@article{64307,
  author       = {{Gurevich, Evgeny L. and Hofmann, Martin R. and Gerhardt, Nils Christopher and Neutsch, Krisztian}},
  journal      = {{Nanomaterials}},
  number       = {{3}},
  title        = {{{Investigation of laser-induced periodic surface structures using synthetic optical holography}}},
  doi          = {{10.3390/nano12030505}},
  volume       = {{13}},
  year         = {{2022}},
}

@inproceedings{59780,
  author       = {{Petrov, Dmitry and Taron, Kim-Florian and Hilleringmann, Ulrich and Joubert, Trudi-Heleen}},
  booktitle    = {{2021 Smart Systems Integration (SSI)}},
  publisher    = {{IEEE}},
  title        = {{{Low-cost Sensor System for on-the-field Water Quality Analysis}}},
  doi          = {{10.1109/ssi52265.2021.9466956}},
  year         = {{2021}},
}

@inproceedings{59777,
  author       = {{Hilleringmann, Ulrich and Petrov, Dmitry and Mwammenywa, Ibrahim and Kagarura, Geoffrey Mark}},
  booktitle    = {{2021 IEEE AFRICON}},
  publisher    = {{IEEE}},
  title        = {{{Local Power Control using Wireless Sensor System for Microgrids in Africa}}},
  doi          = {{10.1109/africon51333.2021.9570970}},
  year         = {{2021}},
}

@inproceedings{39397,
  author       = {{Petrov, Dmitry and Kroschewski, Konstantin and Hilleringmann, Ulrich}},
  booktitle    = {{2021 Smart Systems Integration (SSI)}},
  publisher    = {{IEEE}},
  title        = {{{Microcontroller Firmware Design for Industrial Wireless Sensors}}},
  doi          = {{10.1109/ssi52265.2021.9467010}},
  year         = {{2021}},
}

@article{59779,
  author       = {{Petrov, Dmitry and Hilleringmann, Ulrich}},
  issn         = {{2415-6698}},
  journal      = {{Advances in Science, Technology and Engineering Systems Journal}},
  number       = {{5}},
  pages        = {{267--272}},
  publisher    = {{ASTES Journal}},
  title        = {{{Low-Power Primary Cell with Water-Based Electrolyte for Powering of Wireless Sensors}}},
  doi          = {{10.25046/aj060529}},
  volume       = {{6}},
  year         = {{2021}},
}

@inproceedings{59774,
  author       = {{Petrov, Dmitry and Kroschewski, Konstantin and Mwammenywa, Ibrahim and Kagarura, Geoffrey Mark and Hilleringmann, Ulrich}},
  booktitle    = {{2021 IEEE Sensors}},
  publisher    = {{IEEE}},
  title        = {{{Low-Cost NB-IoT Microgrid Power Quality Monitoring System}}},
  doi          = {{10.1109/sensors47087.2021.9639641}},
  year         = {{2021}},
}

@article{59686,
  abstract     = {{The monolithic growth of III–V materials directly on Si substrates provides a promising integration approach for passive and active silicon photonic integrated circuits but still faces great challenges in crystal quality due to misfit defect formation. Nano-ridge engineering is a new approach that enables the integration of III–V based devices on trench-patterned Si substrates with very high crystal quality. Using selective area growth, the III–V material is deposited into narrow trenches to reduce the dislocation defect density by aspect ratio trapping. The growth is continued out of the trench pattern and a box-shaped III–V nano-ridge is engineered by adjusting the growth parameters. A flat (001) GaAs nano-ridge surface enables the epitaxial integration of a common InGaAs/GaAs multi-quantum-well (MQW) structure as an optical gain medium to build a laser diode. In this study, a clear correlation is found between the photoluminescence (PL) lifetime, extracted from time-resolved photoluminescence (TRPL) measurements, with the InGaAs/GaAs nano-ridge size and defect density, which are both predefined by the nano-ridge related pattern trench width. Through the addition of an InGaP passivation layer, a MQW PL lifetime of up to 800 ps and 1000 ps is measured when pumped at 900 nm (only QWs were excited) and 800 nm (QWs + barrier excited), respectively. The addition of a bottom carrier blocking layer further increases this lifetime to ∼2.5ns (pumped at 800 nm), which clearly demonstrates the high crystal quality of the nano-ridge material. These TRPL measurements not only deliver quick and valuable feedback about the III–V material quality but also provide an important understanding for the heterostructure design and carrier confinement of the nano-ridge laser diode.}},
  author       = {{Shi, Yuting and Kreuzer, Lisa C. and Gerhardt, Nils Christopher and Pantouvaki, Marianna and Van Campenhout, Joris and Baryshnikova, Marina and Langer, Robert and Van Thourhout, Dries and Kunert, Bernardette}},
  issn         = {{0021-8979}},
  journal      = {{Journal of Applied Physics}},
  number       = {{10}},
  publisher    = {{AIP Publishing}},
  title        = {{{Time-resolved photoluminescence characterization of InGaAs/GaAs nano-ridges monolithically grown on 300 mm Si substrates}}},
  doi          = {{10.1063/1.5139636}},
  volume       = {{127}},
  year         = {{2020}},
}

