ABSTRACT
Noise-like quasi-continuous-wave background (qCWB) in a mode-locked fiber laser mediates various multi-pulse dynamics via long-range inter-pulse interactions. This raises a possibility to control multi-pulse phenomena through manipulation of the qCWB, while it has been rarely studied yet. Here, we investigate the qCWB engineering by imposing optomechanically induced impulsive intensity modulations on the qCWB. The mode-locked pulses excite electrostrictively several transverse acoustic resonance modes inside the fiber cavity, which eventually leads to the formation of sharp qCWB modulations regularly spaced in the time domain. In particular, we experimentally demonstrate that the characteristics of the optomechanical qCWB modulations can be adjusted by controlling the in-fiber optomechanical interactions via changing the structure of the fiber core, cladding, and coating. Our observations are supported by directly measured forward stimulated Brillouin scattering spectra of the intracavity fibers.
ABSTRACT
Photonic devices that exhibit all-optically reconfigurable polarization dependence with a large dynamic range would be highly attractive for active polarization control. Here, we report that strongly polarization-selective nonlinear optomechanical interactions emerge in subwavelength waveguides. By using full-vectorial finite element analysis, we find, at certain core ellipticities (or aspect ratios), that the forward simulated light scattering mediated by a specific acoustic resonance mode is eliminated for one polarization mode. Whereas, that for the other polarization mode is rather enhanced. This intriguing phenomenon can be explained by the interplay between the electrostrictive force and radiation pressure and turns out to be tailorable by the choice of waveguide materials.
ABSTRACT
Mass sensing offering both a broad detection range and a high resolving power is essential for quantitative precision content analysis and high-yield mass production of various kinds of materials. Here, we propose and successfully demonstrate a novel type of simple low-cost optomechanical mass sensing employing an optical displacement detector that consists of a free-space Fabry-Pérot optical cavity and an intra-cavity wedge prism pair, which provides an enhanced resolution and an extended capacity simultaneously. By implementing the null-method-based scheme of mass measurement, we achieve a resolution higher than 5000:1 (mass range from <200 mg to >1 kg) and an excellent linearity of R2>0.99998 in the prototype demonstration.
