An optical implementation of the fractional Fourier transform (FRT) with broadband illumination is proposed by use of a single imaging element, namely, a blazed diffractive lens. The setup displays an achromatized version of the FRT of order <i>P</i> of any two-dimensional input function. This fractional order can be tuned continuously by shifting of the input along the optical axis. Our compact and flexible configuration is tested with a chirplike input signal, and the good experimental results obtained support the theory.
© 2000 Optical Society of America
(050.1940) Diffraction and gratings : Diffraction
(070.2580) Fourier optics and signal processing : Paraxial wave optics
(070.6020) Fourier optics and signal processing : Continuous optical signal processing
(100.0100) Image processing : Image processing
Enrique Tajahuerce, Genaro Saavedra, Walter D. Furlan, Enrique E. Sicre, and Pedro Andrés, "White-Light Optical Implementation of the Fractional Fourier Transform with Adjustable Order Control," Appl. Opt. 39, 238-245 (2000)