High power ultrafast lasers

In this article, we review progress in the development of high peak-power ultrafast lasers, and discuss in detail the design issues which determine the performance of these systems. Presently, lasers capable of generating terawatt peak powers with unprecedented short pulse duration can now be built on a single optical table in a small-scale laboratory, while large-scale lasers can generate peak power of over a petawatt. This progress is made possible by the use of the chirped-pulse amplification technique, combined with the use of broad-bandwidth laser materials such as Ti:sapphire, and the development of techniques for generating and propagating very short (10–30 fs) duration light pulses. We also briefly summarize some of the new scientific advances made possible by this technology, such as the generation of coherent femtosecond x-ray pulses, and the generation of MeV-energy electron beams and high-energy ions. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70759/2/RSINAK-69-3-1207-1.pd

Phase-matched optical parametric conversion of ultrashort pulses in a hollow waveguide

We demonstrate for the first time nonresonant phase-matched frequency conversion of ultrashort pulses in gases. Broad-bandwidth ultrafast pulses, tunable around 270 nm, were generated from a Ti:sapphire amplifier system using 2ω+2ω−ω2ω+2ω−ω parametric wave mixing in a capillary waveguide. Both the fundamental and the second-harmonic light were coupled into the lowest-order (EH11)(EH11) mode. The output pulses have an energy >4μJ at a 1kHz repetition rate, in the EH11EH11 spatial mode. This method can be made to generate 10–20fs pulses, and is the first phase-matching technique which is applicable to frequency conversion into the deep- and vacuum-ultraviolet regions of the spectrum. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87447/2/331_1.pd

Learning from learning algorithms: application to attosecond dynamics of high-harmonic generation

Includes bibliographical references (pages 043404-5).Using experiment and modeling, we show that the data set generated when a learning algorithm is used to optimize a quantum system can help to uncover the physics behind the process being optimized. In particular, by optimizing the process of high-harmonic generation using shaped light pulses, we generate a large data set and analyze its statistical behavior. This behavior is then compared with theoretical predictions, verifying our understanding of the attosecond dynamics of high-harmonic generation and uncovering an anomalous region of parameter space

Coherent x-ray generation at 2.7nm using 25fs laser pulses

We demonstrate for the first time that coherent soft-x-ray pulses at wavelengths of 2.7nm can be generated using 25fs driving pulses. High-order harmonic generation in He is used to produce the femtosecond x-ray harmonics, which exhibit discrete individual orders up to 221, followed by a continuum of unresolved harmonics which extend up to at least the 299th order, corresponding to a wavelength of 2.7nm, or an energy of 450eV. The large ionization potential of He, together with the ultrashort nature of the driving field, results in this dramatic extension of the harmonic plateau, by approximately 200 orders more than has been observed previously. We also obtain excellent agreement with theoretical predictions. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87449/2/296_1.pd

High-efficiency, single-stage 7-kHz high-average-power ultrafast laser system

Includes bibliographical references (page 467).We demonstrate a simple and practical single-stage ultrafast laser amplifier system that operates at a repetition frequency from 1 to 10 kHz, with millijoule pulse energy and as much as 13 W of average power. The repetition rate can be adjusted continuously from 1 to 10 kHz by new all-solid-state pump laser technology. This is to our knowledge the highest average power ever obtained from a single-stage ultrafast laser amplifier system. This laser will significantly increase the average power and the repetition rate that is easily accessible for high-field experiments such as coherent x-ray generation or for laser-synchrotron studies

Phase-Coherent Optical Pulse Synthesis from Separate Femtosecond Lasers

We generated a coherently synthesized optical pulse from two independent mode-locked femtosecond lasers, providing a route to extend the coherent bandwidth available for ultrafast science. The two separate lasers (one centered at 760 nanometers wavelength, the other at 810 nanometers) are tightly synchronized and phase-locked. Coherence between the two lasers is demonstrated via spectral interferometry and second-order field cross-correlation. Measurements reveal a coherently synthesized pulse that has a temporally narrower second-order autocorrelation width and that exhibits a larger amplitude than the individual laser outputs. This work represents a new and flexible approach to the synthesis of coherent light