Dr. Nils C. Gerhardt

Akademischer Rat - Chair Photonik und Terahertztechnologie

Address

Lehrstuhl für Photonik und Terahertztechnologie

room: ID 04/323
phone:: (+49)(0)234 / 32 - 26514
Fax:: (+49)(0)234 / 32 - 14167
Email:: nils.gerhardt@rub.de

projects

Courses

Publications

Spin relaxation length in quantum dot spin LEDs

Henning Höpfner, Carola Fritsche, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, Martin R. Hofmann - phys. stat. sol., in press (2013)

Quantitative phase analysis through scattering media by depth-filtered digital holography

Sebastian Goebel, Volker Jaedicke, Nektarios Koukourakis, Helge Wiethoff, Adamou Adinda-Ougba, Nils C. Gerhardt, Hubert Welp , Martin R. Hofmann - Proc. SPIE 8589, Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XX, 85891J (February 22, 2013); doi:10.1117/12.2001159

Spectroscopic optical coherence tomography with graphics processing unit based analysis of three dimensional data sets

Volker Jaedicke, Semih Agcaer , Sebastian Goebel, Nils C. Gerhardt, Hubert Welp, Martin R. Hofmann - Proc. SPIE 8592, Biomedical Applications of Light Scattering VII, 859215 (February 21, 2013); doi:10.1117/12.2000464

Non-exponential photoluminescence transients in Ga(NAsP) lattice matched to (001) silicon substrate

K. Jandieri, B. Kunert, S. Liebich, M. Zimprich, K. Volz, W. Stolz, F. Gebhard, S.D. Baranovskii, Nektarios Koukourakis, Nils C. Gerhardt, Martin R. Hofmann - Phys. Rev. B, Vol.87, No.3, 035303 (2013)

Photoacoustic Blood Oxygenation Imaging Based on Semiconductor Lasers

Claus-Stefan Friedrich, Martin P. Mienkina, Carsten Brenner, Nils C. Gerhardt, Manfred Jörger, Andreas Strauß, Martin Beckmann, Georg Schmitz, Martin R. Hofmann - Photonics and Optoelectronics (P&O) 1, 48 (2012)

Quantum Dot Spintronics: Fundamentals and Applications

A. Ludwig, B. Sothmann, Henning Höpfner, Nils C. Gerhardt, J. Nannen, T. Kümmell, J. König, Martin R. Hofmann , G. Bacher, A.D. Wieck - in H. Zabel and M. Farle (eds.), Magnetic Nanostructures, Springer Tracts in Modern Physics 246, 235 (2012)

"Erratum: "Room temperature spin relaxation length in spin light-emitting diodes"

Henning Höpfner, Mingyuan Li, Nils C. Gerhardt, Martin R. Hofmann , A. Ludwig, A. Ebbing, D. Reuter, A.D. Wieck, F. Stromberg, W. Keune, H. Wende - [Appl. Phys. Lett. 99, 051102 (2011)]”, Appl. Phys. Lett. 100 (26), 269902 (2012)

Analysis of birefringence controlled ultrafast polarization oscillations in spin vertical-cavity surface-emitting lasers

Mingyuan Li, T. Ackemann, Nils C. Gerhardt, Martin R. Hofmann - EOS Annual Meeting, Aberdeen, UK (2012)

Spin-Controlled Vertical-Cavity Surface-Emitting Lasers

Nils C. Gerhardt, Martin R. Hofmann - Advances of Optical Technologies, 2012, 268949 (2012)

Time-resolved photoluminescence and optical gain in Ga(NAsP) heterostructures pseudomorphically grown on silicon

Nils C. Gerhardt, Nektarios Koukourakis, Max Klimasch, Martin R. Hofmann , S. Liebich, M. Zimprich, K. Volz, W. Stolz, B. Kunert - E-MRS Spring Meeting, Strasbourg, France (2012)

Magnetic field dependence of the spin relaxation length in spin light-emitting diodes

Henning Höpfner, Carola Fritsche, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, Martin R. Hofmann - Applied Physics Letters 101 (11), 112402 (2012)

Spin relaxation length in quantum dot spin LEDs

Henning Höpfner, Carola Fritsche, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, Martin R. Hofmann - NOEKS11, Stuttgart, September 2012

Depth-filtered digital holography

Nektarios Koukourakis, Volker Jaedicke, Adamou Adinda-Ougba, Sebastian Goebel, Helge Wiethoff, Henning Höpfner, Nils C. Gerhardt, Martin R. Hofmann - Optics Express Vol. *20*, Iss. 20, 22636--22648 (2012)

Signal Processing for Spectroscopic Optical Coherence Tomography

Sebastian Goebel, Semih Agcaer , Volker Jaedicke, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - Biomedizinische Technik. Biomedical engineering, vol. 57, p. 4258, Aug. 2012

System development for Spectroscopic Optical Coherence Tomography

Volker Jaedicke, Semih Agcaer , Sebastian Goebel, Helge Wiethoff, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - Biomedizinische Technik. Biomedical engineering, vol. 57, p. 4245, Aug. 2012

Ultrafast spin-induced polarization oscillations in vertical-cavity surface-emitting lasers

Nils C. Gerhardt, Mingyuan Li, Hendrik Jähme, Henning Höpfner, Thorsten Ackemann, Martin R. Hofmann - VCSEL Day 2012, Berlin, June 2012

High room-temperature optical gain in Ga(NAsP)/Si heterostructures

Nektarios Koukourakis, Christina Bückers, Dominic A. Funke, Nils C. Gerhardt, Sven Liebich, Sangam Chatterjee, Christoph Lange, Martin Zimprich, Kertsin Volz, Wolfgang Stolz, B. Kunert, S.W. Koch, Martin R. Hofmann - Applied Phys. Letters *100, *092107 (2012)

