Alessio Bosco

Femtosecond pulses chirping compensation by using one-dimensional compact multiple-defect photonic crystals

Transmission properties of ultrashort pulses propagating through one-dimensional photonic crystals with multiple defects (cavities) were experimentally investigated. Coupling between multiple cavities is responsible for a wide resonance inside the photonic crystal gap suitable to distortion free propagation of 70fs pulses at 800nm. Geometry-induced anomalous dispersion across the resonance allows a compensation of 15% chirp preinduced on Fourier transform limited 70fs pulses.

ATF extraction line laser-wire system

The ATF extraction line laser-wire (LW) aims to achieve a micron-scale laser spot size and to verify that micron- scale beam profile measurements can be performed at the International linear collider beam delivery system. Recent upgrades to the LW system are presented together with recent results including the first use of the LW as a beam diagnostic tool.

A large aperture electro-optic deflector

An electro-optic laser beam deflector with a clear optical aperture of 8.6 mm has been designed, realized, and tested. The electro-optic material used to implement the device was a MgO:LiNbO3 crystal. The exceptionally large aperture makes the device suitable for applications where fast scanning of high power laser beams is needed. The measured deflection angle was 120 μrad/kV for a total length of electro-optic material of 90 mm. A mode quality analysis of the laser beam revealed that the M2 of the laser is affected by less than 4% during scan operation when maximum driving voltage is applied.

Demonstration of a laserwire emittance scanner for hydrogen ion beams at CERN

A non-invasive, compact laserwire system has been developed to measure the transverse emittance of an H- beam and has been demonstrated at the new LINAC4 injector for the LHC at CERN. Light from a low power, pulsed laser source is conveyed via fibre to collide with the H- beam, a fraction of which is neutralized and then intercepted by a downstream diamond detector. Scanning the focused laser across the H- beam and measuring the distribution of the photo-neutralized particles enables the transverse emittance to be reconstructed. The vertical phase-space distribution of a 3 MeV beam during LINAC4 commissioning has been measured by the laserwire and verified with a conventional slit and grid method.