Dr. Jens W. Tomm
+49 30 6392 1453
Member of Projects: 3.2
High-power semiconductor lasers are the most efficient man-made light sources, and can convert more than 80% electric energy into light. Currently emission powers of one kW continuous-wave powers are extracted from a single monolithic semiconductor array. Such operation, however, is connected with very high internal power densities of more than 1010 W/cm3. We are interested in the intrinsic limitations of such optoelectronic devices in terms of output power and beam quality (brightness). For this purpose we analyze devices, but also their components such as surfaces and interfaces or gain materials such as quantum wells, superlattices and quantum dots.
For our experiments, we use optical tools, in particular transient spectroscopy that represents a generic competence of MBI. Such work is naturally carried out as collaborative work with device vendors, who provide us with high-quality industry-grade devices and structures. In BMBF-projects such as BlauLas, we work together with Osram OS (Regensburg), Dilas GmbH (Mainz) and Laserline GmbH (Mülheim) or in the frame of bilateral research contracts with Lumentum (Santa Clara) and 3S-Photonics (Nozay).
Beginning in 2014, the material basis of the investigated devices underwent a transition from infrared-emitting GaAs-based devices towards GaN-based wide-bandgap devices emitting in the ultraviolet to green spectral regions. This new field involves a lot of new challenges and opportunities and we are looking forward this work.
Side-view thermal images from a GaN-device before (top) and during (bottom) a Catastrophic Optical Damage (COD) event that takes place on a nanosecond timescale. The color signature in the second image represents hot material ejected out of the device. The cavity of the device (right part) is 1.2 mm in length. The 10 white dots on top of the cavity are the bond wires.
||Visitor at the RIKEN-Institute Sendai, Japan
Senior researcher and project coordinator at MBI
||Visiting professor at Georgia Tech Atlanta
||R&D group leader in a subcontract "Optical characterization of II-VI materials for IR quantum detector fabrication".
||R&D work in a subcontract to "Carl Zeiss Jena" company to develop diode lasers for an IR diode laser spectrometer.
||PhD student, Dr. rer. nat. in Physics, summa cum laude, Humboldt University, Berlin 1984 Dissertation: Study of the optical properties of n-Pb1-xSnxTe/p-Pb1-xSnxTe/p-PbTe-heterostructures by means of photoluminescence and injection-luminescence.
||Physics studies, Diploma in Physics summa cum laude, Humboldt University, Berlin 1982 Thesis: Luminescence properties of lead salts for optical and electrical excitation.
Further scientific activities
Reviewer in about three dozen scientific journals and several governmental organizations
Member in several committees of international conferences such as CLEO Europe; EMRS, ISROS, ESREF, and DRIP, Organizer of several conferences: DRIP-XII, see http://www.drip12.de/, Symposium Chair at EMRS-Spring Meetings “Semiconductor nanostructures towards electronic and optoelectronic device applications I-VI in 2007, 2009, 2011, 2013, 2015, 2017
Member of the E-MRS Executive Committee 2014-2016
Member of the “Optical Society of America” and "German Physical Society"
~300 publications in peer-reviewed journals, 3 review articles, two books, edited several volumes as guest editor of journals (conference proceedings)
Associate Editor for the “Journal of Electronic Materials” (JEMS) starting in 2015, and member of the Editorial Board of “Communications in Physics” (CIP) starting in 2016
Project leader and contributor in many national (BMBF; DFG, Volkswagen) and international (3 Integrated EU Projects, ESA) research projects
Cooperation with industry within the frame of bilateral contracts or projects
Member of the DLRG (German Life Rescue Association), Cycling, Running, Finisher at several marathon contests
Publications at MBI
Juan Jiménez and Jens W. Tomm, "Spectroscopic Analysis of Optoelectronic Semiconductors", Springer Series in Optical Sciences Vol. 202 (Springer, 2016).
Jens W. Tomm and Juan Jiménez, "Quantum-Well Laser Array Packaging", Nanoscience and Technology Series (McGraw-Hill, 2007).
Selected publication from the last decade
 Claus Ropers, Tran Quoc Tien, Christoph Lienau, and Jens W. Tomm, Peter Brick, Norbert Linder, Bernd Mayer, Martin Müller, Sönke Tautz, and Wolfgang Schmid “Observation of deep level defects within the waveguide of red-emitting high-power diode lasers” Appl. Phys. Lett. 88, 133513 (2006).
 Jens W. Tomm, Tran Quoc Tien, and Daniel. T. Cassidy, “Spectroscopic strain measurement methodology: Degree-of-polarization photoluminescence vs. photocurrent spectroscopy” Appl. Phys. Lett. 88, 1335504, 1-3 (2006).
