Device for measuring the duration of very short light pulses, for example lasers - pulses

摘要

1,260,901. Measuring the duration of a light pulse. COMPAGNIE GENERALE D'ELECTRICITE May 13, 1969 [May 31, 1968], No.24443/69. Heading G1A. In an arrangement for measuring the duration of a very short light pulse the pulse 305 is split into two pulses 306, 307 each is applied to an optical delay line 308, 309 to produce a series of pulses of different repetition frequency, and the pulses of the two series are combined and supplied to a detector 313, the detector output signal being a function of the varying pulse overlap and thus an indication of the pulse width. Pairs of optical delay lines in which the delay in one is adjustable are described with reference to Figs.4-8 (not shown) and each delay line may comprise a reflecting mirror and a parallel halfsilvered mirror into which a light pulse is introduced at a slight angle to the normal to produce a chain of pulses, and in the adjustable line, the distance between the two mirrors may be adjusted in steps by for example a micrometer, steps being necessary to prevent the development of fringes. Other arrangements for achieving different delay times may be chambers filled with gases at different pressures or a low-loss birofringent crystal the outside of which is lightly silvered.