Speckle characteristics of a broad-area laser diode

摘要

In this paper, far field speckle contrast from a broad area laser diode is measured. The intensity of the incident laser light onto a diffuser is controlled by using polarizer or adjusting input current. A rectangular aperture close to diffuser is used to select different parts of laser light field as illumination spot. The speckle contrast measured for different illuminationspots has no significant change. When the laser diode operates at its typical power output condition, the speckle contrast measured approximately equals 1, while the speckle contrast is depressed tremendously when the laser diode operates with low driving current.