 Michael Kreissl, Tran Quoc Tien, Jens W. Tomm, D. Lorenzen, Anna Kozlowska, Mateusz Latoszek, Myriam Oudart, and Julien Nagle, “Spatially-resolved and temperature-dependent thermal tuning rates of high-power diode laser arrays” Appl. Phys. Lett. 88, 133510, 1-3 (2006).
 V. G. Talalaev, G. E. Cirlin, A. A. Tonkikh, N. D. Zakharov, P. Werner, U. Gösele, J.W. Tomm, and T. Elsaesser, “Miniband-related 1.4 – 1.8 µm luminescence of Ge/Si quantum dot superlattices” Nano Res. Lett. DOI 10.1007/s11671-006-9004-x (2006), Nanoscale Research Letters 1, 137-53 (2006).
 Florian Saas, Vadim Talalaev, Uwe Griebner, Jens W. Tomm, Martin Zorn, Andrea Knigge, and Markus Weyers “Optically pumped semiconductor disk laser with graded and stepindex” Appl. Phys. Lett. 89, 151120, 1-3 (2006).
 Tomasz J. Ochalski, Dorota Pierścińska, Kamil Pierściński, Maciej Bugajski, Jens W. Tomm, Tobias Grunske, and Anna Kozlowska “Complementary thermo-reflectance and micro-Raman analysis of facet temperatures of diode lasers” Appl. Phys. Lett. 89, 071104, 1-3 (2006).
 Tran Quoc Tien, Fritz Weik, Jens W. Tomm, Bernd Sumpf, Martin Zorn, Ute Zeimer, and Götz Erbert “Thermal properties and degradation behavior of red-emitting high-power diode lasers” Appl. Phys. Lett. 89, 181112, 1-3 (2006).
 Mathias Ziegler, Fritz Weik, Jens W. Tomm, Thomas Elsaesser, Włodzimierz Nakwaski, Robert P. Sarzała, Dirk Lorenzen, Jens Meusel, Anna Kozłowska, “Transient thermal properties of high-power diode laser bars” Appl. Phys. Lett. 89, 263506 (2006).
 Ramunas Aleksiejunas, Arunas Kadys, Kestutis Jarasiunas, Florian Saas, Uwe Griebner, and Jens W. Tomm “All-optical analysis of carrier and spin relaxation in InGaAs/GaAs saturable absorber structures ” Appl. Phys. Lett. 90, 102105, 1-3 (2007).
 Mathias Ziegler, Tran Quoc Tien, Sandy Schwirzke-Schaaf, Jens W. Tomm, Bernd Sumpf, Götz Erbert, Myriam Oudart, and Julien Nagle, “Gradual degradation of red-emitting high-power diode laser bars”Appl. Phys. Lett. 90, 171113, 1-3 (2007).
 M. Bou Sanayeha, P. Brick, W. Schmid, B. Mayer, M. Müller, M. Reufer, K. Streubel J. W. Tomm, and G. Bacher “Temperature-power dependence of catastrophic optical damage in AlGaInP laser diodes” Appl. Phys. Lett. 91, 041115, 1-3 (2007).
 Mathias Ziegler, Jens W. Tomm, Thomas Elsaesser, Clemens Matthiesen, Marwan Bou Sanayeh, and Peter Brick; “Real-time thermal imaging of catastrophic optical damage in red-emitting high-power diode lasers” Appl. Phys. Lett. 92, 103514, 1-3 (2008).
 Mathias Ziegler, Jens W. Tomm, Thomas Elsaesser, Götz Erbert and Frank Bugge, Włodzimierz Nakwaski, and Robert P. Sarzała, “Visualization of heat flows in high-power diode lasers by lock-in thermography” Appl. Phys. Lett. 92, 103513, 1-3 (2008).
 Mathias Ziegler, Vadim Talalaev, Jens W. Tomm, Thomas Elsaesser, Peter Ressel, Bernd Sumpf, and Götz Erbert, “Surface recombination and facet heating in high-power diode lasers” Appl. Phys. Lett. 92, 203506, 1-3 (2008).
 Mathias Ziegler, Robert Pomraenke, Max Felger, Jens W. Tomm, Parinda Vasa, Christoph Lienau, Marwan Bou Sanayeh, Alvaro Gomez-Iglesias, Martin Reufer, Frank Bugge, and Götz Erbert, "Infrared emission from the substrate of GaAs-based semiconductor lasers" Appl. Phys. Lett. 93, 041101 (2008).