Photoluminescence and optical gain of Ga(NAsP) heterostructures pseudomorphically grown on silicon (001) substrate

Nektarios Koukourakis, Max Klimasch, Dominic A. Funke, Nils C. Gerhardt, Martin R. Hofmann , Sven Liebich, Martin Zimprich, Bernardette Kunert, Kerstin Volz, Wolfgang Stolz - SPIE Photonics West (OPTO), San Francisco (2012), [82660R]

Photoluminescence and optical gain of Ga(NAsP) heterostructures pseudomorphically grown on silicon (001) substrate

Room temperature spin relaxation in quantum dot based spin-optoelectronic devices

Henning Höpfner, Mingyuan Li, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, Martin R. Hofmann - SPIE Photonics West 2012, Ultrafast Phenomena and Nanophotonics XVI, 8260-09, San Francisco, USA

Room temperature spin relaxation in quantum dot based spin-optoelectronic devices

Henning Höpfner, Mingyuan Li, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, Martin R. Hofmann - Proceedings of SPIE, 8260, 82600A (2012) DOI: 10.1117/12.907821

Multispectral photoacoustic coded excitation using pseudorandom codes

Martin Beckmann, Claus-Stefan Friedrich, Martin P. Mienkina, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc SPIE 8223, 2012, pp 82231E-1 - 82231E-8 doi:10.1117/12.907427

Ultrafast spin-induced polarization oscillations with tunable lifetime in vertical-cavity surface-emitting lasers

Nils C. Gerhardt, Mingyuan Li, Hendrik Jähme, Henning Höpfner, T. Ackemann, Martin R. Hofmann - Appl. Phys. Lett. 99, 151107 (2011)

Photorefractive two-wave mixing for image amplification in digital holography

Nektarios Koukourakis, Tarek Abdelwahab, Mingyuan Li, Henning Höpfner, Ryan Yiu Wai Lai, Emmanouil Darakis, Carsten Brenner, Nils C. Gerhardt, Martin R. Hofmann - OPTICS EXPRESS Vol. 19, No. 22 22004 (2011)

Photoacoustic Coded Excitation using Periodically Perfect Sequences

Martin Beckmann, Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - IEEE Int. Ultrasonics Symposium 2011, Orlando, FL, 2011, pp. 1179 - 1182 doi:10.1109/ULTSYM.2011.0290

Room temperature spin relaxation length in spin light-emitting diodes

Henning Höpfner, Mingyuan Li, Nils C. Gerhardt, Martin R. Hofmann , Arne Ludwig, Astrid Ebbing, Dirk Reuter, Andreas D. Wieck, Frank Stromberg, Heiko Wende, Werner Keune - Appl. Phys. Lett. 99 (5) 051102 (2011)

Birefringence and spin controlled ultrafast polarization oscillations in vertical-cavity surface-emitting lasers

Mingyuan Li, Hendrik Jähme, Henning Höpfner, Nils C. Gerhardt, Martin R. Hofmann , T. Ackemann - CLEO Europe 2011, Munich, Germany

Quantitative photoacoustic blood oxygenation measurement of whole porcine blood samples using a multi-wavelength semiconductor laser system

Claus-Stefan Friedrich, Martin P. Mienkina, Carsten Brenner, Nils C. Gerhardt, Manfred Jörger, Andreas Strauß, Martin Beckmann, Georg Schmitz, Martin R. Hofmann - SPIE / OSA European Conferences on Biomedical Optics 2011, 8088-40, Munich, Germany, 2011

Electrical spin injection inInAs quantum dots at room temperature and adjustment of the emission wavelength for spintronic applications

A. Ludwig, R. Roescu, A.K. Rai, K. Trunov, F. Stromberg, Mingyuan Li, Henning Höpfner, A. Ebbing, Nils C. Gerhardt, Martin R. Hofmann , H. Wende, W. Keune, D. Reuter, A.D. Wieck - Journal of Crystal Growth, Volume 323, Issue 1, 15 May 2011, Pages 376-379

Spectroscopic optical coherence tomography for substance identification

Volker Jaedicke, Helge Wiethoff, Semih Agcaer , Christoph Kasseck, Nils C. Gerhardt, Hubert Welp, Martin R. Hofmann - Proc. SPIE 8091, 80911U (2011), DOI:10.1117/12.889651

Spectroscopic optical coherence tomography for substance identification

Volker Jaedicke, Helge Wiethoff, Semih Agcaer , Christoph Kasseck, Nils C. Gerhardt, Hubert Welp, Martin R. Hofmann - ECBO 2011, Munich, Germany

Spin induced gigahertz polarization oscillations in vertical-cavity surface-emitting laser devices

Mingyuan Li, Hendrik Jähme, Henning Höpfner, Nils C. Gerhardt, Martin R. Hofmann , T. Ackemann - SPIE Photonics West 2011, San Francisco, USA

High modal gain in Ga(NAsP)/(BGa)((As)P) heterostructures grown lattice-matched on (001) silicon

Nektarios Koukourakis, Dominic A. Funke, Nils C. Gerhardt, Martin R. Hofmann , S. Liebich, S. Zinnkann, M. Zimprich, A. Beyer, S. Chatterjee, C. Bückers, S. W. Koch, K. Volz, W. Stolz, B. Kunert - SPIE Photonics West (OPTO), San Francisco (2011), [7939-79]

