Speaker Bio

Erez Hasman is the Schlesinger chaired Professor at the Technion – Israel Institute of Technology, Russell Berrie Nanotechnology Institute & Helen Diller Quantum Center, Haifa, Israel and head of the Atomic-scale Photonics Laboratory. He received the B.Sc. degree in physics in 1981 from Tel Aviv University, the M.Sc. degree in 1985 from the Technion, Haifa, and the Ph.D. in 1992 from Weizmann Institute of Science, Rehovot. Before joining the Technion Erez was a senior project physicist and served as the chief physicist in high-Tech industries. He was also a Visiting Professor at Stanford University, Stanford, CA. (2011-2012).  Lab website: https://hasman.technion.ac.il

Erez initiated and demonstrated the first metasurface, pioneering the field of optical metasurfaces [the first metallic metasurface (2001); dielectric metasurface (2002); orbital angular momentum metasurface (2002); vectorial vortex metasurface (2002); the first meta-lens (2003)]. His research group has made significant contributions in the field of nanophotonics, metasurfaces and radiative heat transfer from nanoscale structures, as well as the first to report on spin-valley Rashba monolayer laser (2023). Among his most significant contributions are the discoveries of the Pancharatnam-Berry phase (geometric phase) metasurfaces utilizing the photonic spin-orbit mechanism, the first to report on the shared-aperture multifunctional metasurfaces, geometrodynamics of spinning light, photonic spin Hall effect, photonic Aharonov–Bohm effect, photonic Rashba effect, and quantum photonic metamaterials (experimental observation of quantum entanglement using metasurfaces).

Erez was awarded the Fellow of OSA in 2013, “for pioneering contributions in the field of nano-photonics, and specifically for developing a new branch in optics – Spinoptics: the symmetry breaking in nanostructures due to spin-orbit interaction”. Spinoptics has opened a new avenue for controlling light in nanometric and atomic-scale optical devices. His publications in prestigious journals such as Science, Nature Photonics, Nature Nanotechnology, Nature Materials, Physical Review Letters have been cited over 14,000 times.

Abstract:

Direct-bandgap transition metal dichalcogenide monolayers are appealing candidates to construct atomic-scale spin-optical light sources owing to their valley-contrasting optical selection rules. Recently, we reported a coherent and controllable spin-optical monolayer laser by incorporating a WS2 monolayer into a heterostructure microcavity supporting high-Q spin-valley resonances, without requiring magnetic fields or cryogenic temperatures.

   Our spin-valley microcavity is constructed by interfacing an inversion-asymmetric (core) and an inversion-symmetric (cladding) planar photonic spin lattice for laterally confined spin-valley states. Inspired by valley pseudospins in monolayers, the high-Q spin-valley states are created via the photonic Rashba-type spin splitting of a bound state in the continuum, which remains highly confined in space due to symmetry mismatch between its near field and outgoing propagation field. A WS2 monolayer is used as the gain material for its strong exciton binding energies and unique valley pseudospins. Specifically, ±K' valley excitons can be selectively excited using spin-polarized pump light, thus enabling active control of the sources without magnetic fields.

   The photonic spin-valley Rashba effect provides a general mechanism for constructing surface-emitting spin-optical light sources. We envision the monolayer-integrated spin-valley microcavities as a multidimensional platform to study coherent spin-dependent phenomena in both classical and quantum regimes by exploiting electron and photon spins.

References:

Nature Materials 22, 1085-1093 (2023).

Nature Nanotechnology 15, 927-933 (2020).