TY - GEN

T1 - Microfocusing beamline for XUV-XUV pump-probe experiments using HH generation

AU - Frassetto, Fabio

AU - Anumula, Sunilkumar

AU - Calegari, Francesca

AU - Trabattoni, Andrea

AU - Nisoli, Mauro

AU - Poletto, Luca

PY - 2014/9/5

Y1 - 2014/9/5

N2 - The possibility to obtain micrometric focal spot in the extreme-ultraviolet (XUV) region opens the way to XUV-XUV experiments in high-order harmonics beamlines. A beamline designed for this purpose is here presented. The peculiarity of the optical design relies on the use of only toroidal mirrors in place of the more expensive Cartesian optics. The coma aberration, usually dominating the quality of the focal spot when toroidal mirrors are used with high levels of demagnification, is compensated using mirrors in a subtractive (Z-shape) configuration. In addition, the compensating output mirror decouples the length of the exit arm from the de-magnification factor, in this way the length of the exit arm can be increased to install even a large experimental chamber. Three mirrors with optical power are required, in order to assure an optimal focalization. In order to guarantee a day-to-day reproducible working condition, the mirrors are mounted on remotely adjustable optical stages, that are controlled via a genetic algorithm with the feedback on the quality of the focal spot. This solution helps the users to reach the best focalization conditions in a reliable way. The results obtained during the beamline commissioning phase are presented. Emphasis is placed in the characterization of the spot size and in the performances of the genetic algorithm.

AB - The possibility to obtain micrometric focal spot in the extreme-ultraviolet (XUV) region opens the way to XUV-XUV experiments in high-order harmonics beamlines. A beamline designed for this purpose is here presented. The peculiarity of the optical design relies on the use of only toroidal mirrors in place of the more expensive Cartesian optics. The coma aberration, usually dominating the quality of the focal spot when toroidal mirrors are used with high levels of demagnification, is compensated using mirrors in a subtractive (Z-shape) configuration. In addition, the compensating output mirror decouples the length of the exit arm from the de-magnification factor, in this way the length of the exit arm can be increased to install even a large experimental chamber. Three mirrors with optical power are required, in order to assure an optimal focalization. In order to guarantee a day-to-day reproducible working condition, the mirrors are mounted on remotely adjustable optical stages, that are controlled via a genetic algorithm with the feedback on the quality of the focal spot. This solution helps the users to reach the best focalization conditions in a reliable way. The results obtained during the beamline commissioning phase are presented. Emphasis is placed in the characterization of the spot size and in the performances of the genetic algorithm.

KW - Attosecond

KW - Genetic algorithm

KW - Microfocusing

KW - Pump-probe

KW - Toroidal mirrors

KW - XUV

UR - http://www.scopus.com/inward/record.url?scp=84923006302&partnerID=8YFLogxK

U2 - 10.1117/12.2061867

DO - 10.1117/12.2061867

M3 - Conference contribution

AN - SCOPUS:84923006302

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Adaptive X-Ray Optics III

A2 - O'Dell, Stephen L.

A2 - Khounsary, Ali M.

PB - SPIE

T2 - Adaptive X-Ray Optics III

Y2 - 17 August 2014 through 21 August 2014

ER -