25ème Congrès Général de la SFP 2019

Optically controlling the emission chirality of microlasers

Non programmé

2h 30m

Auditorium 450 (Cité des Congrès)

Poster Séance Poster

Orateur

M. Nicola Carlon Zambon (Centre de Nanosciences et de Nanotechnologies (C2N), CNRS – Université Paris-Saclay, Palaiseau, France)

Description

The orbital angular momentum (OAM) of light, emerging in helical light beams, is an unbounded degree of freedom that appears very advantageous for applications ranging from optical manipulation to classical and quantum information multiplexing. Right now, one of the main limitations of integrated lasers generating OAM is their lack of versatility, as they rely on engineering chiral resonators, thus imposing a unique, non-tailorable chirality of the emission, i.e. clockwise or counter-clockwise. Here, we propose and demonstrate, using a fully integrated device, a novel scheme where the chirality of a lasing mode carrying OAM can be optically controlled. To do this, we use a semiconductor planar microcavity embedding a single quantum well (i.e. a VCSEL), where we etch a hexagonal ring of overlapping micropillars. In such resonators exhibiting discrete rotational symmetry, the angular momentum of photons, associated to the phase winding of the optical modes, couples to their spin. As a result, it is possible to trigger lasing in a mode carrying a net OAM by spin-polarizing the gain medium with a circularly polarized optical pump. This allows optically breaking time-reversal symmetry and thus controlling the chirality of the emission solely by changing the polarization of the pump. Importantly, these schemes are very general and can be extended to devices presenting higher values of OAM, thus paving the way to the engineering of novel laser sources with optically tunable OAM.