Fiber-based sources for bio-medical imaging
Non-linear imaging is among the fastest growing research areas today, driven by the advances in laser technology and high-speed electronics. Since these imaging techniques require a widely tunable high intensity radiation, optical parametric oscillators are usually employed. However, these sources make it impractical to utilize these imaging techniques in a clinical environment, e.g. during medical procedures, where additional requirements on the compactness and robustness of the laser source have to be met. Driven by this challenge, we have focused our research on four-wave mixing (FWM) as a flexible wavelength conversion technique that happens directly in optical fibers. Thus, an all-fiber front-end and amplifier system has been developed to fully exploit the advantages of this scheme. This work has resulted in the first small footprint, maintenance-free, all-fiber optical parametric oscillator system able to generate the pulse parameters required for coherent Raman imaging applications. This system features an exceptional noise figure that allow for high-speed SRS imaging with a good signal-to-noise ratio. Finally, this versatile laser concept is capable to generate ultra-short pulses by temporally compressing its output driving three-photon excited fluorescence imaging in spectral regions with low tissue absorption.
The combination of FWM-based conversion, coupled with an all-fiber laser makes this solution practical for applications of CRS microscopy in a clinical environment. This laser concept could very well be the missing key to establish non-linear imaging as a diagnostic tool in bio-medical domains.
Jens Limpert received his M.S in 1999 and Ph.D. in Physics from the Friedrich Schiller University of Jena in 2003. His research interests include high power lasers in the pulsed and continuous-wave regime. Jens Limpert is currently leading the Laser Development Group (including fiber- and waveguide lasers) at the Institute of Applied Physics. He is author or co-author of more than 270 peer-reviewed journal papers in the field of laser physics. His research activities have been awarded with the WLT-Award in 2006, an ERC starting grant in 2009 and an ERC consolidator grant in 2013. Jens Limpert is founder of the Active Fiber Systems GmbH a spin-off from the University Jena and the Fraunhofer-IOF Jena.