Substance Identification in Spectroscopic Optical Coherence Tomograhpy Using Pattern Recognition

Volker Jaedicke, Christoph Kasseck, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - in Frontiers in Optics, OSA Technical Digest (CD) (Optical Society of America, 2010), paper FTuY2

Spectral pattern classification in optical coherence tomography

H. Welp, Volker Jaedicke, Christoph Kasseck, Nils C. Gerhardt, Martin R. Hofmann - 55th IWK 2010, Ilmenau, Germany

Birefringence controlled room-temperature picosecond spin dynamics close to the threshold of vertical-cavity surface-emitting laser devices

Mingyuan Li, Hendrik Jähme, Henning Höpfner, Nils C. Gerhardt, Martin R. Hofmann , T. Ackemann - Appl. Phys. Lett. 97, 191114

Gigahertz Circular Polarization Oscillations in Spin-Polarized Vertical-Cavity Surface-Emitting Lasers

Nils C. Gerhardt, Mingyuan Li, Hendrik Jähme, Martin R. Hofmann , T. Ackemann - NOEKS 2010, Paderborn, Germany

Laser gain in dilute nitride semiconductor quantum well systems – a microscopic analysis

C. Bückers, S.W. Koch, J. Hader, J.V. Moloney, B. Kunert, S. Liebich, K. Volz, W. Stolz, Nektarios Koukourakis, Nils C. Gerhardt, Martin R. Hofmann - ICOOPMA, Budapest, Hungary

Monospectral Photoacoustic Imaging using Legendre Sequences

Martin Beckmann, Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc IEEE International Ultrasonics Symposium, 2010, pp. 386 - 389 doi:10.1109/ULTSYM.2010.5935648

Optical gain in Ga(NAsP)/(BGa)((As)P) heterostructures pseudomorphically grown on Si(001) substrate

Nils C. Gerhardt, Nektarios Koukourakis, Dominic A. Funke, Martin R. Hofmann , S. Liebich, S. Zinnkann, M. Zimprich, S. Chatterjee, K. Volz, W. Stolz - E-MRS Spring Meeting, Strasbourg, France

Properties of Spin.Optoelectronic-Devices

Nils C. Gerhardt, Mingyuan Li, Henning Höpfner, Stephan Hövel, Carsten Brenner, Martin R. Hofmann , A. Ludwig, F.-Y. Lo, D. Reuter, A. Wieck, A. Ebbing, K. Westerholt, H. Zabel, E. Schuster, F. Stromberg, H. Wende, W. Keune, T. Ackemann - Tutorial, Workshop on New Materials – New Functionalities, Marburg, Germany – Invited

Substance identification by depth resolved spectroscopic pattern reconstruction in frequency domain optical coherence tomography

Christoph Kasseck, Volker Jaedicke, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - Optics Communications (2010) (Volume 283, Issue 23, 1 December 2010, Pages 4816-4822)

Monospectral Photoacoustic Imaging using Legendre Sequences

Martin Beckmann, Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann - 2010 IEEE Ultrasonics Symposium (IUS) , San Diego, CA, USA, 2010

Photorefractive Two-Wave Mixing for Image Amplification in Digital Holography

Nektarios Koukourakis, Nils C. Gerhardt, Martin R. Hofmann , Ryan Yiu Wai Lai - OSA Conference paper FThBB5

Spectroscopic image analysis with pattern recognition in frequency domain optical coherence tomography

Volker Jaedicke, Christoph Kasseck, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - OSA Biomedical Optics Conference 2010, Miami, Florida, USA

Substance identification in spectroscopic optical coherence tomograhpy using pattern recognition

Volker Jaedicke, Christoph Kasseck, Nils C. Gerhardt, Hubert Welp, Martin R. Hofmann - Frontiers in Optics, Rochester, NY, USA

Modal Gain analysis of GaNAsP Heterostructures on Silicon

Nektarios Koukourakis, Dominic A. Funke, Nils C. Gerhardt, Martin R. Hofmann , Bernardette Kunert, Sven Liebich, S. Zinnkann, M. Zimprich, A. Beyer, S. Chatterjee, C. Bückers, S. W. Koch, K. Volz, W. Stolz - OSA conference paper JWA56 (2010)

Integrity of micro-hotplates during high-temperature operation monitored by digital holographic microscopy

Ryan Yiu Wai Lai, Nektarios Koukourakis, Nils C. Gerhardt, Martin R. Hofmann , R. Meyer, S. Hamann, M. Ehmann, K. Hackl, E. Darakis, A. Ludwig - IEEE/ASME Journal of Microelectromechanical Systems 4, 1-5, Vol. 19, No. 5, p. 1175

Epitaxial Growth and Interfacial Magnetism of Spin Aligner for Remanent Spin Injection: [Fe/Tb]n/Fe/MgO/GaAs-LED as a Prototype System

E. Schuster, R. A. Brand, F. Stromberg, F.-Y. Lo, D. Reuter, A. D. Wieck, Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , H. Wende, W. Keune - J. Appl. Phys, 108, 063902

Comparison of optical coherence tomography, micro computed tomography and histology at a three-dimensionally imaged trabecular bone sample

Christoph Kasseck, Marita Kratz, Antonia Torcasio, Nils C. Gerhardt, G. Harry van Lenthe, Thilo Gambichler, Klaus Hoffmann, David B. Jones, Martin R. Hofmann - Journal of Biomedical Optics, 15(4), 046019

Spectroscopic Image Analysis with Pattern Recognition in Frequency Domain Optical Coherence Tomography

