Free-space quantum communication assumes importance as it is a precursor for satellite-based quantum communication needed for secure key distribution over longer distances. Prepare and measure quantum key distribution (QKD) ...

Optical vortices, although being classical, have properties of two-mode entanglement present in quantum states. We have experimentally verified the violation of Bell's inequality using Wigner distribution function for such beams.

Using classical laser beams, we generate a general complex superposition state, cebit, of orbital angular momentum (OAM) of light. We use a nonseparable beam of polarization and OAM generated by a modified Sagnac interferometer ...

Vector vortex beams are classified into four types depending upon spatial variation in their polarization vector. We have generated all four of these types of vector vortex beams by using a modified polarization Sagnac ...

We experimentally demonstrate that the vorticity of light remains preserved even after scattering through a ground glass plate. It shows the robustness of optical vortices along with conservation of orbital angular ...

Spatial modes of light directly give the most easily accessible degree of freedom that span an infinite dimensional Hilbert space. The higher dimensional spatial mode entanglement realized using spontaneous parametric down ...

Optical vortices are singularities in the phase distribution of a light field. At the phase singularity, real and imaginary parts of the field vanish simultaneously and associated wavefront becomes helical. For an optical ...