Spinning Light

The spin Hall effect – the impact of the intrinsic spin on the particle trajectory, which produces transverse deflection of the particle – is a central tenet in the field of spintronics regarding particles of electrons. Now, its optical equivalent has been observed.

The Magnus effect is seen in a wide range of systems. For example, it describes the sideways force applied to a spinning ball as it travels through the air explains Prof. Erez Hasman, head of the Micro- and Nanooptics Laboratory and an avid tennis player.

Light waves, comprising mass-less particles called photons, also demonstrate spin. Light’s spin is determined by its polarization: whether the wave vibration rotates in one direction or the opposite as it travels. Hasman, together with his PhD student Avi Niv, Dr Vladimir Kleiner – a senior scientist in the lab – and Ukrainian visiting scientist Dr Konstantin Bliokh, were the first to observe the effect of spin on the trajectories of polarized light beams.

Prof. Erez Hasman in the Micro- and Nanooptics Laboratory

Prof. Erez Hasman

The researchers launched a laser beam at a sliding angle to the internal surface of a glass cylinder. Once inside the cylinder the beam traveled in a helical trajectory along the glass-air interface, and was collected and analyzed at the far end using polarization optics and a camera. They observed a transverse spin-dependent deflection of the optical beam. These results have promising applications in nano-optics leading to much faster and more accurate computational data processing.

Physics Prof. Mordechai (Moti) Segev, a world leader in the area of Nonlinear Optics, comments, “Nanophotonics is a field where light is manipulated and controlled on a scale that is smaller than the optical wavelength. Erez Hasman has written a series of important papers in this area, leading to a new branch in optics – spinoptics. His discoveries offer an unprecedented ability to control light and its polarization state in nanometer-scale optical devices, thereby facilitating a variety of applications related to nanophotonics.”

Applied to other areas Hasman says, “There are a number of systems where the spin of a particle couples with its trajectory in high-energy and condensed matter physics. The math is the same in all cases, but experimentally it’s hard to understand what’s going on. Our experimental system offers a new way to get at some of these fundamental questions clearly and precisely.”

For this research, Hasman received the Henry Taub Prize for Academic Excellence in June 2009.

What is Photonics?

Photonics is the science of generating, controlling, and detecting photons. Photonics researchers investigate the emission, transmission, amplification, detection, and modulation of light. Applications include laser manufacturing, biological and chemical sensing, medical diagnostics and therapy, display technology, and optical computing.

Spinoptics: The Magnus effect for light, also called the optical spin Hall effect, causes the light to deflect due to the interaction between the intrinsic spin of the photons and the shape of the light’s trajectory.