Theoretical and experimental studies of broadband phase-controlled attosecond mirrors

Abstract

We present procedures to develop and characterise chirped multilayer mirrors for attosecond pulses. The design procedure involves a simulated annealing optimisation algorithm to obtain a multilayer structure with the desired performances. The characterisation step requires the use of well-calibrated attosecond and synchrotron beam lines, allowing one to measure the amplitude and phase response of the mirror. We illustrate these approaches with a set of mirrors designed to have zero or negative dispersion. The remarkable agreement between theoretical and experimental performances validates this overall process, and demonstrates the capability of such mirrors to control the temporal profile of attosecond pulses. These tools and techniques for developing attosecond chirped mirrors will facilitate the generalisation of such components on attosecond experiments.

Reflective Spiral Phase Converter: A New Route to Ultrafast Singular Optics

“…Fine tuning of the mirror properties to further reduce oscillations in the dispersion properties can be achieved with computer optimization. Computer optimized mirrors have been used for generation of up to attosecond pulses [38].…”

“…Results presented in this work are customs design for a given wavelength range and dispersion profile. Computer optimized chirped mirrors have been used for generation of up to attosecond pulses [38]. Thus, chirped mirrors provide solution to the problems discussed including compensation of higher-order dispersion.…”

Design optimization of broadband extreme ultraviolet polarizer in high-dimensional objective space

“…Our researches demonstrate the capability of our method in designing EUV broadband polarizer, and it has a potential to extend to design other optical multilayers, such as EUV broadband mirror, [11,12] EUV beamsplitter, [13] and chirped mirrors. [14,17]…”

“…Meanwhile, it is worth pointing out that multi-objective optimization is a quite common requirement in the designs of EUV multilayers, such as EUV broadband mirror, [11,12] EUV beam splitter, [13] and EUV chirped mirror. [14] Therefore, the multi-objective optimization is a fundamental issue to be addressed for the development of EUV optics.…”

Broadband multilayer optics for ultrafast EUV absorption spectroscopy with free electron laser radiation

“…In the EUV spectral range multilayer (ML) mirror technology usually represents a valid solution, as it allows for near-normal incidence geometries and tight focusing of the beam. Such MLs are fundamental in a very wide range of applications: in atto-physics, where they allow the manipulation of high order harmonics by compressing ultra-fast pulses in the atto-second regime [2,3]; in space experiments, where they are employed in astrophysical instrumentation dedicated to observations useful in space weather studies solar disk and coronal plasma [4]; in the microelectronics industry, where they are used as coatings for mirrors and projection masks in the extreme ultraviolet lithographic apparatus for integrated circuit production [5]. However, MLs may also be quite sensitive to effects induced by aging, environment and intense irradiations and these issues are still under investigation in the EUV community.…”