Bicell pyroelectric optical detector made from a single LiNbO3 domain-reversed electret

Using electric-field poling at room temperature, we selectively reversed the direction of the spontaneous polarization in a 200-mu m-thick, z-cut LiNbO3 electret to produce a bicell pyroelectric detector. The detector required only a single set of electrodes, one electrode on the front surface and one on the back surface. Microphonic noise that is typical of monocell pyroelectric detectors is reduced in the present device. Our spatial uniformity data indicate that the optical response of one half of the bicell detector area was equal to and opposite the other half within 1.2%. The microphonic suppression of the bicell pyroelectric detector was less than -36 dB from 10 to 50 Hz and less than -118 dB at 35 Hz of that of a reference monocell pyroelectric detector. The substrate thickness is significantly greater than those of other domain-engineered pyroelectric detector designs and allows us to build practical, large-area detectors for radiometric applications. (C) 1998 Optical Society of America.