Grover's search algorithm: An optical approach
P. G. Kwiat, J. R. Mitchell, P. D. D. Schwindt, A. G. White · Journal of Modern Optics · 2000
The essential operations of a quantum computer can be accomplished using solely optical elements, with different polarization or spatial modes representing the individual qubits. We present a simple all-optical implementation of Grover's algorithm for efficient searching, in which a database of four elements is searched with a single query. By ‘compiling’ the actual set-up, we have reduced the required number of optical elements from 24 to only 12. We discuss the extension to large databases, and the limitations of these techniques.