Three-color common-axis light source suitable for shock wave studies

Abstract

A single-axis, three-color light source system with independent triggers, suitable for multiflash schlieren and other photography is developed. The system enables three primary color exposures to be taken on a common film plane, with each exposure, when separated into the primary color components, representing a monochromatic photograph that can be converted to a gray-scale image. The three primary color light sources on a common optical axis are achieved using a specially designed beamsplitter consisting of dichroic filters mounted against a penta-prism shaped holder. Using this penta arrangement and three independent white light flash sources (e.g., xenon lamps), three images can be recorded at independent times on a single image plane. For schlieren applications, this arrangement ensures that all three images have equal sensitivity because they pass through a common schlieren cutoff, and also have the same axis angle (or perspective) relative to the test section. The system has proven to be both low cost and versatile.