Large longitudinal electric fields (Ez) in silicon nanowire waveguides

Area of Science:

• Photonics and Nanotechnology
• Computational Electromagnetics

Background:

• Silicon nanowire waveguides are crucial for integrated photonics.
• Understanding electric field distribution is key to controlling nonlinear optical effects.

Purpose of the Study:

• To demonstrate and quantify strong longitudinal electric fields (E(z)) in silicon nanowire waveguides.
• To investigate the impact of E(z) on waveguide nonlinearity.
• To explore methods for controlling E(z) using waveguide geometry.

Main Methods:

• Numerical computation of electric field distributions.
• Analysis of waveguide geometry effects on field amplitudes.
• Investigation of nonlinear effects influenced by E(z).

Main Results:

• Strong E(z) components were found, reaching 97% of transverse fields.
• Terminated waveguides create dominant E(z) in free space.
• E(z) significantly influences waveguide nonlinearity.
• Dual waveguide designs allow control over E(z) strength and symmetry.
• Engineered E(z) shows sharp peaks beyond the diffraction limit.

Conclusions:

• Longitudinal electric fields are a significant factor in silicon nanowire waveguide performance.
• Precise engineering of waveguide geometry offers control over E(z).
• This control enables enhanced manipulation of nonlinear optical phenomena and sub-diffraction field localization.