@article{59685,
  abstract     = {{Introducing spin-polarized carriers in semiconductor lasers reveals an alternative path to realize room-temperature spintronic applications, beyond the usual magnetoresistive effects. Through carrier recombination, the angular momentum of the spin-polarized carriers is transferred to photons, thus leading to the circularly polarized emitted light. The intuition for the operation of such spin-lasers can be obtained from simple bucket and harmonic oscillator models, elucidating their steady-state and dynamic response, respectively. These lasers extend the functionalities of spintronic devices and exceed the performance of conventional (spin-unpolarized) lasers, including an order of magnitude faster modulation frequency. Surprisingly, this ultrafast operation relies on a short carrier spin relaxation time and a large anisotropy of the refractive index, both viewed as detrimental in spintronics and conventional lasers. Spin-lasers provide a platform to test novel concepts in spin devices and offer progress connected to the advances in more traditional areas of spintronics.}},
  author       = {{Žutić, Igor and Xu, Gaofeng and Lindemann, Markus and Faria Junior, Paulo E. and Lee, Jeongsu and Labinac, Velimir and Stojšić, Kristian and Sipahi, Guilherme M. and Hofmann, Martin R. and Gerhardt, Nils Christopher}},
  issn         = {{0038-1098}},
  journal      = {{Solid State Communications}},
  publisher    = {{Elsevier BV}},
  title        = {{{Spin-lasers: spintronics beyond magnetoresistance}}},
  doi          = {{10.1016/j.ssc.2020.113949}},
  volume       = {{316-317}},
  year         = {{2020}},
}

@article{59684,
  abstract     = {{<jats:p>In this paper, we present a confocal laser scanning holographic microscope for the investigation of buried structures. The multimodal system combines high diffraction limited resolution and high signal-to-noise-ratio with the ability of phase acquisition. The amplitude and phase imaging capabilities of the system are shown on a test target. For the investigation of buried integrated semiconductor structures, we expand our system with an optical beam induced current modality that provides additional structure-sensitive contrast. We demonstrate the performance of the multimodal system by imaging the buried structures of a microcontroller through the silicon backside of its housing in reflection geometry.</jats:p>}},
  author       = {{Schnitzler, Lena and Neutsch, Krisztian and Schellenberg, Falk and Hofmann, Martin R. and Gerhardt, Nils Christopher}},
  issn         = {{1559-128X}},
  journal      = {{Applied Optics}},
  number       = {{4}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Confocal laser scanning holographic microscopy of buried structures}}},
  doi          = {{10.1364/ao.403687}},
  volume       = {{60}},
  year         = {{2020}},
}

@inproceedings{39405,
  author       = {{Petrov, Dmitry and Hilleringmann, Ulrich}},
  booktitle    = {{2020 IEEE SENSORS}},
  publisher    = {{IEEE}},
  title        = {{{Water-based primary cell for powering of wireless sensors}}},
  doi          = {{10.1109/sensors47125.2020.9278891}},
  year         = {{2020}},
}

@inproceedings{59781,
  author       = {{Petrov, Dmitry and Meyers, Thorsten and Reker, Julia and Hilleringmann, Ulrich}},
  booktitle    = {{Fifth Conference on Sensors, MEMS, and Electro-Optic Systems}},
  editor       = {{du Plessis, Monuko}},
  publisher    = {{SPIE}},
  title        = {{{Doctor blade system for the deposition of thin semiconducting films}}},
  doi          = {{10.1117/12.2501307}},
  year         = {{2019}},
}

@inproceedings{39943,
  author       = {{Schmidt, Marco and Petrov, Dmitry and Hedayat, Christian and Hilleringmann, Ulrich and Otto, Thomas}},
  booktitle    = {{Smart Systems Integration; 13th International Conference and Exhibition on Integration Issues of Miniaturized Systems}},
  pages        = {{1--4}},
  title        = {{{Wireless power supply for a RFID based sensor platform}}},
  year         = {{2019}},
}

