Abstract
The pyroelectric voltage response to rectangular signals of infrared
radiation is derived using our recent analysis of the response to
a step signal. The response is symmetrical with respect to the electronic
and thermal time constants, taue and tauT of the samples, and with
respect to the times T1 and T2 of irradiation and darkening. When
taue differs appreciably from tauT, the rise of the response at the
onset of irradiation and its fall at the beginning of darkening are
exponentials with the same time constant, which is the smaller one
from among taue and tauT. A rectangular response is obtained when
taue << (T1, T2) << tauT. In this case the peak-to-peak value Vptp
of the response is proportional to taue and independent of the pulse
frequency, as well as of the ratio T1/T2. When T1 and T2 are each
less than the smaller one from among taue and tauT, triangular responses
are obtained, for which Vptp is independent of taue and inversely
proportional to the pulse frequency. Pyroelectric responses obtained
in triglycine sulphate and strontium-barium niobate samples of different
tauT were found to follow the derived expression, and plots of the
measured parameters of the response vs taue, T1/T2, and pulse frequency
show good agreement with the analysis.
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