Volker Jaedicke, Christoph Kasseck, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - in Biomedical Optics, OSA Technical Digest (CD) (Optical Society of America, 2010), paper BSuD8

Depth resolved substance identification using pattern recognition in spectroscopic frequency domain optical coherence tomography

Volker Jaedicke, Christoph Kasseck, Nils C. Gerhardt, Martin R. Hofmann - Jahrestagung der DGBMT und 3-Länder-Tagung D-A-CH Rostock, Germany

Modal Gain analysis of GaNAsP Heterostructures on Silicon

Photorefractive Two-Wave Mixing for Image Amplification in Digital Holography

Nektarios Koukourakis, Nils C. Gerhardt, Martin R. Hofmann , Ryan Yiu Wai Lai - OSA Frontiers in Optics, Rochester

Frequency domain optical coherence tomography with subsequent depth resolved spectroscopic image analysis

Christoph Kasseck, Volker Jaedicke, Nils C. Gerhardt, Hubert Welp, Martin R. Hofmann - SPIE Photonics West (BIOS), San Francisco, CA, USA

Frequency domain optical coherence tomography with subsequent depth resolved spectroscopic image analysis

Christoph Kasseck, Volker Jaedicke, Nils C. Gerhardt, H. Welp, Martin R. Hofmann - Proc. SPIE 7554, 75542T (2010), DOI:10.1117/12.840029

Lasing and gain characteristics in Ga(NAsP) heterostructures on Si

C. Lange, S. Chatterjee, W.W. Rühle, Nektarios Koukourakis, Nils C. Gerhardt, Martin R. Hofmann , S. Liebich, M. Zimprich, R. Fritz, B. Kunert, K. Volz, W. Stolz - SPIE Photonics West, San Francisco, California, USA

Ultrafast circular polarization oscillations in spin-polarized vertical-cavity surface-emitting laser devices, SPIE Photonics West

Nils C. Gerhardt, Mingyuan Li, Hendrik Jähme, Henning Höpfner, Martin R. Hofmann , T. Ackemann - San Francisco, California, USA

Novel Semiconductor Based Laser Systems and Devices

Nils C. Gerhardt, Nektarios Koukourakis, Dominic A. Funke, Mingyuan Li, Henning Höpfner, Hendrik Jähme, Tobias Schlauch, Jan C. Balzer, Claus-Stefan Friedrich, Martin R. Hofmann - GAFOE Symposium, Oak Ridge, Tennessee, USA

Ultrafast circular polarization oscillations in spin-polarized vertical-cavity surface-emitting laser devices

Nils C. Gerhardt, Mingyuan Li, Hendrik Jähme, Henning Höpfner, Martin R. Hofmann , T. Ackemann - Proc. SPIE 7597, 75970Q

Electro-optical modulator arrays for the ultra-fast spectral tuning of external-cavity diode lasers

Hendrik Jähme, Nils C. Gerhardt, Martin R. Hofmann , Mike Bülters, Dieter Jäger - SIOE, Cardiff, UK

Experimental Evaluation of Photoacoustic Coded Excitation using Unipolar Golay Codes

Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Wilko Wilkening, Martin R. Hofmann , Georg Schmitz - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol 57 (7) 2010, pp 1583-1593

Multispectral photoacoustic coded excitation imaging using unipolar orthogonal Golay codes

Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin Beckmann, Martin Schiffner, Martin R. Hofmann , Georg Schmitz - Optics Express, 2010, 18, 9076-9087

Compact semiconductor laser sources for photoacoustic imaging

Claus-Stefan Friedrich, Mona-Carina Wawreczko, Martin P. Mienkina, Nils C. Gerhardt, Georg Schmitz, Martin R. Hofmann - Proc. SPIE 7177, 71772H

Depth resolved holographic imaging with variable depth resolution

Nektarios Koukourakis, Michael Breede, Nils C. Gerhardt, Martin R. Hofmann , S. Köber, M. Salvador, K. Meerholz - Electronics Letters, January 2009, Volume 45, Issue 1, p. 46-48

Compact semiconductor laser sources for photoacoustic imaging

Claus-Stefan Friedrich, Mona-Carina Wawreczko, Martin P. Mienkina, Nils C. Gerhardt, Georg Schmitz, Martin R. Hofmann - SPIE Photonics West, San Jose, California, USA

Spin-controlled optoelectronic devices

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. D. Wieck, E. Schuster, H. Wende, W. Keune - phys. stat. sol C2, 436

Optical Coherence Tomography versus Micro Computer Tomography

Christoph Kasseck, Marita Kratz, Antonia Torcasio, Nils C. Gerhardt, G. Harry van Lenthe, Thilo Gambichler, Klaus Hoffmann, David B. Jones, Martin R. Hofmann - SPIE Europe, European Conference on Biomedical Optics, Munich, Germany (accepted)

New Concepts for Depth Resolved Holographic Imaging Based on Spectrally Tunable Diode Lasers

Nektarios Koukourakis, Christoph Kasseck, Nils C. Gerhardt, Martin R. Hofmann , Daniel Rytz, Sebastian Koeber, Michael Salvador, Klaus Meerholz - OSA, CLEO/IQEC, Baltimore, Maryland, USA

New Concepts for Depth Resolved Holographic Imaging

Nektarios Koukourakis, Christoph Kasseck, Nils C. Gerhardt, Martin R. Hofmann , Daniel Rytz, Sebastian Koeber, Michael Salvador, Klaus Meerholz - OSA Spring Optics & Photonics Congress, Vancouver, BC, Canada (accepted)

