Beam shaping: from light optics to electron wavefunctions

Friday, October 16, 2015 -
3:00pm to 4:00pm
Roy Shiloh
Speaker's Institution: 
Tel-Aviv University

 In light optics, beam shaping is done in a multitude of techniques and approaches: whether it be using refractive or diffractive elements, whether the underlying is based on plasmonics, linear optics, photonic crystals - the possibilities seem endless. In the exciting field of nonlinear optics, for example, one could make use of a ferroelectric crystal to transfer energy from an impinging laser light to its spectral harmonics. The crystal is traditionally engineered to generate a new frequency, however, it may also be made to spatially fashion the generated beam as desired [1], or, using the versatility of nonlinear interactions, shape the spectrum of the beams [2-3]. Owing to the similarity between the dynamics of light- and electron-waves, the concept of holography, which was first invented as a solution to the aberrations in electron microscopes, was soon borrowed and considerably developed in light-optics. Consequently, the extremely useful idea of computer-generated holography emerged: here, the physics are first simulated using a computer, and accordingly a holographic plate is fabricated. In recent years, the advances in fabrication technology enabled complex electron beam shaping to become a reality, which is currently the focus of my research: among others, we have experimentally demonstrated shaping of the electron wavefunction using nanoscale computer-generated holographic masks [4], and investigated the acceleration and OAM of electron beams [5]. From nearly-arbitrary wavefronts to the correction of optical aberrations [6], these ideas may shape the future of electron-optics.