Lim, O-KBoland, BSaffman, MarkKrolikowski, Wieslaw2015-12-132015-12-131464-4258http://hdl.handle.net/1885/79501We demonstrate the generation and frequency doubling of unit charge vortices in a linear astigmatic resonator. The topological instability of the double charge harmonic vortices leads to well separated vortex cores that are shown to rotate, and become anisotropic, as the resonator is tuned across resonance.Keywords: Anisotropy; Cavity resonators; Diffraction; Gaussian noise (electronic); Holographic interferometry; Magnetic resonance; Nonlinear optics; Optical image storage; Optical instrument lenses; Optical pumping; Optically pumped lasers; Second harmonic generati Optical vortices; Second harmonic generation; Vortex splitting200410.1088/1464-4258/6/5/0322015-12-11