Bingxin Xu, Zaijun Chen, Theodor W. Hänsch, N. Picqué,
Abstract Ultraviolet spectroscopy provides unique insights into the structure of matter with applications ranging from fundamental tests to photochemistry in the Earth’s atmosphere and astronomical observations from space telescopes 1–8 . At longer wavelengths, dual-comb spectroscopy, using two interfering laser frequency combs, has become a powerful technique capable of simultaneously providing a broad spectral range and very high resolution 9 . Here we demonstrate a photon-counting approach that can ...
Tópico(s): Mass Spectrometry Techniques and Applications
2024 - Nature Portfolio | Nature
Matthias Arend, Jörg‐Peter Schnitzler, Barbara Ehlting, Robert Hänsch, Theodor Lange, Heinz Rennenberg, Axel Himmelbach, Erwin Grill, Jörg Fromm,
The consequences of altered abscisic acid (ABA) sensitivity in gray poplar (Populus × canescens [Ait.] Sm.) development were examined by ectopic expression of the Arabidopsis (Arabidopsis thaliana) mutant abi1 (for abscisic acid insensitive1) gene. The expression resulted in an ABA-insensitive phenotype revealed by a strong tendency of abi1 poplars to wilt, impaired responsiveness of their stomata to ABA, and an ABA-resistant bud outgrowth. These plants therefore required cultivation under very humid conditions ...
Tópico(s): Plant nutrient uptake and metabolism
2009 - Oxford University Press | PLANT PHYSIOLOGY
F Kaesen, C Fink, K.G. Anil, W. Hänsch, Theodor Doll, T. Grabolla, Horst Schreiber, I. Eisele,
Tópico(s): Silicon Carbide Semiconductor Technologies
1998 - Elsevier BV | Thin Solid Films
... an invention that changed our lives Theodor W. Hänsch, Theodor W. HänschSearch for more papers by this author Theodor W. Hänsch, Theodor W. HänschSearch for more papers by this author ...
Tópico(s): Laser Design and Applications
2010 - Wiley | Laser & Photonics Review
... Get Citation Copy Citation Text Nathalie Picqué and Theodor W. Hänsch, "Mid-IR Spectroscopic Sensing," Optics & Photonics News 30( ...
Tópico(s): Photonic and Optical Devices
2019 - Optica Publishing Group | Optics and Photonics News
... by Roy J. Glauber, John L. Hall, and Theodor W. Hänsch. This lecture is the text of Dr. Hänsch' ...
Tópico(s): Mass Spectrometry Techniques and Applications
2006 - American Physical Society | Reviews of Modern Physics
... to three scientists: Roy Glauber, John Hall and Theodor Hänsch. Roy Glauber succeeded in describing a general method ...
Tópico(s): Quantum optics and atomic interactions
2006 - Wiley | ChemPhysChem
... Constant: A Fundamental Constant Johannes Robert Rydberg, 1890 * Theodor Hansch, 1992 20. The Abundance of Deuterium: A Check ...
Tópico(s): Biofield Effects and Biophysics
2002 - Association of College and Research Libraries | Choice Reviews Online
Claude Cohen‐Tannoudji, William D. Phillips,
... kinetic energy. Laser cooling was suggested independently by Theodor Hänsch and Arthur Schawlow for neutral atoms and by ...
Tópico(s): Quantum Electrodynamics and Casimir Effect
1990 - AIP Publishing | Physics Today
Edoardo Vicentini, Zhenhai Wang, Kasper Van Gasse, Theodor W. Hänsch, N. Picqué,
Holography has always held special appeal, for it is able to record and display spatial information in three dimensions. Here, we show how to augment the capabilities of digital holography by using a large number of narrow laser lines at precisely-defined optical frequencies simultaneously. Using an interferometer based on two frequency combs of slightly different repetition frequencies and a lens-less camera sensor, we record time-varying spatial interference patterns that generate spectral hypercubes ...