 V. G. Talalaev, J. W. Tomm, N. D. Zakharov, P. Werner, U. Gösele, B. V. Novikov, A. S. Sokolov, Y. B. Samsonenko, V. A. Egorov, and G. E. Cirlin, “Transient carrier transfer in tunnel injection structures” Appl. Phys. Lett. 93, 031105 (2008).
 Mathias Ziegler, Jens W. Tomm, David Reeber, Thomas Elsaesser, Ute Zeimer, Henning E. Larsen, Paul M. Petersen, and Peter E. Andersen “Catastrophic optical mirror damage in diode lasers monitored during single pulse operation” Appl. Phys. Lett. 94, 191101, 1-3 (2009).
 Martin Hempel, Mathias Ziegler, Jens W. Tomm, Thomas Elsaesser, Nicolas Michel, and Michel Krakowski, "Time-resolved analysis of catastrophic optical damage in 975 nm emitting diode lasers," Appl. Phys. Lett. 96 (25), 251105 (2010).
 Mathias Ziegler, Martin Hempel, Henning E. Larsen, Jens W. Tomm, Peter E. Andersen, Sonnik Clausen, Stella N. Elliott, and Thomas Elsaesser, "Physical limits of semiconductor laser operation: A time-resolved analysis of catastrophic optical damage," Appl. Phys. Lett. 97 (2), 021110 (2010).
 Martin Hempel, Jens W. Tomm, Mathias Ziegler, Thomas Elsaesser, Nicolas Michel, and Michel Krakowski “Catastrophic optical damage at front and rear facets of diode lasers” Appl. Phys. Lett. 97, 231101 (2010).
 C. K. Amuzuvi, S. Bull, J. W. Tomm et al., “The impact of temperature and strain-induced band gap variations on current competition and emitter power in laser bars,” Appl. Phys. Lett. 98 (24), 241108 (2011).
 M. Hempel, F. La Mattina, J. W. Tomm et al., “Defect evolution during catastrophic optical damage of diode lasers,” Semiconductor Science and Technology, 26 (7), 075020 (2011).
 M. Hempel, J. W. Tomm, M. Baeumler et al., “Near-field dynamics of broad area diode laser at very high pump levels,” AIP Advances, 1 (4) 042148 1-6 (2011).
 M. Hempel, J. W. Tomm, P. Hennig et al., “Emission properties of diode laser bars during pulsed high-power operation,” Semiconductor Science and Technology, 26 (9) 092001 (1-4) (2011).
 R. Pagano, M. Ziegler, J. W. Tomm et al., “Two-dimensional carrier density distribution inside a high power tapered laser diode,” Appl. Phys. Lett. 98 (22) 221110 (2011).
 J. W. Tomm, M. Ziegler, M. Hempel et al., “Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs-based diode lasers” Laser & Photonics Reviews 5 (3), 422-441 (2011).
 Iwan Moreels, Detlef Kruschke, Peter Glas, and Jens W. Tomm, “The dielectric function of PbS quantum dots in a glass matrix” Opt. Mater. Express, 2 (5) 496-500 (2012).
 Martin Hempel Mathias Ziegler, Sandy Schwirzke-Schaaf, Jens W. Tomm, Denny Jankowski, and Dominic Schröder “Spectroscopic analysis of packaging concepts for high-power diode laser bars” Applied Physics A: Materials Science & Processing 107 (2) 371-377 (2012).
 Martin Hempel, Jens W. Tomm, Vanesa Hortelano, Nicolas Michel, Juan Jiménez, Michel Krakowski, and Thomas Elsaesser “Reconstruction of Defect Creation Sequences in Diode Lasers” Laser & Photonics Reviews, 6 (6), L15-L19 (2012).
 S. Bull, J. J. Lim, C. K. Amuzuvi, J. W. Tomm, J. Nagle, B. Sumpf, G. Erbert, N. Michel, M. Krakowski, and E. C. Larkins “Emulation of the operation and degradation of high-power laser bars using simulation tools” Semiconductor Science and Technology, 27 (9), 094012 (2012).
 M. Hempel, J. W. Tomm, T. Elsaesser, and M. Bettiati, “High single-spatial-mode pulsed power from 980 nm emitting diode lasers” Appl. Phys. Lett. 101 (19), 191105 (2012).
 Fangyu Yue, Jens W. Tomm, Detlef Kruschke, and Peter Glas “Stimulated emission from PbS-quantum dots in glass matrix” Laser & Photonics Reviews, 7 (1), L1-L5 (2013).
