Book/Report/Dissertation / PhD Thesis

PUBDB-2017-00199

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Advanced ultrafast fiber laser sources enabled by fiber nonlinearities

Liu, W. (Corresponding author)CFEL*DESY*

2017
Verlag Deutsches Elektronen-Synchrotron Hamburg

This record in other databases:

Please use a persistent id in citations: doi:10.3204/PUBDB-2017-00199

Report No.: DESY-THESIS-2017-020

Abstract: Development of high power/energy ultrafast fiber lasers for scientific research and industrial applications is one of the most exciting fields in ultrafast optics. This thesis demonstrated newmeans to improve two essential properties—which are indispensable for novel applications such as high-harmonic generation (HHG) and multiphoton microscopy (MPM)—of anultrafast fiber laser system: energy scaling capability and wavelength tunability. High photon-flux extreme ultraviolet sources enabled by HHG desire high power (>100 W), high repetition-rate (>1 MHz) ultrafast driving laser sources. We have constructed from scratch a high-power Yb-fiber laser system using the well-known chirped-pulse amplification (CPA) technique. Such a CPA system capable of producing ∼200-W average power consists of a monolithic Yb-fiber oscillator, an all-fiber stretcher, a pre-amplifier chain, a main amplifier constructed from rode-type large pitch fiber, and a diffraction-grating based compressor. To increase the HHG efficiency, ultrafast pulses with duration <60 fs are highly desired. We proposed and demonstrated a novel amplification technique, named as pre-chirp managed amplification (PCMA). We successfully constructed an Yb-fiber based PCMA system that outputs 75-MHz spectrally broadened pulses with >130-W average power. The amplified pulses are compressed to 60-fs pulses with 100-W average power, constituting a suitable HHG driving source. MPM is a powerful biomedical imaging tool, featuring larger penetration depth while providing the capability of optical sectioning. Although femtosecond solid-state lasers have been widely accepted as the standard option as MPM driving sources, fiber-based sources have received growing research efforts due to their superior performance. In the second part of this thesis, we both theoretically and experimentally demonstrated a new method of producing wavelength widely tunable femtosecond pulses for driving MPM. We employed self-phase modulation to broaden a narrowband spectrum followed by bandpass filters to select the rightmost/leftmost spectral lobes. Widely tunable in 820-1225 nm, the resulting sources generated nearly transform-limited, ∼100 fs pulses. Using short fibers with large mode-field-diameter for spectral broadening, we obtained ultrashort pulses with the pulse energies up to 20 nJ. We applied such an enabling source to drive MPM imaging of both cancer cells and skin samples.

Note: Universität Hamburg, Diss., 2016

---

Contributing Institute(s):

1. FS-CFEL-2 (CFEL-UFOX)
2. Ultrafast Lasers & X-rays Division (FS-CFEL-2)
3. FS-CFEL-2 (CFEL-ULOCM)

Research Program(s):

1. 6211 - Extreme States of Matter: From Cold Ions to Hot Plasmas (POF3-621) (POF3-621)
2. VH-NG-804 - Towards Laboratory-Based Ultrafast Bright EUV and X-ray Sources (2015_IVF-VH-NG-804) (2015_IVF-VH-NG-804)

Experiment(s):

1. Experiments at CFEL

Appears in the scientific report 2016

---

Database coverage:

---