Gain characteristics and lasing of Ga(NAsP) multi-quantum well structures

C. Lange, S. Chatterjee, B. Kunert, K. Volz, W. Stolz, W.W. Rühle, Nils C. Gerhardt, Martin R. Hofmann - phys. stat. sol. C6, 576

Lasing in Optically pumped Ga(NAsP)/(BGa)(AsP) Heterostructures on Silicon

C. Lange, N.S. Köster, D.J. Franzbach, S. Chatterjee, W.W. Rühle, S. Zinnkann, S. Liebich, I. Nemeth, R. Fritz, K. Volz, W. Stolz, B. Kunert, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - OSA, CLEO/IQEC, Baltimore, Maryland, USA

Lasing of lattice-matched Ga(NAsP) quantum well heterostructures monolithically integrated on (001) Si substrate

B. Kunert, I. Németh, S. Zinnkann, G. Lukin, R. Fritz, K. Volz, W. Stolz, C. Lange, N.S. Koester, D.J. Franzbach, S. Chatterjee, W. Rühle, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - SPIE Photonics West, San Jose, California, USA

Three-dimensional Bone Imaging: Optical Coherence Tomography versus Micro Computer Tomography

Christoph Kasseck, Marita Kratz, Antonia Torcasio, Nils C. Gerhardt, G. Harry van Lenthe, Thilo Gambichler, Klaus Hoffmann, David B. Jones, Martin R. Hofmann - SPIE Proceedings 7372-31

Laser operation of III/V compound material Ga(NAsP) grown lattice-matched on (001) Si substrate

B. Kunert, S. Liebich, S. Zinnkann, I. Németh, R. Fritz, K. Volz, W. Stolz, C. Lange, N.S. Koester, D.J. Franzbach, S. Chatterjee, W. Rühle, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - Device Research Conference, The Pennsylvania State University, University Park, USA

New Concepts for Depth Resolved Holographic Imaging Based on Spectrally Tunable Diode Lasers

Nektarios Koukourakis, Christoph Kasseck, Nils C. Gerhardt, Martin R. Hofmann , Daniel Rytz, Sebastian Koeber, Michael Salvador, Klaus Meerholz - OSA Conference paper CTuAA2

Lasing of the III/V compound semiconductor Ga(NAsP) integrated lattice-matched to Si substrate

B. Kunert, S. Liebich, M. Zimprich, R. Fritz, K. Volz, W. Stolz, C. Lange, N.S. Koester, S. Chatterjee, W. Rühle, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - 6th International Conference on Group IV Photonics (GFP), San Francisco, USA

Ultrafast Spin Dynamics in Spin-Polarized Vertical-Cavity Surface-Emitting Laser Devices

Nils C. Gerhardt, Stephan Hövel, Mingyuan Li, Hendrik Jähme, Martin R. Hofmann , T. Ackemann, A. Kroner, R. Michalzik

Spin dynamics in vertical-cavity surface-emitting lasers at room temperature

Mingyuan Li, Hendrik Jähme, Stephan Hövel, Andreas Bischoff, Nils C. Gerhardt, Martin R. Hofmann - SIOE, Cardiff, UK

New Concepts for Depth Resolved Holographic Imaging

Nektarios Koukourakis, Christoph Kasseck, Nils C. Gerhardt, Martin R. Hofmann , Daniel Rytz, Sebastian Köber, Michael Salvador, Klaus Meerholz - OSA Conference paper DMB6

Spin-relaxation measurements in VCSEL-structures at room temperature

Hendrik Jähme, Mingyuan Li, Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann - DPG Spring Meeting of the Condensed Matter Section, Dresden

Feasibility Study of Multispectral Photoacoustic Coded Excitation using Orthogonal Unipolar Golay Codes

Martin P. Mienkina, Eder A., Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Ultrasonics Symposium (IUS), 2009 IEEE International , pp.108-111, 20-23 Sept. 2009

Multispectral Photoacoustic Coded Excitation using Orthogonal Unipolar Golay Codes

Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc IFMBE, vol 25/II, 2009, pp 217-220

Experimental evaluation of multispectral photoacoustic coded excitation using orthogonal unipolar golay codes

Martin P. Mienkina, Eder A., Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - 442. Heraeus-Seminar "Molecular Imaging", Bad Honnef, Germany

Evaluation of Ferucarbotran (Resovist ®) as a Photoacoustic Contrast Agent

Martin P. Mienkina, Claus-Stefan Friedrich, Karin Hensel, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Biomedical Engineering, vol 54, 2009, pp 83-88

Comparison of Coding Techniques for Photoacoustic Coded Excitation

Martin P. Mienkina, Eder A., Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - International Conference on Acoustics (NAG/DAGA), 2009, pp 313-316

Single-shot holography for depth resolved three dimensional imaging

Nektarios Koukourakis, Christoph Kasseck, D. Rytz, Nils C. Gerhardt, Martin R. Hofmann - Optics Express, Vol. 17 Issue 23, pp.21015-21029

Evaluation of Ferucarbotran (Resovist®) as a photoacoustic contrast agent

Martin P. Mienkina, Claus-Stefan Friedrich, Karin Hensel, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Biomedical Engineering, vol 54, 2009, pp 83-88

Feasibility study of multispectral photoacoustic coded excitation using orthogonal unipolar Golay codes

Martin P. Mienkina, Annika Eder, Georg Schmitz, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann - Proc IEEE International Ultrasonics Symposium, 2009, pp 108-111

Comparison of Coding Techniques for Photoacoustic Coded Excitation

Martin P. Mienkina, Annika Eder, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc International Conference on Acoustics (NAG/DAGA), 2009, pp 313-316

