There are two different proposals for the momentum of light in a transparent dielectric of refractive index n: Minkowski's version nE=c and Abraham's version E=

We show in this paper that the quantized energies of light in vacuum can be derived directly from the classical electromagnetic theory through the consideration of statistics based on classical physics, which are just a series of expectation values corresponding to relatively stable statistic distributions of electromagnetic harmonic oscillators. Therefore, the quantization of energy is an intrinsic property of light as a classical electromagnetic wave and has no need of being related to particles. The theory developed in this paper is also used to derive the energy equipartition theorem and the discrete levels of hydrogen atom from classical mechanics.

We have created a one-(rather than two-) dimensional quasi-steady-state photorefractive spatial soliton induced by a laser beam instead of an applied electric field. The formation of this type of spatial soliton depends on the intensity of the self-trapped beam, which is different from quasi-steady-state spatial solitons reported in the literature. The optically induced spatial soliton can be exploited in all optical switching applications.

A new wave coupling theory of linear electrooptic effect has been developed starting from Maxwell's equations and considering the second-order nonlinearity. We give a general solution for the resultant equations. The solution is useful in describing linear electrooptic effect for a light wave propagating along an arbitrary direction with an external dc electric field along any direction in any crystal. Applications to the design of some electrooptic devices are de-scribed.

We have observed two-dimensional bright photovoltaic photorefractive spatial soliton for the first time in a Cu:KNSBN K0.25Na0.75Sr1.5Ba0.5Nb5O15 crystal. Characteristics of the observed spatial soliton are explained by an equivalent electric field induced by the background irradiance.

Radially polarized, circularly symmetric optical vortex solitons are shown to be able to exist in Kerr media beyond paraxial approximation. Unlike those of the paraxial linearly polarized counterparts, the topological charges of these solitons should not be less than 2. The properties associated with these solitons, such as their spatial width, and longitudinal and transverse field profiles, are characterized to depend on their normalized asymptotic intensity 2∞ u and nonparaxial degree. It is found that the asymptotic intensity 2∞ u of these solitons cannot exceed a threshold value in correspondence of which their width reaches a minimum value.

We propose an orbital angular momentum (OAM) generator consisting of two conjugated electro-optic spiral phase plates with two longitudinal electrodes, which enables us to realize the electrically tunable generation of integer or noninteger optical vortices according to the input photon's polarization. We demonstrate that such an OAM generator allows the electro-optic management of the multidimensional OAM vector states, and it would have potential applications in quantum information processing system.

We demonstrate that the conversion of spin-to-orbital angular momentum in a focused vectorial light beam can be forbidden or enhanced by the electric-field-erased or increased spatial anisotropy of a uniaxial crystal undergoing the Pockels effect. A focused right-handed circularly polarized quasi-Gaussian beam incident on an electro-optic crystal strontium barium niobate is taken to illustrate the effect, and a conversion-forbidden electric field E0=−16.87 kV/cm is found. Of special interest is that single photons generated in this effect exhibit an entanglement of 2 deg of freedom of spin and orbital angular momentum, and it is electrooptically controllable.

We demonstrate that single photons from a rotating q-plate exhibit an entanglement in three degrees of freedom of spin, orbital angular momentum, and the rotational Doppler shift (RDS) due to the nonconservation of total spin and orbital angular momenta. We find that the rotational Doppler shift Δω=Ω(Δs + Δl), where s, l and Ω are quantum numbers of spin, orbital angular momentum, and rotating velocity of the qplate, respectively. Of interest is that the rotational Doppler shift directly reflects the rotational symmetry of q-plates and can be also expressed as Δω=Ωn, where n=2(q −1) denotes the fold number of rotational symmetry. Besides, based on this single-photon spin-orbit-RDS entanglement, we propose an experimental scheme to sort photons of different frequency shifts according to individual orbital angular momentum.

We propose an arbitrary-to-linear or linear-to-arbitrary polarization controller based on the mutual action of Faraday and Pockels effects in a single Bi4Ge3O12 (BGO) crystal after the wave coupling theory describing these two effects. It is demonstrated that, the expected conversion of arbitrary-to-linear or linear-to-arbitrary polarization state of light can be realized by adjusting the applied electric and magnetic fields.