Nonlinear spectral broadening based on self-phase modulation followed by pulse compression is a well-established approach in high average power and ultrashort pulse duration systems. One exemplary implementation uses free space propagation through a nonlinear medium (solid or gas) in a multipass arrangement. Scaling this method beyond the 10 mJ-range is mainly limited by three detrimental effects: excessive self-focusing, laser-induced mirror damage and gas ionization. Dominantly multipass cells are realized with a Herriott-cell arrangement comprising two concave mirrors. Here we suggest a different approach, a concave-convex geometry. No foci are present in these multi-pass cells, mitigating the ionization problem. The decreased intensity permits the arrangement's folding, reducing the required footprint for practical applications.
In this work, we propose a new concept of phase-matching based on multiple passes of interacting beams through the same nonlinear crystal placed inside a multi-pass cell. We show that materials such as crystalline quartz, can be quasi-phase-matched in such a multipass arrangement. Moreover, we have demonstrated enhanced conversion efficiency approaching 40% with very low, 10 MW/cm2 intensity in the 2-mm thick KTP crystal inside a multipass arrangement.
Thus we present the first proof-of-concept experimental demonstration of χ(2) multipass nonlinear optics where free space birefringent phase-matching and quasi-phase matching can be realized with nearly all types of nonlinear materials.
In this work we will present a new diode-pumped, OPCPA-based few-cycle, high energy, high power mid-infrared laser system, providing few-cycle pulses at high repetition rate. Plans for its subsequent amplification to the mJ level at 10 Hz are also shown.
These lasers will be used as the main drivers for high harmonic generation and laser-plasma acceleration experiments in Portugal. Additionally, they will be open for access by external users. This will be an unprecedented experimental capability at the national level, allowing experiments in a novel physical regime.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.