An experimental evidence of vibrational resonance in a vertical cavity laser

This study presents the first experimental evidence of vibrational resonance (VR) in a real physical system such as VCSEL. The experimental investigations are performed in the setup where the phenomenon of stochastic resonance is studied and characterized in great detail. VR is studied in the laser intensity after polarization selection when two periodic signals with different frequencies are applied to the injection current of the laser. One of periodic signals is the sinusoidal low-frequency (LF) signal with a frequency of 500 Hz and subthreshold amplitude. The second one is the high-frequency (HF) signal with different frequencies ranging from 10 kHz up to 1 MHz, much higher than the frequency of the LF signal. The injection current is chosen in such a way that the laser operates in the regime of polarization bistability, where switching between two states could be induced by applying the deterministic modulation or noise. Different cases of the occurrence of VR are also investigated experimentally.