MBI-Mitarbeiter - Persönliche Daten

Research

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 chip. We are interested in the intrinsic limitations of such optoelectronic devices in terms of output power, beam quality (brightness) and lifetime (reliability). 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. The use of such devices ensures high reproducibility and the chance to get general results, which not depend on the particular device structure that was studied. In BMBF-projects such as BlauLas, we work together with Osram OS (Regensburg), Dilas GmbH (Maiz) and Laserline GmbH (Mülheim) or in the frame of bilateral research contracts with Lumentum (Santa Clara) and 3S-Photonics (Nozay).
The material basis of the investigated devices is now focused to GaN-based wide-bandgap devices emitting in the ultraviolet to blue spectral regions. The figure shows damage patterns as observed in 450-nm emitting high power diode lasers after it experienced the so-called catastrophic optical damage in short-pulse operation.

Subfigure (a) shows the damage patterns at the font facet, where the light leaves the device (red circle), while (b) shows the same region from the side. A channel is visible which burned into the device and ends ~80 µm underneath the front facet; see (c). Subfigure (d) shows the end of this channel in higher resolution. The quantum wells, i.e. the gain medium are well resolved.

 

Curriculum vitae

2018  East China Normal University as ECNU High-End Expert, China

1999  Visitor at the RIKEN-Institute Sendai, Japan

1995 - present: Senior researcher at MBI

1993-1995: Visiting professor at Georgia Tech Atlanta, USA

1986-1989: R&D group leader in a subcontract "Optical characterization of II-VI materials for IR quantum detector fabrication".

1984-1986: R&D work in a subcontract to "Carl Zeiss Jena" company to develop diode lasers for an IR diode laser spectrometer.

1981-1984: 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.

1977-1982: Physics studies, Diploma in Physics summa cum laude, Humboldt University, Berlin 1982 Thesis: Luminescence properties of lead salts for optical and electrical excitation.

MBI Publikationen

  1. Accurate determination of absolute temperatures of GaAs based high-power diode lasers

    M. Ziegler, J. W. Tomm, F. Weik, T. Elsaesser, C. Monte, J. Hollandt, H. Kissel, G. Seibold, J. Biesenbach

    SPIE Proceedings 6876 (2008) 68761A (8pages)
  2. Gradual degradation of red-emitting high-power diode laser bars

    M. Ziegler, T. Q. Tien, S. Schwirzke-Schaaf, J. W. Tomm, B. Sumpf, G. Erbert, M. Oudart, J. Nagle

    Applied Physics Letters 90 (2007) 171113/1-3
  3. Resonances related to an array of InAs quantum dots and controlled by an external electric field

    V. G. Talalaev, B. V. Novikov, A. S. Sokolov, I. V. Strom, J. W. Tomm, N. D. Zakharov, P. Werner, G. E. Cirlin, A. A. Tonkikh

    Semiconductors 41 (2007) 197-204 (Russian original in: Fizika i Tekhnika Poluprovodnikov, 41 (2007) 203-210)
  4. Temperature-power dependence of catastrophic optical damage in AlGalnP laser diodes

    M. B. Sanayeh, P. Brick, W. Schmid, B. Mayer, M. Müller, M. Reufer, K. Streubel, J. W. Tomm, G. Bacher

    Applied Physics Letters 91 (2007) 041115/1-3
  5. Thermal properties of high power laser bars investigated by spatially resolved thermoreflectance spectroscopy

    D. Pierscinska, K. Pierscinski, M. Bugajski, J. W. Tomm

    physica status solidi (a) 204 (2007) 422-429
  6. Chip characterization methods and measurements

    K. Boucke, J. W. Tomm

    High-Power Diode-Lasers: Technology and Applications Springer (2007) 34-47
  7. Processing-induced strains at solder interfaces in extended semiconductor structures

    M. L. Biermann, D. T. Cassidy, T. Q. Tien, J. W. Tomm

    Journal of Applied Physics 101 (2007) 114512/1-5
  8. All-optical analysis of carrier and spin relaxation in InGaAs/GaAs saturable absorber structures

    R. Aleksiejunas, A. Kadys, K. Jarasiunas, F. Saas, U. Griebner, J. W. Tomm

    Applied Physics Letters 90 (2007) 102105/1-3
  9. Observation of deep level defects within the waveguide of red-emitting high-power diode lasers

    C. Ropers, T.Q. Tien, C. Lienau, J.W. Tomm, P. Brick, N. Lindner, B. Mayer, M. Müller, S. Tautz, W. Schmid

    Applied Physics Letters 88 (2006) 133513/1-3
  10. Thermal properties of high power laser bars investigated by spatially resolved thermoreflectance spectroscopy

    D. Pierscinska, K. Pierscinski, M. Bugajski, J. W. Tomm

    Proceedings of 12th International Workshop on Thermal Investigations of ICs, THERMINIC TIMA Editions (2006) 7-11

Andere Publikationen

Books

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).