title: Influence of optical forces on nonlinear optical frequency conversion in nanoscale waveguide devices.
abstract: We theoretically investigate the influence of optical gradient forces on nonlinear frequency conversion in a typical nanoscale optomechanical system, which consists of two parallel, suspended waveguides. The waveguides deform with the input power and the phase-matching wavelength changes along the waveguides. Utilizing the spread of deformations collectively allows phase matching over a wider range of pump wavelengths. The third harmonic phase-matching wavelength shift can be as large as 3.6 nm/mW when the waveguide length is 100 μm and the initial gap is 150 nm. It is analogous to chirping the poling period of quasi-phase-matched devices to extend their bandwidths, and allows broad third harmonic to be generated for uses such as biological spectroscopy. Finally, we discuss the conversion efficiency and the optimal phase-matching wavelength with a single-frequency pump.
authors.forename: Zhen-xing
authors.initials: ZX
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.forename: Shi-han
authors.initials: SH
authors.lastname: Tang
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: Yan-qing
authors.initials: YQ
authors.lastname: Lu