There is provided a flash reflector for maximizing the intensity of light passing into an air sampling chamber of a smoke detector which enables a reduction in power requirements for the light source. The reflector includes a concave reflecting element to focus light from each infinitesimal cross-sectional element off the arc of ionized gas in a flash tube the light output from the whole length of the tube which is optionally of U-shape being focused into the central region of the sampling chamber.