Multispectral Photoacoustic Coded Excitation using Orthogonal Unipolar Golay Codes

Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc IFMBE, vol 25/II, 2009, pp 217-220

Room-Temperature Spin-Controlled Optoelectronic Devices

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. D. Wieck, E. Schuster, W. Keune - CLEO, San Jose, USA

Room-Temperature Spin-Optoelectronic Devices. Spin Phenomena in Reduced Dimensions

Mingyuan Li, Hendrik Jähme, Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , A. Ludwig, D. Reuter, A.D. Wieck, F. Stromberg, H. Wende, W. Keune - Regensburg, Deutschland

Optical spin manipulation of electrically pumped vertical-cavity surface-emitting lasers

Stephan Hövel, Andreas Bischoff, Nils C. Gerhardt, Martin R. Hofmann , T. Ackemann, A. Kroner, R. Michalzik - Appl. Phys. Lett. 92, 041118

Gain on Silicon: Monolithic integration of GaNAsP on Si

C. Lange, D. Franzbach, S. Chatterjee, W.W. Rühle, B. Kuhnert, I. Németh, S. Zinnkann, R. Fritz, G. Lukin, T.B. Adams, K. Volz, W. Stolz, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - NOEKS, Klink

Spin-controlled optoelectronic devices

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. Wieck, E. Schuster, W. Keune - NOEKS, Klink

Monolithic integration of the novel GaP-based laser material Ga(NAsP) on (001) Si substrate without any dislocation formation

B. Kunert, I. Németh, S. Zinnkann, G. Lukin, T.B. Adams, R. Fritz, K. Volz, W. Stolz, C. Lange, S. Chatterjee, W. Rühle, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - E-MRS Spring Meeting, Strasbourg, France

Optical gain in Ga(NAsP)/(BGa)(AsP) multi-quantum-well heterostructures grown lattice-matched on (001) Silicon substrate

B. Kunert, I. Németh, S. Zinnkann, G. Lukin, T.B. Adams, R. Fritz, K. Volz, W. Stolz, C. Lange, N.S. Koester, D.J. Franzbach, S. Chatterjee, W. Rühle, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - Device Research Conference, University of California, Santa Barbara, USA

Optical verification of gain in Ga(NAsP)/(BGa)(AsP) multi-quantum-well heterostructures monolithically grown lattice-matched on (001) silicon substrate

B. Kunert, I. Németh, S. Zinnkann, G. Lukin, T.B. Adams, R. Fritz, K. Volz, W. Stolz, C. Lange, N.S. Koester, D.J. Franzbach, S. Chatterjee, W. Rühle, Nils C. Gerhardt, Nektarios Koukourakis, Martin R. Hofmann - International Symposium on Compound Semiconductors (ISCS) Europa-Park, Rust, Germany

Electrical detection of photoinduced spins both at room temperature and in remanence

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A.D. Wieck, E. Schuster, W. Keune, H. Wende, O. Petracic, K. Westerholt - Appl. Phys. Lett. 92, 242102

Room temperature electrical spin injection in remanence

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , F.-Y. Lo, A. Ludwig, D. Reuter, A. D. Wieck, E. Schuster, H. Wende, W. Keune, O. Petracic, K. Westerholt - Appl. Phys. Lett. 93, 021117

Evaluation of Simplex Codes for Photoacoustic Coded Excitation

Martin P. Mienkina, Eder A., Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc IFMBE, vol 22, pp 444-447

Simulation Study of Photoacoustic Coded Excitation using Golay Codes

Martin P. Mienkina, Eder A., Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc IEEE International Ultrasonics Symposium, 1242-1245

Evaluation of Simplex Codes for Photoacoustic Coded Excitation

Martin P. Mienkina, Annika Eder, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann , Georg Schmitz - Proc. IFMBE, vol 22, 2008, pp 444-447

Simulation Study of Photoacoustic Coded Excitation using Golay Codes

Martin P. Mienkina, Annika Eder, Georg Schmitz, Claus-Stefan Friedrich, Nils C. Gerhardt, Martin R. Hofmann - Proc. IEEE International Ultrasonics Symposium, 2008, 1242-1245

Spin-controlled LEDs and VCSELs

Stephan Hövel, Nils C. Gerhardt, Carsten Brenner, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A.D. Wieck, E. Schuster, W. Keune - Phys. Stat. Sol. A 204, 500

Micromirror device controlled tunable diode laser

Michael Breede, Christoph Kasseck, Carsten Brenner, Nils C. Gerhardt, Martin R. Hofmann , R. Höfling - Electron. Lett. 43, 456

Photoacoustic Imaging of Fibrosarcoma using RGD-Cy 3 as a Targeted Contrast Agent

Martin P. Mienkina, Claus-Stefan Friedrich, Nils C. Gerhardt, J. Waldeck, Karin Hensel, C. Bremer, Martin R. Hofmann , Georg Schmitz - Proc IEEE International Ultrasonics Symposium 0, 2409

Spectroscopic Fourier Domain Optical Coherence Tomography

Christoph Kasseck, Kirsten Lehmann, Nils C. Gerhardt, Martin R. Hofmann - SPIE Europe, European Conference on Biomedical Optics, Munich, Germany

Evaluation eines kommerziellen Ultraschallgeräts für den Einsatz im photoakustischen Reflexionsmodus

Martin P. Mienkina, Nils C. Gerhardt, J. Waldeck, Michael Breede, C. Bremer, Martin R. Hofmann , Georg Schmitz - Biomedizinische Technik 52, G2-1

