Title :
Transformation of topological charge in optical down conversion
Author :
Maleev, I.D. ; Deykoon, A.M. ; Swartzlander, G.A., Jr.
Author_Institution :
Dept. of Phys., Worcester Polytech. Inst., MA, USA
Abstract :
Summary form only given. Spontaneous degenerate parametric scattering [down-conversion] is a 3-photon process with one pump photon of frequency 2/spl omega/ and two output photons of frequency /spl omega/. An optical vortex is defined as a beam containing a phase singularity, i.e. the change of phase around the center of the beam equals 2 /spl pi/m; where the integer m is the topological charge. Our experimental results using a BaB/sub 2/O/sub 4/ crystal under type II phase matching conditions and numerical simulations suggest that the vortex in the pump beam is transformed into a speckle-like structure, effectively that structure is composed of randomly occurring vortex and Gaussian beams. The two down-converted output signals (signal and idler) appear as rings of orthogonal polarization and, therefore, can be easily distinguished.
Keywords :
barium compounds; laser beams; optical frequency conversion; optical materials; optical phase matching; optical pumping; topology; vortices; 3-photon process; BaB/sub 2/O/sub 4/; BaB/sub 2/O/sub 4/ crystal; Gaussian beams; down-conversion; down-converted output signals; optical down conversion; optical vortex; orthogonal polarization; phase singularity; pump beam; pump photon; randomly occurring vortex; speckle-like structure; spontaneous degenerate parametric scattering; topological charge; type II phase matching conditions; Adaptive optics; Laser excitation; Nonlinear optics; Numerical simulation; Optical frequency conversion; Optical pumping; Optical scattering; Optical vortices; Particle scattering; Polarization;
Conference_Titel :
Quantum Electronics and Laser Science Conference, 2000. (QELS 2000). Technical Digest
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
1-55752-608-7
