Holographic acoustic-signal authenticator

Most optical information processors deal with text or image data, and it is very difficult to deal experimentally with acoustic data. Therefore, optical advances that deal with acoustic data are highly desirable in this area. In particular, the development of a voice or acoustic-signal authentication technique using optical correlation can open a new line of research in the field of optical security and could also provide a tool for other applications where comparison of acoustic signals is required. Here, we report holographic acoustic-signal authentication by integrating the holographic microphone recording with optical correlation to meet some of the above requirements. The reported method avails the flexibility of 3D visualization of acoustic signals at sensitive locations and parallelism offered by an optical correlator/processor. We demonstrate text-dependent optical voice correlation that can determine the authenticity of acoustic signal by discarding or accepting it in accordance with the reference signal. The developed method has applications in security screening and industrial quality control.