 M. Hempel, M. Chi, P. M. Petersen, U. Zeimer, and J. W. Tomm, “How does external feedback cause AlGaAs-based diode lasers to degrade?” Appl. Phys. Lett. 102, 023502 (2013).
 M. Hempel, J. W. Tomm, F. La Mattina, I. Ratschinski, M. Schade, I. Shorubalko, M. Stiefel, H. S. Leipner, F. M. Kiessling, and T. Elsaesser, “Microscopic Origins of Catastrophic Optical Damage in Diode Lasers”, IEEE Journal of Selected Topics in Quantum Electronics 19, 1500508 1 (2013).
 Jens W. Tomm, Martin Hempel, Fabio La Mattina, Frank M. Kießling, and Thomas Elsaesser, “Analysis of bulk and facet failures in AlGaAs-based high-power diode lasers”, Proc. SPIE 8640, 86401F 1 (2013).
 Fangyu Yue, Jens W. Tomm, and Detlef Kruschke, “Spontaneous and stimulated emission dynamics of PbS quantum dots in a glass matrix”, Physical Review B 87, 195314 (2013).
 Fangyu Yue, Jens W. Tomm, Detlef Kruschke, Peter Glas, Kazbek A. Bzheumikhov, and Zaur Ch Margushev, “PbS:Glass as broad-bandwidth near-infrared light source material”, Opt. Express 21, 2287 (2013).
 Sebastian Friede, Sergei Kühn, Jens W Tomm, Veit Hoffmann, Ute Zeimer, Markus Weyers, Michael Kneissl, and Thomas Elsaesser, “Nano-optical analysis of GaN-based diode lasers”, Semiconductor Science and Technology 29, 112001 (2014).
 Kay-Michael Guenther, Thomas Gimpel, Jens W. Tomm, Stefan Winter, Augustinas Ruibys, Stefan Kontermann, and Wolfgang Schade, “Excess carrier generation in femtosecond-laser processed sulfur doped silicon by means of sub-bandgap illumination”, Applied Physics Letters 104, 042107 1 (2014).
 Martin Hempel, Jens W. Tomm, Fangyu Yue, Mauro A. Bettiati, and Thomas Elsaesser, “Short-wavelength infrared defect emission as a probe of degradation processes in 980 nm single-mode diode lasers”, Laser & Photonics Reviews 8, L59 (2014).
 Fangyu Yue, Jens W. Tomm, and D. Kruschke, “Experimental observation of exciton splitting and relaxation dynamics from PbS quantum dots in a glass matrix”, Physical Review B 89, 081303 1 (2014).
 Vadim G. Talalaev, George E. Cirlin, Boris V. Novikov, Bodo Fuhrmann, Peter Werner, and Jens W. Tomm, “Ex post manipulation of barriers in InGaAs tunnel injection devices”, Applied Physics Letters 106, 013104 1 (2015).
 Fangyu Yue, Jens W. Tomm, Detlef Kruschke, Bruno Ullrich, and Junhao Chu, “Temperature dependence of the fundamental excitonic resonance in lead-salt quantum dots”, Applied Physics Letters 107, 022106 1 (2015).
 Martin Hempel, Jens W Tomm, Bernhard Stojetz, Harald König, Uwe Strauss, and Thomas Elsaesser, “Kinetics of catastrophic optical damage in GaN-based diode lasers”, Semiconductor Science and Technology 30, 072001 1 (2015).
 M. Hempel, J. W. Tomm, D. Venables, V. Rossin, E. Zucker, and T. Elsaesser, “Long-Term Aging and Quick Stress Testing of 980-nm Single-Spatial Mode Lasers”, IEEE Journal of Lightwave Technology 33, 4450 (2015).
 S. Dadgostar, J. Schmidtbauer, T. Boeck, A. Torres, O. Martínez, J. Jiménez, J. W. Tomm, A. Mogilatenko, W. T. Masselink, and F. Hatami, “GaAs/GaP quantum dots: Ensemble of direct and indirect heterostructures with room temperature optical emission”, Applied Physics Letters 108, 102103 1 (2016).
 Martin Hempel, Jens Tomm, W. , Alexander Bachmann, Christian Lauer, Michael Furitsch, Uwe Strauß, and Thomas Elsaesser, “Transient surface modifications during singular heating events at diode laser facets”, Semiconductor Science and Technology 31, 055007 1 (2016).
 Robert Kernke, Martin Hempel, Jens W. Tomm, Thomas Elsaesser, Bernhard Stojetz, Harald König, and Uwe Strauß, “Shortwave infrared (SWIR) emission from 450 nm InGaN diode lasers”, Optical Materials Express 6, 2139 (2016).