Optical heterodyne detection system and method

A heterodyne system to achieve detection of an optical-signal wavefront using a plurality of discrete detector elements operating in parallel with correct local oscillator amplitude distributions and phase relationships between the optical-signal wavefront and local-oscillator wavefronts, said system comprising:

• an array of discrete detector elements operating in parallel, each element of the array being operable to mix a local oscillator wavefront with said optical-signal wavefront to produce an electrical output with correct amplitude and phase relationships with the outputs from the other detector elements of the array;
• and
• a local oscillator to produce an electromagnetic field which is transformed by optical elements within the system to produce an aligned local-oscillator phase distribution simultaneously over each of the discrete detector elements of the array to detect simultaneously a number of separate spatial resolution elements of the optical-signal wavefront.

A process of providing a computer generated binary holographic grating that when illuminated with laser radiation will generate a plurality of local oscillator wavefronts of predetermined amplitude distributions and relationships, that comprises:

• forming a binary surface relief pattern having a predetermined two-dimensional fringe distribution that operates on the laser radiation incident thereon to generate the plurality of local-oscillator wavefronts of predetermined amplitude distributions and phase relationships, which process uses a calculated Fourier transform pattern of the required amplitude and phase distribution to generate the plurality of local oscillator wavefronts;
• and
• applying coding to convert a complex valued Fourier transform pattern into a real non-negative holographic binary phase pattern in such a way that the desired complex valued wavefront can be optically produced.