Interference between stretched and original pulses

An off-axis holographic recording method for fast-moving objects that has a time resolution of several picoseconds and a large depth of field is sugge sted. Two different but mutually coherent laser pulses, the original pulse (20 ps) and a stretched pulse (60 ps), are interfered. The short pulse dete rmines the resolution, and the stretched pulse increases the held depth. In terference patterns between the short and the expanded pulses, for lambda = 1.064 mu m and lambda = 0.532 mu m, are demonstrated. (C) 2000 Optical Soc iety of America OCIS codes: 320.7100, 120.3180, 090.0090, 110.6880.