Ultrafast Optics - Tampere University of Technology

Ultrafast Optics Group

The Ultrafast Optics Group focuses on the study of nonlinear phenomena and dynamics associated in waveguide structures. The research conducted involves theoretical studies, the development of advanced computational models as well as experimental investigations. Current interests extreme energy localization in chaotic and turbulent regimes and the stimulation of waves with extreme amplitudes in optical fibers. The group also develops broadband optical sources with characteristics tailored to specific applications such as spectroscopy or coherent optical tomography.

Extreme events in optical systems

Noise on ultra-short laser pulses injected into a highly nonlinear optical fiber behaves like an “optical wind” and can lead to a small number of pulses with extremely large amplitude and energy. Such optical “rogue” or “freak” waves in optical fibers have opened up the possibility to use optical systems for studying extreme-value processes. Our group focuses on the dynamics of the extreme waves, how they can appear spontaneously in a chaotic and turbulent environement, what factor can favour they occurence and how can they can stimulated in a systematic way. Recent results include the establishment of a connection bteween extreme events and soliton/breathers collisions, the first direct observation of the peregrine soliton in a continuous system, the systematic stimulation of freak waves by stimulated modulation instability.

Broadband sources for spectroscopy and OCT

Current supercontinuum sources are typically based on photonic crystal fibers or highly nonlinear fibers made of silica glass. However, the high losses of silica in the ultraviolet and mid-infrared ranges typically limit the bandwidth of the supercontinuum to visible and near-infrared wavelengths. We are developping supercontinuum cources in the ultraviolet and mid-infrared sources for spectroscopy and OCT.

 

Second-order coherence of supercontinuum

For many applications the knowledge of supercontinuum coherenceproperties is essential as it can have a significant impact on the performance. For example, high coherence is paramount for frequency metrology, telecommunication, or coherent spectroscopy, while white-light interferometry and optical coherence tomography typically require a large bandwidth. We analyze the coherence properties of supercontinuum using two-frequency cross-spectral density and two-time mutual coherence functions that are traditionally employed in second-order coherence theory of non-stationary light .

 

The list of publications can be found in TUTCRIS database

Updated by: Robert Czaplicki, 10.02.2017 19:03.
Keywords: science and research, laboratory of photonics, ultrafast optics