Sensitive method for measuring third order nonlinearities in compact dielectric and hybrid plasmonic waveguides

Area of Science:

• Nonlinear optics
• Materials science
• Nanophotonics

Background:

• Characterizing nonlinear optical properties of waveguides is essential for developing advanced photonic devices.
• Conventional methods face challenges with short propagation distances in metallic and hybrid structures.
• Understanding nonlinearities is key to optimizing light-matter interactions in nanophotonic systems.

Purpose of the Study:

• To demonstrate a highly sensitive method for nonlinear optical characterization of micrometer-long waveguides.
• To apply this method to silicon-on-insulator (SOI) nanowires and hybrid plasmonic waveguides.
• To investigate the potential of hybrid plasmonic structures for efficient nonlinear optical devices.

Main Methods:

• Development of a sensitive nonlinear optical measurement technique.
• Application of the technique to silicon-on-insulator nanowires.
• Application of the technique to hybrid plasmonic waveguides.
• Detection of nonlinear phase shifts down to 7.5 x 10^-4 radians.

Main Results:

• Demonstrated a sensitive method capable of detecting extremely small nonlinear phase shifts.
• Successfully characterized both SOI nanowires and hybrid plasmonic waveguides.
• Achieved high sensitivity advantageous for metallic structures with short propagation lengths.
• Provided the first experimental observation of third-order nonlinearities (χ((3))) in hybrid plasmonic platforms.

Conclusions:

• The developed method offers unprecedented sensitivity for nonlinear optical characterization.
• The findings support the investigation of hybrid plasmonic structures for efficient nonlinear optical applications.
• This work advances the understanding and characterization of nonlinearities in nanophotonic systems.