Optical Stern-Gerlach Effect in Periodically Poled Electro-Optical Crystals

The Stern-Gerlach (SG) effect provided the first direct experimental evidence of the quantization of electron spin. Although some analog SG effects have been proposed in optical systems, finding a perfect optical analog for the SG effect remains a challenge. Here, a novel optical SG effect is demonstrated in periodically poled electro-optical crystals. Induced by an applied electric field, the principal axes of crystal rock periodically along the propagation direction of light. When the quasi-phase-matching condition is satisfied, the electro-optical coupling process within the periodically poled crystal can be accurately described by the Schrodinger-Pauli equation for spin-1/2 particles. The output photons can be deflected toward opposite directions according to their intrinsic spin angular momentum (circular polarizations), since the transversely varying duty cycle of crystal arises an effective magnetic-field gradient. Moreover, the output photons can be separated according to two arbitrary orthogonal polarization states, allowing us to construct high-speed electro-optically tunable polarization beam splitters for arbitrary orthogonal polarization states. Therefore, the optical SG effect provides not only a perfect optical analog for the quantum SG effect but also a useful optical element for optics and quantum physics. A novel optical Stern-Gerlach effect is demonstrated in periodically poled electro-optical crystals, whose principal axes rock periodically when an electric field is applied. The electro-optical coupling process within the crystal can be accurately described by the Schrodinge-Pauli equation for spin-1/2 particles. The output photons can be deflected toward opposite directions according to their intrinsic spin angular momentum. image