@inproceedings{39944,
  author       = {{Petrov, Dmitry and Schmidt, Marco and Hilleringmann, Ulrich and Hedayat, Christian and Otto, Thomas}},
  booktitle    = {{Smart Systems Integration; 13th International Conference and Exhibition on Integration Issues of Miniaturized Systems}},
  pages        = {{1--4}},
  title        = {{{RFID based sensor platform for industry 4.0 application}}},
  year         = {{2019}},
}

@inproceedings{64361,
  author       = {{Neutsch, Krisztian and Hofmann, Martin R. and Gerhardt, Nils Christopher and Schnitzler, Lena and Tranelis, Marlon J.}},
  booktitle    = {{Practical Holography XXXIII: Displays, Materials, and Applications}},
  title        = {{{Three-dimensional particle localization with common-path digital holographic microscopy}}},
  doi          = {{10.1117/12.2509448}},
  year         = {{2019}},
}

@inbook{64360,
  author       = {{Gerhardt, Nils Christopher and Žutić, Igor and Lee, Jeongsu and Gøthgen, Christian and Farla, Paulo E., Junior and Xu, Gaofeng and Sipahi, Guilherme M.}},
  booktitle    = {{Nanoscale spintronics and applications}},
  pages        = {{499 -- 540}},
  title        = {{{Semiconductor spin-lasers}}},
  year         = {{2019}},
}

@article{59687,
  abstract     = {{Lasers have both ubiquitous applications and roles as model systems in which non-equilibrium and cooperative phenomena can be elucidated1. The introduction of novel concepts in laser operation thus has potential to lead to both new applications and fundamental insights2. Spintronics3, in which both the spin and the charge of the electron are used, has led to the development of spin-lasers, in which charge-carrier spin and photon spin are exploited. Here we show experimentally that the coupling between carrier spin and light polarization in common semiconductor lasers can enable room-temperature modulation frequencies above 200 gigahertz, exceeding by nearly an order of magnitude the best conventional semiconductor lasers. Surprisingly, this ultrafast operation of the resultant spin-laser relies on a short carrier spin relaxation time and a large anisotropy of the refractive index, both of which are commonly viewed as detrimental in spintronics3 and conventional lasers4. Our results overcome the key speed limitations of conventional directly modulated lasers and offer a prospect for the next generation of low-energy ultrafast optical communication.}},
  author       = {{Lindemann, Markus and Xu, Gaofeng and Pusch, Tobias and Michalzik, Rainer and Hofmann, Martin R. and Žutić, Igor and Gerhardt, Nils Christopher}},
  issn         = {{0028-0836}},
  journal      = {{Nature}},
  number       = {{7751}},
  pages        = {{212--215}},
  publisher    = {{Springer Science and Business Media LLC}},
  title        = {{{Ultrafast spin-lasers}}},
  doi          = {{10.1038/s41586-019-1073-y}},
  volume       = {{568}},
  year         = {{2019}},
}

@inproceedings{64371,
  author       = {{Hofmann, Martin R. and Lenz, Marcel and Krug, Robin and Gerhardt, Nils Christopher and Schmieder, Kirsten and Dillmann, Christopher and Welp, Hubert}},
  booktitle    = {{Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXII}},
  title        = {{{Brain tissue analysis using texture features based on optical coherence tomography images}}},
  doi          = {{10.1117/12.2292032}},
  year         = {{2018}},
}

@inproceedings{64372,
  author       = {{Lenz, Marcel and Krug, Robin and Gerhardt, Nils Christopher and Schmieder, Kirsten and Hofmann, Martin R. and Dillmann, Christopher and Welp, Hubert}},
  booktitle    = {{Optics, Photonics, and Digital Technologies for Imaging Applications V}},
  title        = {{{Classification of brain tissue with optical coherence tomography by employing texture analysis}}},
  doi          = {{10.1117/12.2307701}},
  year         = {{2018}},
}

@inproceedings{64376,
  author       = {{Hofmann, Martin R. and Gerhardt, Nils Christopher and Finkeldey, Markus and Göring, Lena}},
  booktitle    = {{Practical Holography XXXII: Displays, Materials, and Applications}},
  title        = {{{Digital holography for the investigation of buried structures with a common-path reflection microscope}}},
  doi          = {{10.1117/12.2289524}},
  year         = {{2018}},
}

@inproceedings{64379,
  author       = {{Lindemann, Markus and Gerhardt, Nils Christopher and Hofmann, Martin R. and Pusch, Tobias and Michalzik, Rainer and Scherübl, Sebastian}},
  booktitle    = {{Semiconductor Lasers and Laser Dynamics VIII}},
  title        = {{{Thermally-induced birefringence in VCSELs - approaching the limits}}},
  doi          = {{10.1117/12.2306215}},
  year         = {{2018}},
}