Tópico(s): Advanced Fiber Laser Technologies
2021 - Nature Portfolio | Nature Photonics
Julian J. Krauth, Karsten Schuhmann, Marwan Abdou Ahmed, F. D. Amaro, Pedro Amaro, F. Biraben, Tzu-Ling Chen, D. S. Covita, A. Dax, Marc Diepold, L. M. P. Fernandes, B. Franke, Sandrine Galtier, Andrea L. Gouvea, J. Götzfried, Thomas Graf, Theodor W. Hänsch, Jens Hartmann, M. Hildebrandt, P. Indelicato, L. Julién, K. Kirch, A. Knecht, Yiwei Liu, Jorge Machado, C.M.B. Monteiro, F. Mulhauser, Boris Naar, Tobias Nebel, F. Nez, J.M.F. dos Santos, J. P. Santos, Csilla I. Szabo, D. Taqqu, J.F.C.A. Veloso, Jan Vogelsang, Andreas Voß, Birgit Weichelt, Randolf Pohl, Aldo Antognini, F. Kottmann,
Abstract The energy levels of hydrogen-like atomic systems can be calculated with great precision. Starting from their quantum mechanical solution, they have been refined over the years to include the electron spin, the relativistic and quantum field effects, and tiny energy shifts related to the complex structure of the nucleus. These energy shifts caused by the nuclear structure are vastly magnified in hydrogen-like systems formed by a negative muon and a nucleus, so spectroscopy of these muonic ...
Tópico(s): Nuclear physics research studies
2021 - Nature Portfolio | Nature
Marco Piccardo, Vincent Ginis, Andrew Forbes, Simon Mahler, Asher A. Friesem, Nir Davidson, Haoran Ren, Ahmed H. Dorrah, Federico Capasso, Firehun Tsige Dullo, Balpreet Singh Ahluwalia, Antonio Ambrosio, Sylvain Gigan, Nicolas Treps, Markus Hiekkamäki, Robert Fickler, Michael Kues, David Moss, Roberto Morandotti, Johann Riemensberger, Tobias J. Kippenberg, Jérôme Faist, Giacomo Scalari, N. Picqué, Theodor W. Hänsch, Giulio Cerullo, Cristian Manzoni, L. A. Lugiato, Massimo Brambilla, Lorenzo Columbo, Alessandra Gatti, F. Prati, Abbas Shiri, Ayman F. Abouraddy, Andrea Alù, Emanuele Galiffi, J. B. Pendry, Paloma A. Huidobro,
Our ability to generate new distributions of light has been remarkably enhanced in recent years. At the most fundamental level, these light patterns are obtained by ingeniously combining different electromagnetic modes. Interestingly, the modal superposition occurs in the spatial, temporal as well as spatio-temporal domain. This generalized concept of structured light is being applied across the entire spectrum of optics: generating classical and quantum states of light, harnessing linear and nonlinear ...
Tópico(s): Neural Networks and Reservoir Computing
2021 - IOP Publishing | Journal of Optics
Jeong Hyun Huh, Zaijun Chen, Edoardo Vicentini, Theodor W. Hänsch, N. Picqué,
Time-resolved near-infrared absorption spectroscopy of single non-repeatable transient events is performed at high spectral resolution with a dual-comb interferometer using a continuous-wave laser followed by a single electro-optic amplitude modulator. By sharing high-speed electrical/optical components, our spectrometer greatly simplifies the implementation of dual-comb spectroscopy and it offers a high mutual coherence time, measured up to 50-s, without any active stabilization system and/or data ...
Tópico(s): Spectroscopy and Laser Applications
2021 - Optica Publishing Group | Optics Letters
Produção Nacional
Revisado por pares
Rafael A. Probst, Dinko Milaković, B. Toledo-Padrón, G. Lo Curto, Gerardo Ávila, Anna Brucalassi, B. L. Canto Martins, I. C. Leão, M. Esposito, J. I. Gónzalez Hernández, F. Grupp, Theodor W. Hänsch, H. Kellermann, F. Kerber, Olaf Mandel, A. Manescau, Eszter Pozna, R. Rébolo, J. R. De Medeiros, Tilo Steinmetz, A. Suárez Mascareño, Thomas Udem, Josefina Urrutia, Yuanjie Wu, L. Pasquini, Ronald Holzwarth,
Laser frequency combs (LFCs) are well on their way to becoming the next-generation calibration sources for precision astronomical spectroscopy. This development is considered key in the hunt for low-mass rocky exoplanets around solar-type stars whose discovery with the radial-velocity method requires cm/s Doppler precision. In order to prove such precise calibration with an LFC, it must be compared to another calibrator of at least the same precision. Being the best available spectrograph calibrator, ...
