Abstract: An optical system for moving a focal point along an axis employs an input telescope having a variable lens separation and a fixed field lens separated from the telescope by the sum of the focal lengths of the field lens and the second lens of the telescope. The focal spot maintains a constant size as it moves. If two input beams are used, the crossing angle of the beams remains constant.

Abstract: An optical beam splitter divides an incoming converging optical beam into two or more spatially separated output beams that both have a desired attenuation ratio between consecutive output beams and also focus all output beams in substantially the same plane.

Abstract: A method for generating coherent anti-Stokes Raman radiation having high spatial resolution is disclosed. Three input beams are focused into an interaction zone where three wave mixing occurs to generate a coherent anti-Stokes Raman beam. The angular separation between the focused beams is controllable according to simple geometric relationships for phase matching the beams.

Abstract: In an optical system, primarily adapted for use in light scattering diagnostics e.g. Raman, Rayleigh, laser fluorescence, an obscuration means is placed between the sample volume (or object) and a light collecting means (such as a lens or mirror) to limit the backscattered light collection passed through an aperture to a shorter length along the optical axis, thereby increasing the spatial resolution of the system. In general, the effective obscuring diameter is determined as twice the ratio of the square of the distance between the image of the aperture within the sample volume and the collection means to the distance between the collection means and the aperture, times the ratio of the aperture diameter to the desired length of sample volume. In refractive embodiments, obscuration is provided by an opaque disc adjacent a collection lens. In a second embodiment, obscuration is provided by a coaxial arrangement of independent fiber optical light pipes.