ATTOSECOND OPTICS

Harnessing attosecond nonlinear optics for controlling and enhancing high harmonic generation and producing useful coherent x-rays on a tabletop

 Partecipanti

Mappa

 Word cloud

Esplora la "nuvola delle parole (Word Cloud) per avere un'idea di massima del progetto.

 Obiettivo del progetto (Objective)

'Attosecond nonlinear optics will be harnessed for increasing the efficiency and tunability of laser-driven x-rays through high harmonics generation. The process of high harmonic generation, which converts visible laser light into laser-like x-rays, facilitates new directions in science and technology. Examples include the production of attosecond pulses of light that allows direct investigation of the motions of electrons in atoms, molecules, and materials as well as the compact generation of x-rays for nano and bio imaging. However, for most applications, the generation of usable flux is, to date, limited to relatively long wavelengths (>10 nm) in which the upconversion process is rather benign and can be fully phase matched. At the foundation of this proposal are all-optical quasi-phase matching techniques, recently pioneered by the author during his post-doc in USA, which allows the holographic creation of nonlinear structures in the high harmonic generation process. Similarly to photonic structures for visible light, the optically induced nonlinear structures can be used for manipulating and enhancing the generated x-rays. New quasi-phase matching techniques will be developed and implemented for generating harmonics at 10-1 nm with high flux. Periodic structure with periodicity that varies according to the phase matching conditions of a given harmonic order will be used for generating coherent quasi-monochromatic x-rays while stochastic structures will be exploited for generating wideband x-rays. Longitudinally chirped periodic structures will be used for generating sub 100 attosecond pulses while transversely parabolic periodic structures will be exploited for focusing the generated beam at a required distance from the nonlinear medium. The proposed research will have important impact on the generation of compact and bright coherent x-rays for applications in materials and chemical dynamics, nanotechnology, microscopy, biology, and medicine.'

Descrizione progetto (Article)

Attosecond optical pulse generation is revolutionising physics and chemistry in laboratories around the world.

It enables probe spectroscopy to view molecular motion and electron transfer between atoms.

High harmonic generation is a common way to convert a laser source of lower frequency into higher frequencies to achieve very fast pulses.

The technology is a highly non-linear optical process with exciting potential for molecular imaging and compact generation of X-rays for bio- and nano-imaging.

However, conversion efficiency relating the produced intensity to the input intensity is relatively low, largely due to de-phasing or poor phase matching of the non-linear conversion process.EU-funded scientists enhanced the conversion efficiency of high harmonic generation through two different approaches to quasi-phase matching within the scope of the project ATTOSECOND OPTICS.

Sharp sawtooth grating-assisted phase matching exhibited conversion equivalent to conventional phase matching and closely approaching the ideal case.

Secondly, the team also developed ways to control the spectral, temporal and spatial characteristics of the attosecond pulses and the polarisation properties of the produced beam.

Scientists are currently developing a novel device based on the high harmonic generation technology.The ability to produce attosecond pulses of high intensity by increasing conversion efficiency has been long sought.

ATTOSECOND OPTICS has achieved this, paving the way to high-performance table-top X-rays and other imaging and analysis devices.