Effects of squeezed-film damping on the optomechanical nonlinearity in dual-nanoweb fiber

摘要

The freely-suspended glass membranes in a dual-nanoweb fiber, driven at resonance by intensity-modulated light, exhibit a giant optomechanical nonlinearity. We experimentally investigate the effect of squeezed-film damping by exploring the pressure dependence of resonant frequency and mechanical quality factor. As a consequence of the unusually narrow slot between the nanowebs (22 μm by 550 nm), the gas-spring effect causes a pressure-dependent frequency shift that is ∼15 times greater than typically measured in micro-electro-mechanical devices. When evacuated, the dual-nanoweb fiber yields a quality factor of ∼3 600 and a resonant optomechanical nonlinear coefficient that is ∼60 000 times larger than the Kerr effect.