Spectroscopic Fourier Domain Optical Coherence Tomography

Christoph Kasseck, Kirsten Lehmann, Nils C. Gerhardt, Martin R. Hofmann - SPIE Proceedings 6627-67

External-cavity diode laser utilizing a micromirror device for spectral tuning

Michael Breede, Christoph Kasseck, Carsten Brenner, Nils C. Gerhardt, R. Höfling, Martin R. Hofmann - SPIE Europe, Optical Metrology, Munich, Germany

The variable stripe-length method revisited: Improved analysis

C. Lange, M. Schwalm, S. Chatterjee, W. W. Rühle, Nils C. Gerhardt, S. R. Johnson, J.-B. Wang, Y.-H. Zhang - Appl. Phys. Lett. 91, 191107

External-cavitydiode laser utilizing a micromirror device for spectral tuning

Michael Breede, Christoph Kasseck, Carsten Brenner, Nils C. Gerhardt, R. Höfling, Martin R. Hofmann - Proc SPIE 6616, 66160R

Evaluation eines kommerziellen Ultraschallgeräts für den Einsatz im photoakustischen Reflexionsmodus

Martin P. Mienkina, Nils C. Gerhardt, Jens Waldeck, Michael Breede, Christoph Bremer, Martin R. Hofmann , Georg Schmitz - Biomedical Engineering, Vol 52 (2007, Suppl), G2-1

Photoacoustic Imaging of Fibrosarcoma using RGD-Cy 3 as a Targeted Contrast Agent

Martin P. Mienkina, Claus-Stefan Friedrich, Jens Waldeck, Karin Hensel, Nils C. Gerhardt, C. Bremer, Martin R. Hofmann , Georg Schmitz - Proc. IEEE International Ultrasonics Symposium, 2007, pp 2409-2412

Enhancement of spin information with vertical cavity surface emitting lasers

Nils C. Gerhardt, Stephan Hövel, Martin R. Hofmann , J. Yang, D. Reuter, A. Wieck - Electronics Letters 42, 88

Spin injection light-emitting diode with vertically magnetized ferromagnetic metal contacts

Nils C. Gerhardt, Stephan Hövel, Carsten Brenner, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A.D. Wieck, E. Schuster, W. Keune, S. Halm, G. Bacher, K. Westerholt - Journal of Applied Physics 99, 073907-1

Spin-controlled vertical cavity surface-emitting lasers

Stephan Hövel, Nils C. Gerhardt, Carsten Brenner, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. D. Wieck, E. Schuster, W. Keune - Photonics Europe, Strasbourg, France (invited)

Spin-controlled LEDs and VCSELs

Stephan Hövel, Nils C. Gerhardt, Carsten Brenner, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. Wieck, E. Schuster, W. Keune - ICSNN, Istanbul, Turkey (invited)

Spin-controlled vertical cavity surface-emitting lasers

Stephan Hövel, Nils C. Gerhardt, Carsten Brenner, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. D. Wieck, E. Schuster, W. Keune - Proc. SPIE 6184, 61840Y

Lasing in optically pumped Ga(NAsP)/GaP heterostructures

S. Borck, S. Chatterjee, B. Kunert, K. Volz, W. Stolz, J. Heber, W. W. Rühle, Nils C. Gerhardt, Martin R. Hofmann - Appl. Phys. Lett. 89, 031102

Experimental Characterization of Ferucarbotran as a Photoacoustic Contrast Agent

Martin P. Mienkina, Karin Hensel, Tuyen N. Le, Nils C. Gerhardt, Ch. Hansen, Martin R. Hofmann , Georg Schmitz - Proc IEEE International Ultrasonics Symposium 0, 393

Experimentelle Charakterisierung von Ferucarbotran als photoakustisches Kontrastmittel

Martin P. Mienkina, Karin Hensel, Tuyen N. Le, Nils C. Gerhardt, E. Bründermann, M. Havenith, Martin R. Hofmann , Georg Schmitz - Proc Gemeinsame Jahrestagung der Deutschen, Österreichischen und Schweizerischen Gesellschaften für Biomedizinische Technik 51, V180

Experimental Characterization of Ferucarbotran (Resovist ®) as a Photoacoustic Nanoparticle Contrast Agent

Martin P. Mienkina, Karin Hensel, L. N. Tuyen, Nils C. Gerhardt, Christian Hansen, Martin R. Hofmann , Georg Schmitz - Proc IEEE International Ultrasonics Symposium, 2006, pp 393-396

Experimentelle Charakterisierung von Ferucarbotran als photoakustisches Kontrastmittel

Martin P. Mienkina, Karin Hensel, Tuyen N. Le, Nils C. Gerhardt, Ilona Kopf, Erik Bründermann, Martina Havenith, Martin R. Hofmann , Georg Schmitz - Biomedical Engineering, Vol 51 (2006 Suppl), V180

Spin controlled optically pumped vertical cavity surface emitting laser

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , J. Yang, D. Reuter, A. Wieck - Electronics Letters 41, 251

Spin-controlled LEDs and VCSELs

Nils C. Gerhardt, Stephan Hövel, Carsten Brenner, Martin R. Hofmann , J. Yang, D. Reuter, A. D. Wieck - Proc. SPIE 5722, 221

Spin-controlled LEDs and VCSEL s

Nils C. Gerhardt, Stephan Hövel, Carsten Brenner, Martin R. Hofmann , J. Yang, D. Reuter, A. D. Wieck - SPIE Photonics West, San Jose, California, USA

Electron spin injection into GaAs from ferromagnetic contacts in remanence

Nils C. Gerhardt, Stephan Hövel, Carsten Brenner, Martin R. Hofmann , F.-Y. Lo, D. Reuter, A. D. Wieck, E. Schuster, W. Keune, K. Westerholt - Appl. Phys. Lett. 87, 032502

