Wittwer, Valentin

2022-4-4, Komagata, Kenichi N., Gianella, Michele, Jouy, Pierre, Kapsalidis, Filippos, Shahmohammadi, Mehran, Beck, Mattias, Matthey-De-L'Endroit, Renaud, Wittwer, Valentin, Hugi, Andreas, Faist, Jérôme, Emmenegger, Lukas, Südmeyer, Thomas, Schilt, Stephane

Optical frequency combs (OFCs) based on quantum cascade lasers (QCLs) have transformed mid-infrared spectroscopy. However, QCL-OFCs have not yet been exploited to provide a broadband absolute frequency reference. We demonstrate this possibility by performing comb-calibrated spectroscopy at 7.7 µm (1305 cm−1) using a QCL-OFC referenced to a molecular transition. We obtain 1.5·10−10 relative frequency stability (100-s integration time) and 3·10−9 relative frequency accuracy, comparable with state-of-the-art solutions relying on nonlinear frequency conversion. We show that QCL-OFCs can be locked with sub-Hz-level stability to a reference for hours, thus promising their use as metrological tools for the mid-infrared.

2013, Sieber, Oliver D, Hoffmann, Martin, Wittwer, Valentin, Mangold, Mario, Golling, Matthias, Tilma, Bauke W, Südmeyer, Thomas, Keller, Ursula

2012, Mangold, Mario, Wittwer, Valentin, Sieber, Oliver D, Hoffmann, Martin, Krestnikov, Igor L, Livshits, Daniil A, Golling, Matthias, Südmeyer, Thomas, Keller, Ursula

2011, Sieber, Oliver D, Wittwer, Valentin, Mangold, Mario, Hoffmann, Martin, Golling, Matthias, Südmeyer, Thomas, Keller, Ursula

2021-6, Komagata, Kenichi N., Shehzad, Atif, Terrasanta, Giulio, Brochard, Pierre, Matthey-De-L'Endroit, Renaud, Gianella, Michele, Jouy, Pierre, Kapsalidis, Filippos, Shahmohammadi Mehran, Mehran, Beck Matthias, Matthias, Wittwer, Valentin, Faist, Jérôme, Emmenegger, Lukas, Südmeyer, Thomas, Hugi, Andreas, Schilt, Stephane

We demonstrate coherent averaging of the multi-heterodyne beat signal between two quantum cascade laser frequency combs in a master-follower configuration. The two combs are mutually locked by acting on the drive current to control their relative offset frequency and by radio-frequency extraction and injection locking of their intermode beat signal to stabilize their mode spacing difference. By implementing an analog common-noise subtraction scheme, a reduction of the linewidth of all heterodyne beat notes by five orders of magnitude is achieved compared to the free-running lasers. We compare stabilization and post-processing corrections in terms of amplitude noise. While they give similar performances in terms of signal-to-noise ratio, real-time processing of the stabilized signal is less demanding in terms of computational power. Lastly, a proof-of-principle spectroscopic measurement was performed, showing the possibility to reduce the amount of data to be processed by three orders of magnitude, compared to the free-running system.

2012, Wittwer, Valentin, Mangold, Mario, Hoffmann, Martin, Sieber, Oliver D, Golling, Matthias, Südmeyer, Thomas, Keller, Ursula

2012, Zaugg, CA, Hoffmann, Martin, Pallmann, Wolfgang P, Wittwer, Valentin, Sieber, Oliver D, Mangold, Mario, Golling, Matthias, Weingarten, Kurt J, Tilma, Bauke W, Südmeyer, Thomas

2013, Wittwer, Valentin, van der Linden, R, Tilma, Bauke W, Resan, B, Weingarten, Kurt J, Südmeyer, Thomas, Keller, Ursula

2012, Pallmann, Wolfgang P, Zaugg, CA, Mangold, Mario, Wittwer, Valentin, Moench, Holger, Gronenborn, S, Miller, Michael, Tilma, Bauke W, Südmeyer, Thomas, Keller, Ursula

2011, Hoffmann, Martin, Sieber, Oliver D, Wittwer, Valentin, Krestnikov, Igor L, Livshits, Daniil A, Barbarin, Yohan, Südmeyer, Thomas, Keller, Ursula