Continuous-wave laser beam fanning in organic solutions: a novel phenomenon.

If a low-power cw Ar(+) laser beam (~50 mW) is sent horizontally and focused on the entrance side of a cuvette containing an absorptive solution, the beam fans into the lower half of the cuvette instead of propagating through and forming self-phase-modulation fringes. We call this phenomenon self-beam fanning, which has been observed in several organic solutions. We present here several experimental results and a descriptive model of the phenomenon.

Energy-transfer measurement and determination of the phase shift between the holographic grating and the fringe pattern in photorefractive materials.

We describe a novel accurate method to measure energy transfer between two beams coupling in photorefractive materials. We have used this method to measure the on-line energy-transfer signal in an electrically poled BaTiO(3) crystal and to record the growth of the grating responsible for energy transfer. We also used this technique to determine the phase shift between the grating that is written in the crystal and the fringe pattern responsible for writing that grating. The phase shift in our BaTiO(3) is found to be 90 degrees , as predicted by the diffusion model.

Compact in-line laser radial shear interferometer.

A compact in-line radial shearing interferometer using laser as a light source is presented. The interferometer is made out of a cube-type beam splitter so that the two opposite surfaces are generated with different curvatures while the normal to the entrance and exit surfaces are in the same line. The interferometer is simple to make and easy to align. Aberration analysis of the interferometer is also presented. Some applications of the interferometer for testing lenses and infrared optical systems and for accessing the quality of an emerging wave front from the exit slit of a monochromator are suggested.