Spin dependent polarisation of optically pumped VCSELs

Stephan Hövel, Nils C. Gerhardt, Martin R. Hofmann , J. Yang, D. Reuter, A. D. Wieck - SIOE, Cardiff, Wales

Linewidth enhancement factor and optical gain in (GaIn)(NAs)/GaAs lasers

Nils C. Gerhardt, Martin R. Hofmann , J. Hader, J.V. Moloney, S.W. Koch, H. Riechert - Appl. Phys. Lett. 84, 1

Gain and emission dynamics of (GaIn)(NAs) lasers

Martin R. Hofmann , Nils C. Gerhardt - 2nd International Workshop on Metastable Compound Semiconductors and Heterostructures, Marburg, Germany

Experimental analysis of the optical gain and linewidth enhancement factor of GaInNAs/GaAs lasers

Nils C. Gerhardt, Martin R. Hofmann - J. Phys.: Condens. Matter 16, S3095 (2004) - invited

Optical spectroscopy of 1.3 µm (GaIn)(NAs)/GaAs lasers

Nils C. Gerhardt, Martin R. Hofmann , W.W. Rühle - IEEE Proceedings Optoelectronics 150, 45

Gain and emission dynamics of dilute nitride quantum well lasers

Martin R. Hofmann , Nils C. Gerhardt - Annual Meeting Optical Society of America, Tucson, Arizona, USA (invited)

Gain and emission dynamics of dilute nitride Gain quantum well lasers

Martin R. Hofmann , Nils C. Gerhardt - IEEE JOURNAL OF QUANTUM ELECTRONICS, Volume: 38 Issue: 2 Pages: 213-221 Published: FEB 2002

Optical gain of 1.3 µm (GaIn)(NAs)/GaAs lasers: a comparison between theory and experiment

Nils C. Gerhardt, Martin R. Hofmann , W. Stolz, S.W. Koch, J. Hader, J.V. Moloney, A. Yu. Egorov, H. Riechert - SIOE, Cardiff, Wales

Optical gain of 1.3 µm (GaIn)(NAs)/GaAs lasers

Nils C. Gerhardt, Martin R. Hofmann - International Research Workshop on The Physics and Technology of Dilute Nitrides for Optical Communications, Istanbul, Türkei (invited)

Emission dynamics and optical gain of 1.3 µm (GaIn)(NAs)/GaAs lasers

Martin R. Hofmann , Nils C. Gerhardt, A. Wagner, C. Ellmers, F. Höhnsdorf, J. Koch, W. Stolz, S.W. Koch, W.W. Rühle, J. Hader, J. V. Moloney, E.P. O'Reilly, B. Borchert, A. Yu. Egorov, H. Riechert, H.C. Schneider, W.W. Chow - IEEE J. Quantum Electron. 38, 213

Influence of growth conditions on the optical gain of 1.3 µm (GaIn)(NAs)/GaAs lasers

Nils C. Gerhardt, Martin R. Hofmann , K. Handtke, W. Stolz, S.W. Koch, J. Hader, J.V. Moloney, A. Yu. Egorov, H. Riechert - International Semiconductor Laser Conference, Garmisch-Partenkichen, Germany

Physics of 1.3 µm (GaIn)(NAs)/GaAs semiconductor lasers

Martin R. Hofmann , Nils C. Gerhardt, Wagner, A., Stolz, W., Koch, S. W., Rühle, W. W., Hader, J. - 14th Annual Meeting of the IEEE, LEOS 2001, Lasers and Electro-Optics Society, Jahr 2002, H 1, S. 326-327

Spintronic: Spin electronics and optoelectronics in semiconductors

M. Oestreich, J. Hübner, D. Hägele, M. Bender, Nils C. Gerhardt, Martin R. Hofmann , W.W. Rühle, H. Kalt, T. Hartmann, P. Klar, W. Heimbrodt, W. Stolz - Festkörperprobleme 41, 173

Emission dynamics of (GaIn)(NAs)/GaAs lasers emitting at 1.3 µm

Martin R. Hofmann , A. Wagner, Nils C. Gerhardt, C. Ellmers, F. Höhnsdorf, J. Koch, S. Leu, W. Stolz, W. W. Rühle - Proc. SPIE 4283, 256 (2001) - invited

Physics of 1.3 µm (GaIn)(NAs)/GaAs lasers

Martin R. Hofmann , Nils C. Gerhardt, A. Wagner, W. Stolz, S.W. Koch, W.W. Rhle, J. Hader, J. V. Moloney - LEOS, San Diego, USA (invited)

Gain of 1.3 µm (GaIn)(NAs)/GaAs lasers, Workshop on novel gain materials

Martin R. Hofmann , Nils C. Gerhardt, A. Wagner, C. Ellmers, F. Höhnsdorf, J. Koch, S. Leu, W. Stolz, S.W. Koch, W.W. Rühle, B. Borchert, A. Yu. Egorov, H. Riechert - Würzburg, Germany

Emission dynamics and gain of (GaIn)(NAs)/GaAs lasers

Nils C. Gerhardt, A. Wagner, C. Ellmers, F. Höhnsdorf, J. Koch, W. Stolz, Martin R. Hofmann , S.W. Koch, W.W. Rühle, J. Hader , J.V. Moloney - Microcavity and Photonics Workshop, Ascona, Schweiz

Photonik und Terahertztechnologie

Chair

Dr. Nils C. Gerhardt

Address

projects

Courses

Publications