High frequency stochastic resonance (SR) phenomena, associated with fluctuational transitions between coexisting periodic attractors, have been investigated experimentally in an electronic model of a single-well Duffing oscillator which is bistable in a nearly resonant field of frequency omegaF. It is shown that, with increasing noise intensity, the signal-to-noise ratio (SNR) for a signal due to a weak trial force of frequency Omega approximately equal to omegaF at first decreases, then increases, and finally decreases again at higher noise intensities: The behavior is similar to that observed previously for conventional (low-frequency) SR in systems with static bistable potentials. The stochastic enhancement of the SNR of an additional signal at the mirror-reflected frequency |Omega-2omegaF| has also been observed, in accordance with theoretical predictions. Relationships with phenomena in nonlinear optics are discussed.
Translated from the Russian original published in Pis'ma Zh. Eksp. Teor. Fiz. 58, No.2, 145-151 (25 July 1993).