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Pyroelectricity, one of the least-known properties of solid matter and the pyroelectric effect are both defined and explained in detail. The historical evolution in the study of pyroelectricity and the practical application of pyroelectric IR detectors in various fields are discussed.

One- and 2-D models for the thermal behavior and voltage responsivity of four- and six-layered pyroelectric devices are examined and reported.

Research describing the formation of pyroelectric sensors from the embedding of lanthanum and calcium modified lead titanate (PCLT) in a vinylidene fluoride-trifluoroethylene copolymer (P(VDF-TrFE)) is presented. The sensors were investigated for current and voltage responsivities.

Research is presented describing the development of an array based on a 16 x 16 PVDF ceramic integrated sensor.

An analytical expression for the dynamic point spread functions (PSF's) of the scanner for radiation budget (ScaRaB) FM1 broadband radiometer is derived. The calculated PSF's are validated by comparing ScaRaB broadband radiances with high-resolution METEOSAT 5 broadband radiance estimations. The derived PSF's reduce the relative rms difference between the radiances with 54% for the shortwave radiances and with 8% for the longwave radiances. Index Terms - Convolution, dynamic response, pyroelectric detectors, spatial filters.

The potential use of ceramic compositions of barium strontium titanium oxide as pyroelectric sensor materials was investigated. To this end, the ceramic materials were fabricated in tape-cast and thin film forms. Experimental results showed that the materials possess high pyroelectric coefficients followed by low dielectric constant and low dissipation factor. The dielectric constant and loss tangent of the materials can be reduced by doping barium strontium titanium oxide with magnesium oxide, resulting in an increase in the pyroelectric figure of merit.

Ferroelectric thin films of BaxSr(sub1-x)TiO(sub3) having composition gradients normal to the growth surface have been prepared on platinum substrates by metalorganic decomposition. The application of an ac field achieving effective pyroelectric coefficients up to 0.06 muC/Cm(super2)K, compared to a value of just -0.003 muC/cm(super2)K for conventional pyroelectric coefficients.

Pyroelectric body sensors are used in many fields and their high sensitivity in the wide spectral region allows the development and production of portable and economical thermal images. The most important mechanisms of heat losses in pyroelectric sensors are considered and their influence on the responsivity is estimated. Each of the mechanisms corresponds to certain frequency range, with predominant frequency response types.

Uncooled pyroelectric infrared detectors based on semiconducting Y-Ba-Cu-O were studied by examining four different structures in various samples. The temperature dependence of the pyroelectric sensors were also determined. Results showed a fairly constant optical response with respect to temperature over a wide range at about 300 deg K. However, responsivity of another device with a different geometry decreased rapidly at about 304 deg K. The wavelength-dependent response also decreased when the silicon transmission increased.

Research was conducted to investigate the growth, fabrication and characterization of thin-film heterostructure pyroelectric IR detectors based on Sb- and Mn-doped PbZrTiO3 (PMSZT) films integrated to conducting an oriented YBa2Cu3O7 (YBCO) electrodes. The infrared photoresponse of the PMSZT/YBCO heterostructure revealed that the thin-film detector is suitable for IR detector applications in temperature environments below the PMSZT film Curie temperature of ~170 degrees C.

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.

Ferroelectric materials are distinguished by their piezoelectric and pyroelectric properties, and have been widely applied in remote thermometry and detection and measurement of nonionizing radiation. A pyroelectric detector for measuring energy fluence rates of x-ray pulses in the diagnostic energy range, is described. Detector response conformed to thermal and electrical analysis theoretical predictions.

A numerical scheme to correct for the delayed response of thermal solar radiation sensors is discussed. The proposed scheme employs only information that can be obtained from the response to a step input and does not require any auxiliary measurements. Furthermore, the scheme is applicable to instruments with any number of time constants and avoids the need for high order numerical derivatives. The development of such a scheme is motivated by a study of the Eppley Normal Incidence Pyrheliometer, which cannot be described accurately by a two-exponential model.

A study was done on the pyroelectric coefficient of the (PbO)x (GeO2)8-x ceramics as a function of PbO or GeO2 content close to x = 5. It was shown that the value of the pyroelectric coefficient as a function of the PbO contetn x increases up to x =5 and decreases above with an irregularity around x = 5. The electrical activity of ceramics is approximately two orders of magnitude higher than in the monocrystal. This result suggests that the grain boundaries are important for the conductivity mechanism.

The feasibility of using the pyro-optic analog of pyroelectric devices in infrared imaging is investigated via the analysis of temperature dependence of the refractive indices of several pyro-optical materials. The wavelength of the maximum temperature dependence of antimony sulfur iodide, molybdenum disulphide and bismuth vanadium tetraoxide semiconductors were obtained via spectroscopic ellipsometry. Results were then related to the reflectance coefficients and refractive indices of these materials. Temperature variations between 0.001 and 0.01 degrees centigrade can be detected via thermal imaging as long as the reflectance coefficient is monitored.

Two-dimensional modeling of the nonstationary thermal state and voltage responsivity of elements used in solid-state pyroelectric focal plane arrays is described and discussed.

The analysis of the design and construction of two kinds of sensitive high- T(c) bolometers, based on epitaxial YBa2Cu3O(7 - delta) (YBCo) thin-film transition edge thermometers on a 20 micrometer thick sapphire substrate, reveals that the bolometers are more sensitive than room temperature detectors over wavelengths 20-300 micrometer. The determination of the water vapor transmittance spectrums indicates the sensitivity of the two devices and their application in far infrared spectroscopy.

A report on how a paired-crystal pyroelectric source can be used to approximately double the endpoint x-ray energy, in addition to doubling the x-ray yield, versus a single-crystal source is presented. A spectrum showing the fluorescence of the K shell of thorium and K shell of lead is shown as an example of the advantage of a paired-crystal system.

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.