Abstarct. At high light intensity modulation frequencies, the
photodetector measures the integral energy of the pulsed radiation. In this
case, the photoconductivity kinetics depends mainly on the rate of generation
of charge carriers. Mechanisms of recombination of electrons and holes have
little effect on the photocurrent. The article defines the conditions under
which a photoresistor can be used to reconstruct the time shape of an optical
signal. The shape, frequency and intensity of the pulses vary in an arbitrary
way. The method of reconstructing the shape of an optical signal is applicable
if the intensity varies with frequency ω more than the inverse lifetime of the main charge carriers. That
is, the frequency of the modulated optical pulses is higher than the limit
frequency of the photodetector. The dependence of the light intensity on time
is obtained from the dependence of the current strength on time. Parameters
characteristic of a photodetector fabricated on the basis of Si with In, Ag and
Au recombination centers are used in the calculations. Theoretical studies of
distortions emerging upon the detection of modulated optical signals are
performed. A region of frequencies is obtained for which the method of
obtaining the dependence of the intensity of the exciting pulses on time is
applicable. Increasing the modulation frequency reduces the magnitude of nonlinear,
frequency and phase distortion.
Keywords: impulse excitation, mechanisms of recombination, kinetics of
photoconductivity, linear distortion, nonlinear distortion, phase distortion, pulse
recovery.
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