Optical parametric oscillators (OPOs) have become standard source of coherent radiation inaccessible to ordinary lasers. Based on nonlinear optical effect, the OPOs convert a ffxed pump laser wavelength to a wide band of ...

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 ...