The quantum Fourier transform (QFT);Similarities and differences of coherent optical FFT to the QFT. Grover’s search algorithm implemented with a coherent optical correlator. Quantum algorithms requiring bit entanglement -Shor’s algorithm for large number factorisation. Spatial Light Modulator (SLM) pixels placed in a binary superposition state. Addressed with an “interaction free” measurement. Allows exponential increase in processing power. Quantum search algorithm for a decryption problem based on superposition state of coherent wavefront.