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Vorrichtung zum Verstaerken von Lichtimpulsen

Light pulse amplifier generating high energy laser pulses employs self-phase modulation of pulses and additional element for compensation of dispersion
 
: Schimpf, D.; Limpert, J.; Tünnermann, A.

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Frontpage ()

DE 102008047226 A: 20080912
DE 102008047226 A: 20080912
H01S0003
German
Patent, Electronic Publication
Fraunhofer IOF ()

Abstract
(A1) Die vorliegende Erfindung betrifft eine Vorrichtung (1, 11) zum Verstaerken von Lichtimpulsen (2, 12), mit einem Strecker (4, 14), der die Lichtimpulse (2, 12) zeitlich streckt, wenigstens einem Verstaerker (5, 15), der die gestreckten Lichtimpulse (2, 12) verstaerkt, und einem Kompressor (6, 16), der die gestreckten und verstaerkten Lichtimpulse (2, 12) rekomprimiert, wobei der Strecker (4, 14) und der Kompressor (6, 16) dispersive Elemente mit im Wesentlichen entgegengesetzt gleicher Dispersion sind. Um eine Vorrichtung (1, 11) zum Verstaerken von Lichtimpulsen (2, 12) bereitzustellen, welche kompakt aufgebaut und flexibel einsetzbar ist, wird mit der Erfindung vorgeschlagen, dass die Dispersion des Verstaerkers (5, 15), die Dispersion weiterer optischer Elemente der Vorrichtung (1) und/oder die Fehlanpassung der Dispersion von Strecker (4, 14) und Kompressor (6, 16) durch Selbstphasenmodulation der Lichtimpulse (2, 12) und/oder durch wenigstens ein zusaetzliches Element (17) variabler Dispersion zumindest teilweise kompensiert sind.

 

WO 2010028837 A1 UPAB: 20100331 NOVELTY - The light pulse amplifier (1) includes a stretcher (4) which extends the light pulses (2) over time, an amplifier (5) and a compressor (6) which recompresses the pulses. The stretcher and compressor are both dispersive elements with dispersions of the same magnitude but opposite in sign. Dispersion of the amplifier, of further optical elements of the amplifier, and/or defective matching of the amplifier and compressor are at least partially compensated. This is achieved by self phase modulation (SPM) of the pulses and/or by use of an additional element of variable dispersion. DETAILED DESCRIPTION - Dispersive elements of the stretcher and/or compressor have dispersion which is static or which can be varied in steps. Dispersion of the additional element is continuously-variable. The dispersive elements of the stretcher and/or compressor are refraction gratings, chirped fiber optics or volume-optical Bragg gratings, prisms or waveguide structures such as optical fibers. The additional element is an adjustable prism or refraction grating pair or an acousto-optical element or a liquid crystal element. Dispersion of the additional element is smaller in magnitude than the dispersion of the stretcher or compressor. The shape of the light pulse is parabolic, sech2 or Gaussian. At least one further variable-dispersion element is placed ahead of the stretcher or between the stretcher and the amplifier. Energy and duration and amplification of the pulses are matched such that the individual dispersions cited, are compensated completely through self phase modulation. An INDEPENDENT CLAIM is included for the corresponding method of light pulse amplification. USE - A light pulse amplifier generating high energy laser pulses. ADVANTAGE - Picosecond or femtosecond pulses are amplified. Power levels in the petawatt range are reached. Stretching and recompression avoid damage to optical elements and reduce non-linear effects. The method is also known as chirp-modulated pulse amplification (CPA). In the new arrangement, the overall compensation of dispersion is improved. The effects of non-ideal recompression and non-linearity are compensated. The new amplifier can be used in various applications without replacement of elements. Quasi-continuous control of compensation is achieved. The amplifier is versatile and compact in its construction. Choice of pulses with parabolic shape allows exact compensation of second order dispersion; good results are also achieved with other pulse shapes.

: http://publica.fraunhofer.de/documents/N-139631.html