Optical acoustic interaction in subwavelength acoustic and optical nanofiber interferometer excited by surface acoustic waves

The surface acoustic waves (SAWs) orthogonal to the surface’s normal direction have been used in generators and hybrid quantum devices. High nonlinearity As2Se3 dual-core nanofibers allow for externally pumped (via SAWs) forward Brillouin scattering with low thermal noise under 1mW optical power. Core dimensions of the nanofibers are comparable to the probe wavelength of 1.55 µm, at ~1.4µm. These dimensions enable entangled states of light and offers an optical interferometer for acoustic waves of 100 MHz with a 40 µm acoustic period, ~28x the core diameter, enabling sub-acoustic optical wave interactions between the two cores, and a 2nd order field correlation for detection. In conjunction with balanced detection (BD), a 4th order field quantum correlation at high sensitivity detection is achieved. This novel approach uses 1 mW optical power and 1 mV pumping the SAW cavity at its resonant frequency, we demonstrate squeezed light at room temperature, reducing the noise floor to <1 dB above the dark noise limit. This opens doors for super narrow optical filters (Hz range) at room temperature by quantum device for high precision sensing. We proposed a subwavelength dual-core nanofiber device together in both optical and acoustic domain to detect optical and acoustic waves.