Tópico(s): Laser-Matter Interactions and Applications
2020 - Nature Portfolio | Nature Astronomy
Alexey Grinin, Arthur Matveev, D. C. Yost, Lothar Maisenbacher, Vitaly Wirthl, Randolf Pohl, Theodor W. Hänsch, Thomas Udem,
We have performed two-photon ultraviolet direct frequency comb spectroscopy on the 1S-3S transition in atomic hydrogen to illuminate the so-called proton radius puzzle and to demonstrate the potential of this method. The proton radius puzzle is a significant discrepancy between data obtained with muonic hydrogen and regular atomic hydrogen that could not be explained within the framework of quantum electrodynamics. By combining our result [f1S-3S = 2,922,743,278,665.79(72) kilohertz] with a previous ...
Tópico(s): Spectroscopy and Laser Applications
2020 - American Association for the Advancement of Science | Science
J. I. Gónzalez Hernández, R. Rébolo, L. Pasquini, G. Lo Curto, P. Molaro, E. Caffau, H.‐G. Ludwig, M. Steffen, M. Esposito, A. Suárez Mascareño, B. Toledo-Padrón, Rafael A. Probst, Theodor W. Hänsch, Ronald Holzwarth, A. Manescau, T. Steinmetz, Th. Udem, T. Wilken,
Context. The general theory of relativity predicts the redshift of spectral lines in the solar photosphere as a consequence of the gravitational potential of the Sun. This effect can be measured from a solar disk-integrated flux spectrum of the Sun’s reflected light on Solar System bodies. Aims. The laser frequency comb (LFC) calibration system attached to the HARPS spectrograph offers the possibility of performing an accurate measurement of the solar gravitational redshift (GRS) by observing the ...
Tópico(s): Adaptive optics and wavefront sensing
2020 - EDP Sciences | Astronomy and Astrophysics
We demonstrate single-photon time-domain interference in a new realm. We observe interferences in the photon counting statistics with two separate mode-locked femtosecond lasers of slightly different repetition frequencies, each emitting a comb of evenly spaced spectral lines over a wide spectral span. We exploit the interference pattern for spectroscopic diagnostics over a broad spectral range. An experimental proof-of-concept shows that the emerging technique of high-resolution dual-comb Fourier ...
Tópico(s): Spectroscopy and Laser Applications
2020 - National Academy of Sciences | Proceedings of the National Academy of Sciences
Zaijun Chen, Theodor W. Hänsch, N. Picqué,
Mid-infrared high-resolution spectroscopy has proven an invaluable tool for the study of the structure and dynamics of molecules in the gas phase. The advent of frequency combs advances the frontiers of precise molecular spectroscopy. Here we demonstrate, in the important 3-µm spectral region of the fundamental CH stretch in molecules, dual-comb spectroscopy with experimental coherence times between the combs that exceed half an hour. Mid-infrared Fourier transform spectroscopy using two frequency ...
Tópico(s): Mass Spectrometry Techniques and Applications
2019 - National Academy of Sciences | Proceedings of the National Academy of Sciences
Michele Giunta, M. Fischer, W. Hänsel, Tilo Steinmetz, Maurice Lessing, Simon Holzberger, Carsten Cleff, Theodor W. Hänsch, Michael Mei, Ronald Holzwarth,
Precision measurements represent a cornerstone in fundamental science. The capability of observing and quantifying subtle phenomena and events allows new discoveries and it confirms or confutes the theories describing our understanding of nature. The optical frequency comb, providing hundreds of thousands of phase-locked and evenly spaced laser lines, is one of the most fascinating enabling optical technologies and it is the result of a continuous pursuit for precision. Within the two decades from ...
