A FAKE ZOOM LENS FOR FRACTIONAL FOURIER EXPERIMENTS

The fake zoom lens consists of two singlet lenses with focal powers of + 1/f(1). The zoom power ranges from practically -1/f(1) to + 1/f(1). This zoom system is called a ''fake'' because it is too clumsy for standard zoom tasks. But it is useful for the optical implementation of the fractional Fourier transform, and hence, it is useful also for applications of that transform. The zoom lens enables us to vary the degree P of the fractional Fourier transform continuously from -1 to + -1.