Abstract

Conventional or phase-only correlators suffer from the requirement of fabrication and accurate alignment of the complex filter in the Fourier plane. A joint transform correlator, on the other hand, does not require fabrication of any complex filter and therefore is more attractive for real-time uses. In a JFT setup, the joint transform power spectrum of the input objects (i.e., the reference object and the input object) is generated and then, by performing subsequent an inverse Fourier transform on these interference fringes, the cross-correlations between these objects are produced.¹ In our setup, the LCLV is used to generate the intensity fringes, and then used to provide gain. Unlike other methods no optic-to-electronic conversion is performed, since the function of the square law detector is preformed by the LCLV as required by the JFT. Therefore this system is an all-optical setup. Nonlinear operation is then achieved by changing the power of the write beam. The correlation output is fed back to observe its effect on the correlation peak.²

© 1991 Optical Society of America