A pyroelectric detector based on small-signal amplification near period-doubling bifurcations

Recently a nonlinear series resonance circuit has been used to realize a dynamical system, which gives the opportunity to observe period-doubling bifurcations and chaotic behaviour. The nonlinearity was introduced into the system by a capacitor with ferroelectric triglycine sulphate (TGS) as dielectric material. In the vicinity of a period-doubling bifurcation special perturbations of the resonance circuit may be amplified within the system itself. Combining this property of period-doubling dynamical systems with the very good pyroelectric properties of the ferroelectric TGS, a new principle of a pyroelectric detector is introduced. The perturbation of the system is realized by a periodic infrared irradiation of the TGS-capacitor. The resulting electric signal is simultaneously amplified in the circuit by tuning it precisely towards the first period-doubling bifurcation.