Milestones - Meilensteine

Terahertz germanium laser system

• E. Bründermann, D.R. Chamberlin, E.E. Haller, High duty cycle and continuous terahertz emission from germanium, Appl. Phys. Lett. 76, 2991-2993 (2000). 
• E. Bründermann et al., Double acceptor doped Ge: A new medium for inter-valence-bandlasers, Appl. Phys. Lett. 68, 3075-3077 (1996).

• 02/2010: Press release Why fish don’t freeze in the Arctic Ocean - RUB chemists unmask natural antifreeze - Anti-freeze protein affects the movement of surrounding water molecules
• 02/2008: Press release Protein Folding Modifies the Water in the Environment - New Knowledge Gained From Terahertz Spectroscopy - RUB Chemists Observes "THz Dance"
• 12/2007: Press release The terahertz dance of water with proteins - Disco becomes a minuet - Protein influence has a previously unsuspected long reach

• 2005: Various spectroscopic sample set-ups: transmission, ATR, cavity enhanced ATR, two-beam.
• 2005: Operated with user interface by students from chemistry and biochemistry with low-tech background.
• 2005: Fully automated LabView controlled germanium laser spectrometer for aquaeous samples.
• 2003: First far-infrared and THz multilayer mirrors for broadband and Q-factor resonators.
• 2001: Simple plug and switch operation. Laser is operational within 30 min after starting the cooler.
• 2001: High duty cycles of large volume (0.3 cm³) high power (Watt) output lasers in closed-cycle cooler up to 2%.
• 2000: Mode-locked copper-doped germanium THz lasers.
• 2000: Very high duty cycles up to 5%, low 4 Watt input power and high 45 kHz repetition rates.
• 2000: Enhanced continuous spontaneous emission indicating continuous wave laser emission for small 0.5 mm³ crystals.
• 1999: Planar lasers: simplifies drastically the fabrication of resonators.
• 1997: With room temperature detection no cryogenic liquid needed.
• 1997: First THz semiconductor laser operation in mobile, small foot-print closed-cycle cooler.
• 1997: Demonstrated wide tuning range from 1 to 4 THz with a single device (unique 160% bandwidth at 2.5 THz).
• 1996: Simple fabrication of Ge THz lasers by diffusing copper into commercially available pure Ge.
• 1996: Deep acceptor doped germanium THz lasers with high duty cycles.
• 1994: Single mode emission of germanium THz laser.
• 1994: Heterodyne detection of laser modes: frequency temperature tuning.
• 1993: Mesh output coupler used as resonator part with germanium THz laser.
• 1992: Ge lasers with narrow linewidth of less than 1 MHz in the 2.5 THz range measured with room temperature Schottky diodes.

Publications using the terahertz germanium laser system:

• S. Ebbinghaus, K. Meister, B. Born, Arthur L. DeVries, M. Gruebele, M. Havenith,
  Antifreeze glycoprotein activity correlates with long-range protein-water dynamics,
  J. Am. Chem. Soc. 132 (35), 12210 (2010). Press release.
• M. Heyden, E. Bründermann, U. Heugen, G. Niehues,  D. M. Leitner, M. Havenith,
  Long range influence of carbohydrates on the solvation dynamics of water – Answers from THz absorption measurements and molecular modeling simulations,
  J. Am. Chem. Soc. 130(17), 5772 (2008).
• S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, M. Havenith,
  Protein sequence- and pH-dependent hydration probed by Terahertz spectroscopy,
  J. Am. Chem. Soc. 130, 2374 (2008).
  
• S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, U. Heugen, M. Gruebele, D. M. Leitner, M. Havenith,
  An extended dynamical solvation shell around proteins,
  PNAS 104, 20749 (2007).
  
• D.M. Leitner, M. Havenith, and M. Gruebele,
  Biomolecule large amplitude motion and solvation dynamics: Modeling and probes from THz to X-rays,
  Intl. Reviews in Physical Chemistry 25, issue 4, 553-582 (2006).
• U. Heugen, G. Schwaab, E. Bründermann, M. Heyden, X. Yu, D.M. Leitner, and M. Havenith,
  Solute induced retardation of water dynamics probed directly by THz spectroscopy,
  PNAS 103, 12301 (2006).
• E. Bründermann, M. Havenith,
  Applications of semiconductor terahertz lasers in biomolecular spectroscopy and imaging,
  Proc. SPIE 6194, 619406 (2006).
• R. Schiwon, G. Schwaab, E. Bründermann, M. Havenith,
  THz cavity enhanced attenuated total reflection spectroscopy,
  Appl. Phys. Lett. 86, 201116 (2005).
• A. Bergner, U. Heugen, E. Bründermann, G. Schwaab, M. Havenith, D.R. Chamberlin, and E.E. Haller,
  New p-Ge THz spectrometer for the study of solutions: THz absorption spectroscopy of water,
  Rev. Sci. Instr. 76, 063110 (2005).