Abstract: Optical detection apparatus is provided which includes a coherent light sce for generating a beam of coherent light. The apparatus further includes a unitized or discrete optical component which receives the generated beam, and projects light thereof which has a particular polarization characteristic into a specified environment. The optical component also functions to receive or absorb light from the environment which has the particular polarization characteristic, and to directably reflect light from the environment which does not have the polarization characteristic. A lens or other light collecting device focuses light reflected by the discrete optical component upon a light detection element. A light conducting path is provided between the coherent light source and the light detecting element to enable generated coherent light to be mixed with the reflected light upon the light detecting element to provide data signals which indicate the presence of an object in the environment.