Solar Optics: Fun With the Sun

Continuous turning of the cavity mirror: HG(0,1) mode turns into a doughnut beam, and then into an HG(1,0) mode

Interference patterns of various transverse modes (no dove prism)

Interference patterns of doughnut beam with dove prism in one arm of interferometer (notice the forks)

Interference pattern of two collinear, opposite helicity vortices (if they are indeed vortices?). The pattern counter-rotates as you pull one mirror with a rubber band.

Interference patterns of doughnut beams with dove prism in the path of one beam. The fringes fork along two lines making an 'X' through the beam.

Sequence of images of two collinear vortices of opposite charge as the phase difference is varied. The result is a rotating first-order HG mode.