Tópico(s): Spectroscopy and Laser Applications
2019 - Institute of Electrical and Electronics Engineers | IEEE Photonics Technology Letters
A laser frequency comb is a broad spectrum composed of equidistant narrow lines. Initially invented for frequency metrology, such combs enable new approaches to spectroscopy over broad spectral bandwidths, of particular relevance to molecules. The performance of existing spectrometers — such as crossed dispersers employing, for example, virtual imaging phase array étalons, or Michelson-based Fourier transform interferometers — can be dramatically enhanced with optical frequency combs. A new class of ...
Tópico(s): Mass Spectrometry Techniques and Applications
2019 - Nature Portfolio | Nature Photonics
Thomas Udem, Lothar Maisenbacher, Arthur Matveev, Vitaly Wirthl, Alexey Grinin, Axel Beyer, N. Kolachevsky, Randolf Pohl, D. C. Yost, Theodor W. Hänsch,
Abstract High‐resolution laser spectroscopy serves the purpose of determining the energy difference between states of atoms and molecules with the best possible accuracy. Therefore, one may face the problem of finding the center of a symmetric line within a small fraction of the line width, or one needs to extract the energy difference from an asymmetric line without a uniquely defined center. Multiplets of atomic resonance lines are subject to mutual line pullings and give rise to asymmetric line ...
Tópico(s): Cold Atom Physics and Bose-Einstein Condensates
2019 - Wiley | Annalen der Physik
Zaijun Chen, Ming Yan, Theodor W. Hänsch, N. Picqué,
Abstract Laser frequency combs emit a spectrum with hundreds of thousands of evenly spaced phase-coherent narrow lines. A comb-enabled instrument, the dual-comb interferometer, exploits interference between two frequency combs and attracts considerable interest in precision spectroscopy and sensing, distance metrology, tomography, telecommunications, etc. Mutual coherence between the two combs over the measurement time is a pre-requisite to interferometry, although it is instrumentally challenging. ...
Tópico(s): Photonic and Optical Devices
2018 - Nature Portfolio | Nature Communications
Bernardo Casabone, Julia Benedikter, Thomas Hümmer, Franziska Oehl, Karmel de Oliveira Lima, Theodor W. Hänsch, Alban Ferrier, Philippe Goldner, Hugues de Riedmatten, David Hunger,
We report on the coupling of the emission from a single europium-doped nanocrystal to a fiber-based microcavity under cryogenic conditions. As a first step, we study the sample properties and observe a strong correlation between emission lifetime and brightness, as well as a lifetime reduction for nanocrystals embedded in a polymer film. This is explained by differences in the local density of states. We furthermore quantify the scattering loss of a nanocrystal inside the cavity and use this to ...
Tópico(s): Photonic and Optical Devices
2018 - IOP Publishing | New Journal of Physics
Julia Benedikter, Hanno Kaupp, Thomas Hümmer, Yuejiang Liang, Alexander Bommer, Christoph Becher, Anke Krueger, Jason M. Smith, Theodor W. Hänsch, David Hunger,
Sources of individual photons have applications in quantum cryptography, computation, and metrology, but truly scalable sources are still needed. The authors couple silicon-vacancy centers to a high-$Q$ microcavity, yielding a room-temperature source with the potential for high efficiency, brightness, and spectral purity. This setup improves spectral density by more than two orders of magnitude and could offer single-photon rates above 1 GHz, as well as generation of indistinguishable photons.
Tópico(s): Quantum Information and Cryptography
2017 - American Physical Society | Physical Review Applied
Randolf Pohl, F. Nez, Thomas Udem, Aldo Antognini, Axel Beyer, Hélène Fleurbaey, Alexey Grinin, Theodor W. Hänsch, L. Julién, F. Kottmann, Julian J. Krauth, Lothar Maisenbacher, Arthur Matveev, F. Biraben,
We give a pedagogical description of the method to extract the charge radii and Rydberg constant from laser spectroscopy in regular hydrogen (H) and deuterium (D) atoms, that is part of the CODATA least-squares adjustment (LSA) of the fundamental physical constants. We give a deuteron charge radius from D spectroscopy alone of 2.1415(45) fm. This value is independent of the measurements that lead to the proton charge radius, and five times more accurate than the value found in the CODATA Adjustment ...
