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We have developed a diffractive micromachined chopper (DMC) for an IR wavelength of ~10 [[micro]meter]. This device operates mechanically by movable reflection grating beams. It modulates the diffraction efficiency by controlling the displacement of grating beams by an electrostatic force. For a [CO.sub.2] laser beam, a high modulation efficiency of 84% with an -0.8-dB small insertion loss was obtained by detecting 0th-order diffracted light. A novel pyroelectric IR microsensor with a DMC and a diffractive multilevel Si microlens was proposed and it demonstrated the detection of human existence.

We have designed and built a pyroelectric optical detector for use as a transfer standard for the calibration of optical power meters. The pyroelectric element is made from lithium tantalate (LiTa[O.sub.3]). Gold black is used as the optical absorber in a multiple reflection wedge-shaped trap structure, with a 5-mm diameter input aperture and an f/4 field-of-view. The detector's spatial responsivity varies less than 1%. The responsivity as a function of wavelength varies less than 1% over a range from 0.45-1.55 [[micro]meter] and less than 4% from 1.55-10.6 [[micro]meter]. The measured noise equivalent power (NEP) is 5x[10.sup.-8] W/[Hz.sup.1/2]. For this wavelength range and detector area, the measured NEP and spatial uniformity represents a significant improvement over comparable predecessors.