such semiconductor fibers have enjoyed considerable attention due to their intrinsically high third-order nonlinearities, which are markedly higher than in conventional infrared glasses. Results to date from small core silicon fibers fabricated using both the high-pressure chemical vapor deposition technique and the molten core drawing method are presented. Also discussed are directions for continued study and development, including engineering the dispersion and nonlinear properties as well as improved interconnection.
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| 8. |
- Pollnau, Markus
(author)
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Rare-Earth-Ion-Doped Channel Waveguide Lasers on Silicon
- 2015
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In: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 21:1, s. 1602512-
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Journal article (peer-reviewed)abstract
- This paper reviews the recent developments in rare-earth-ion-doped channel waveguide lasers. Optical gain in rare-earth-ion-doped waveguides has been increased by two orders of magnitude to similar to 1000 dB/cm and waveguide lasers with extremely high slope efficiencies and output powers exceeding the Watt level have been demonstrated. Of particular interest in integrated optics is the recent integration of rare-earth-ion-doped channel waveguide lasers in amorphous materials directly deposited on a silicon substrate. Remarkable performance with respect to slope efficiency, output power, and laser linewidth has been achieved.
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| 9. |
- Sennaroglu, A., et al.
(author)
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Introduction to the Special Issue on Solid-State Lasers
- 2018
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In: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X .- 1558-4542. ; 24:5
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Journal article (peer-reviewed)
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| 10. |
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