F. Krausz

Ultrabroadband ring oscillator for sub-10-fs pulse generation

A four-mirror ring cavity formed by chirped dielectric mirrors is proposed for self-mode-locked solid-state lasers. It offers, for the first time to our knowledge, the potential for approaching the gain-bandwidth limit in Ti:sapphire and related broadband lasers. Using this concept, we produced nearly bandwidth-limited 7.5-fs pulses from a feedback-initiated, self-mode-locked Ti:sapphire ring oscillator. Our experiments provide new insight into the physics and limitations of sub-10-fs oscillators.

Femtosecond passive mode locking of a solid‐state laser by a dispersively balanced nonlinear interferometer

A Michelson interferometer containing a nonlinear fiber in one arm and dispersion control in the other arm has been used for passive mode locking of a continuous wave Nd:glass laser. We discuss scaling issues and demonstrate the usefulness of this technique by generating ≊300 fs pulses with only Pf≊15 mW of average power in the fiber and ≊100 fs pulses with a self‐starting threshold of Pf≊100 mW.

Chirped dielectric mirrors for dispersion control in femtosecond laser systems

Optical thin film structures exhibiting high reflectivity and nearly constant negative group- delay dispersions, or optionally superimposed higher-order dispersions over frequency ranges beyond 80 THz are presented. This attractive combination makes these special laser mirrors well suited for intra- or extracavity dispersion control in broadband femtosecond laser systems. We address design issues and the principle of operation of these novel devices. Spectrally resolved white-light interferometry with high time and spectral resolution was used to measure the dispersion of the deposited mirrors. Experimental results on the operation of femtosecond laser systems utilizing dispersion compensating mirrors are given.

Pump-Seed Synchronization Measurements for High-Power Short-Pulse Pumped Few-Cycle OPCPA System

We present the development of an optically synchronized frontend of a high-power short-pulse pumped few-cycle OPCPA system and single shot pump-seed timing jitter measurements at the position of its first OPCPA stage.

Controlling the absolute phase of few-cycle light pulses

Using a coherent nonlinear optical technique, measurement of the temporal evolution of the absolute phase of 6-fs light wave packets has been demonstrated, permitting the generation of intense, few-cycle light with precisely-known electric and magnetic fields.

Femtosecond High Repetition Rate External Cavity beyond the Average Power Limit for Linear Enhancement

We report on the cavity enhancement of a 78MHz, 200fs ytterbium-fiber laser system. Linear enhancement up to a record intra-cavity power of 18kW has been observed. In a non-linear enhancement regime 40kW have been reached.

Compression of mJ-Scale Chirped-Amplified Pulses to sub-20 fs Using High-Dispersive Mirrors

We presented the development of an all-dispersive-mirror compressor for sub-TW CPA systems. The compression of 4.8-ps 1.4-mJ amplified stretched pulses to 19.1 fs is demonstrated, using 52 reflections on high-dispersive mirrors with ~90% throughput.

High-Energy, Diode-Pumped Laser Amplification in Yb:CaF 2 and Yb:SrF 2

We present nanosecond pulse amplification to the Joule-level based on diode-pumped Yb:CaF2and Yb:SrF2. When seeding with microsecond pulses a maximum pulse energy of 1.54 J at a repetition rate of 1 Hz was achieved.

Coherent kiloelectronvolt X-ray emission from laser-driven atoms

J. Seres1, E. Seres1,2, Ch. Streli3, P. Wobrauschek3, Ch. Spielmann2, F. Krausz1,4,5 1Institut für Photonik, Technische Universität Wien, Austria; 2 Physikalisches Institut EP1, Universität Würzburg, Germany; 3Atominstitut der Österreichischen Universtitäten, Technische Universität Wien, Austria; 4Max-Planck-Institut für Quantenoptik, Germany; 5Department für Physik, Ludwig-Maximilians-Universität München, Germany jozsef.seres@tuwien.ac.at,

Monolithic device for carrier-envelope phase stabilization

A new scheme for stabilizing the carrier-envelope phase (CEP) of a few-cycle laser pulse train is demonstrated. Self-phase modulation and difference-frequency generation in a single periodically-poled crystal allows CEP locking directly in the usable output.