Tópico(s): Radioactive Decay and Measurement Techniques
2017 - IOP Publishing | Metrologia
Johannes Weitenberg, Andreas Vernaleken, Jan Schulte, Akira Ozawa, Thomas Sartorius, Vladimir Pervak, Hans-Dieter Hoffmann, Thomas Udem, P. Rußbüldt, Theodor W. Hänsch,
We demonstrate nonlinear pulse compression by multi-pass cell spectral broadening (MPCSB) from 860 fs to 115 fs with compressed pulse energy of 7.5 µJ, average power of 300 W and close to diffraction-limited beam quality. The transmission of the compression unit is >90%. The results show that this recently introduced compression scheme for peak powers above the threshold for catastrophic self-focusing can be scaled to smaller pulse energies and can achieve a larger compression factor than previously ...
Tópico(s): Photonic Crystal and Fiber Optics
2017 - Optica Publishing Group | Optics Express
Kathrin J. Mohler, Bernhard J. Bohn, Ming Yan, Gwenaëlle Mélen, Theodor W. Hänsch, N. Picqué,
We extend the technique of multiplex coherent Raman spectroscopy with two femtosecond mode-locked lasers to oscillators of a pulse repetition frequency of 1 GHz. We demonstrate a spectra of liquids, which span 1100 cm-1 of Raman shifts. At a resolution of 6 cm-1, their measurement time may be as short as 5 μs for a refresh rate of 2 kHz. The waiting period between acquisitions is improved 10-fold compared to previous experiments with two lasers of 100-MHz repetition frequencies.
Tópico(s): Spectroscopy and Laser Applications
2017 - Optica Publishing Group | Optics Letters
Samuel A. Meek, Arthur Hipke, G. Guelachvili, Theodor W. Hänsch, N. Picqué,
Sub-Doppler broadband multi-heterodyne spectroscopy is proposed and experimentally demonstrated. Using two laser frequency combs of slightly different repetition frequencies, we have recorded Doppler-free two-photon dual-comb spectra of atomic rubidium resonances of a width of 6 MHz, while simultaneously interrogating a spectral span of 10 THz. The atomic transitions are uniquely identified via the intensity modulation of the observed fluorescence radiation. To the best of our knowledge, these results ...
Tópico(s): Laser-Matter Interactions and Applications
2017 - Optica Publishing Group | Optics Letters
Axel Beyer, Lothar Maisenbacher, Arthur Matveev, Randolf Pohl, K. Yu. Khabarova, Alexey Grinin, Tobias P. Lamour, D. C. Yost, Theodor W. Hänsch, N. Kolachevsky, Thomas Udem,
At the core of the "proton radius puzzle" is a four-standard deviation discrepancy between the proton root-mean-square charge radii (rp) determined from the regular hydrogen (H) and the muonic hydrogen (µp) atoms. Using a cryogenic beam of H atoms, we measured the 2S-4P transition frequency in H, yielding the values of the Rydberg constant R∞ = 10973731.568076(96) per meterand rp = 0.8335(95) femtometer. Our rp value is 3.3 combined standard deviations smaller than the previous H world data, but in good ...
Tópico(s): Advanced Chemical Physics Studies
2017 - American Association for the Advancement of Science | Science
Ming Yan, Pei-Ling Luo, Kana Iwakuni, G. Millot, Theodor W. Hänsch, N. Picqué,
Absorption spectroscopy of fundamental ro-vibrational transitions in the mid-infrared region provides a powerful tool for studying the structure and dynamics of molecules in the gas phase and for sensitive and quantitative gas sensing. Laser frequency combs permit novel approaches to perform broadband molecular spectroscopy. Multiplex dual-comb spectroscopy without moving parts can achieve particularly high speed, sensitivity and resolution. However, achieving Doppler-limited resolution in the mid- ...
Tópico(s): Photonic and Optical Devices
2017 - Springer Nature | Light Science & Applications