FEASIBILITY STUDIES IN HIGH RESOLUTION THz SPECTROSCOPY CHRISTIAN ENDRES FRANK LEWEN MARTINA WIEDNER OLIVER RICKEN URS GRAF THOMAS GIESEN STEPHAN SCHLEMMER I. PHYSIKALISCHES INSTITUT UNIVERSITY OF COLOGNE GERMANY DMITRY PAVELIEV LABORATORY OF SEMICONDUCTOR DEVICES RADIOPHYSICAL FACULTY STATE UNIVERSITY OFNIZHNY NOVGOROD RUSSIA

Atacama Pathfinder Experiment APEX 280 – 890 GHz (1.3 – 1.5 THz) Herschel Space Observatory HIFI / Herschel 0.5 – 1.25 THz and 1.4 – 1.9 THz Start Feb 2009 ALMA Atacama Large Millimeter Array 84 – 720 GHz (30 – 950 GHz) Start ~ 2011 New Telescopes for Sub-mm Astronomy

PLL Harmonic Mixer PC Lock-InSynthesizer Power Supply Synthesizer IF 350 MHz16 GHz 2f Modulation ~ GHz Bolometer Absorption cell Lense Cologne Terahertz Spectrometer Atomic Clock Frequency Range: up to 1 THz Accuracy  =10 -9

PLL Harmonic Mixer PC Lock-InSynthesizer SL Power Supply Synthesizer IF 350 MHz16 GHz 2F Modulation ~250 GHz 0.75 – 3.1 THz Bolometer Absorption cell Lense Application of Superlattice Multipliers for High Resolution THz Spectroscopy, C. P. Endres, F. Lewen, T. F. Giesen, and S. Schlemmer, Rev. Scientific Instr. (2007) I. Cologne Superlattice Spectrometer for 0.25 – 3.1 THz

Superlattice Multiplier Development and Fabrication D.Paveliev (N. Novgorod State University) K.F.Renk (Universität Regensburg) Periodic Structure 14 monolayers GaAs / 3 monolayers AlAs 70 Periods in total Output Power: ~ 0.5 mW, 3 rd harmonic Efficiency > 5% for 3 rd harmonic Frequency ~ 300 – 3000 GHz Structure Performance 14 mono GaAs 70 periods 3 mono AlAs Superlattice Diodes for 0.3 – 3.0 THz Current-Voltage Curve

3 rd,5 th,7 th, and 9 th harmonics of 100 GHz Input Methanol at 337, 501, 767, and 1062 GHz x3x3 x5x5 x9x9 x7x7

Output Power of Schottky and Superlattice Multipliers Application of Superlattice Multipliers for High Resolution THz Spectroscopy, C. P. Endres, F. Lewen, T. F. Giesen, and S. Schlemmer, Rev. Scientific Instr. (2007) Fundamental = 115 GHz 3 rd 7 th 5 th 9 th a = 10 log (U/U 0 ) a SL =0.053 dB/GHz a SK =0.080 dB/GHz 11 th

Cologne SL-Terahertz Spectrometer 11 th harmonic of 220 GHz input ND 2 H

J Ka Kc = – EA AE EE AA Broadband Tunability Spectrum of Dimethyl Ether

II. SL-Heterodyne Receiver at Room Temperature SL Absorption Cell SL Synthesizer 25 GHz x 4 Synthesizer 15 GHz 100 GHz 300 GHz 500 GHz 700 GHz 900 GHz 1100 GHz IF = 350 MHz = (300-19x15.771) GHz = (500-35x…) GHz Synthesizer MHz IF = 50 KHz ~ Bandpass ~ Multimeter IF = 350 MHz Atomic Clock

II. SL-Heterodyne Receiver at Room Temperature SL Absorption Cell SL Synthesizer 25 GHz x 4 Synthesizer 15 GHz 100 GHz 300 GHz 500 GHz 700 GHz 900 GHz 1100 GHz IF = 350 MHz = (300-19x15.771) GHz = (500-35x…) GHz Synthesizer MHz IF = 50 KHz ~ Bandpass ~ Multimeter IF = 350 MHz Atomic Clock All solid state spectrometer Sensitive Heterodyne Detection

x 50 J ka kc = – CH 3 -O-CH 3 DME Spectrum at 301 GHz Sample of 30 scans, Integration time: 60 sec  I / I = 2x rd Harmonics

5 th Harmonics J ka kc = – DME Spectrum at 503 GHz

III. 1.5 THz CONDOR Heterodyne Receiver Emission Spectroscopy Martin Puplett HEB Multiplier Chain 1.5 THz, 1µW IF = 1- 4 GHz AOS Liq. N 2 D2OD2O M. Wiedner et al. Astron. Astrophys., 454, L33-L36 (2006)

D 2 O Heterodyne Spectrum at 1.5 THz Emission Line

SL Martin Puplett HEB Gunn GHz 90 GHz Multiplier Chain 1.5 THz, 1mW IF = 1- 4 GHz 17 th harmonics 20 pW 1.5 THz AOS D2OD2O III. 1.5 THz CONDOR Heterodyne Receiver Absorption Spectroscopy with SL Multiplier Source

D 2 O Heterodyne Signal at 1.5 THz Absorption using the 17 th harmonics of a Superlattice p=20  bar

Specifications: PowerSupply: 0.7 A, 4.4 V Power dissipation: 3 W Operation Temp: 20 K Single Mode Conditions for 1.5 THz QCL 1.5 THz QCL Developement C.Walther, M. Fischer, N. Hoyler, J. Faist Institut f¨ur Quantenelektronik, ETH Zürich, Switzerland Mode operation

IV. First Phase Locked QCL at 1.5 THz SL Martin Puplett HEB Gunn 122 x 2 GHz 244 GHz IF = 200 MHz PLL 6 th harmonics 1.5 THz QCL Referenz 1-2 mW 1.5 THz U.Graf, M. Philipp, O. Ricken, B. Vowinkel, M.C. Wiedner, C. Walther, M.Fischer, N.Hoyler, J. Faist, 2008

1.5 THz Phase Locked Quantum Cascade Laser 1 KHz

New low current Quantum Cascade Lasers at 1.9 THz J. Faist et al, Neuchatel

Low Temperature 22-Pole Ion- Trap

Ion Trap: Experimental Setup cold head 10 K 22 pole Ion trap

Potential Energy Surface Reactants Association Products Transition State E kT AB + + C A + + BC

Potential Energy Surface Reactants Association Products Transition State E kT A +* + BC AB + + C AB +* + C A + + BC h

Energy Level Diagram of H 2 D +

H3+H3+ H2D+H2D K 100 K X p-H 3 + o-H 3 + p-H 2 D + o-H 2 D + Reaction Laser Induced Reactions probing H 2 D + + HD + H 2

H3+H3+ H2D+H2D K 100 K X p-H 3 + o-H 3 + p-H 2 D + o-H 2 D + Laser Enhanced Reaction h Laser Induced Reactions probing H 2 D + + HD + H 2

New Results H2D+H2D+ Δ = 62 MHz (!) APEX  = 20 kHz (!) (!) Phys. Rev. Lett. 100, (2008) Thursday, June19 RB10, Müller et al

Summary I.Superlattice Spectrometer for GHz II.Superlattice Heterodyne Spectrometer for room temperature operation III.1.5 THz Heterodyne Emission and Absorption Spectroscopy IV.First 1.5 THz phase locked Quantum cascade laser V.Ultrasensitive Ion Spectroscopy at 1.5 THz

Output Power of higher Harmonics of a Superlattice Multiplier