Abstract: A pyroelectric detector with significantly reduced microphonic noise sensvity that includes a pyroelectric detector element constructed from a z-cut LiNbO.sub.3 and LiTaO.sub.3 electret. Selective domain reversal is accomplished in the electret by applying an electric field. Electrodes are attached to either surface of the electret spanning the domain reversed region and a portion of the original domain region to create areas of equal and opposite sensitivity. The detector is mounted in an electrically grounded container or housing. The detector may also be constructed having multiple detector regions to accomodate resonant frequencies of the electret or to function as a position sensor.