Université de Neuchâtel

Towards compact ultralow phase noise lasers and microwave signals based on new approaches

Brochard, Pierre ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2019.

Today, the lowest phase noise microwave signals are generated optically by frequency division of an ultra-stable optical reference using a femtosecond frequency comb. In the commonly used approach, the ultra-stable optical reference is obtained by frequency-stabilizing a laser to a high-finesse ultra-low expansion optical cavity, and the frequency division is performed by optically locking a...

Université de Neuchâtel

Compact laser sources from the extreme ultraviolet to the mid-infrared spectral range

Merceron, Loïc P. J. M. ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2019.

Lasers have revolutionized the way we live and work in so many ways and have become a major part of our lives. We use them in telecommunications, medical care, material processing, data storage and printing, just to name a few. Lasers have proved to be important tools and are a major subject of research in science, continuously developed further and finding new uses. Pushed by the need to...

Université de Neuchâtel

Semiconductor disk laser-based frequency combs

Jornod, Nayara ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

This thesis studies the first self-referenced frequency combs based on modelocked semiconductor disk lasers (SDLs). The generation of stabilized frequency combs based on ultrafast lasers has been a significant breakthrough for many applications in various fields of physics, spectroscopy and metrology. Optical frequency combs can serve as a frequency ruler that provides a direct and...

Université de Neuchâtel

Compact ultrafast frequency combs

Hakobyan, Sargis ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

Optical frequency combs provide a direct and phase-coherent link between the optical spectral region of the electromagnetic spectrum (i.e., hundreds of THz frequencies) and the radio-frequency domain (MHz-GHz frequencies). As a result, they constitute a unique and powerful tool for various applications such as broadband high-resolution molecular spectroscopy, optical metrology, astrophysics,...

Université de Neuchâtel

Novel laser sources for metrology and spectroscopy

Gürel, Kutan ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2017.

Lasers have revolutionized the photonics field as a coherent intense light source, capable of performing many tasks. They are widely used in industrial and medical applications, as well as for scientific research. Two important areas of applications are frequency metrology and spectroscopy. Quantum cascade lasers (QCL) cover a wide spectral region in the mid-infrared where most molecules exhibit...

Université de Neuchâtel

Experimental techniques for optical frequency metrology

Bucalović, Nikola ; Thomann, Pierre (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2014.

In the framework of this thesis, I present recent activities in the Laboratoire Temps-Fréquence (LTF) of the University of Neuchâtel, concerning the optical frequency metrology group. We developed the frequency discriminator technique for the characterization of the narrow linewidth heterodyne optical beats. The examination of the four different types of the frequency and phase discriminators...

Université de Neuchâtel

Analysis and improvement of the spectral properties in mid-infrared semiconductor quantum cascade lasers

Tombez, Lionel ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2014.

Quantum Cascade Lasers (QCLs) are semiconductor lasers based on intersubband transitions in semiconductor heterojunctions. Unlike conventional laser diodes, the emission wavelength of QCLs is not defined by the energy gap between the conduction and valance bands of the semiconductor material, but by the energy spacing between the discrete states of quantum wells, which enables the realization of...