Pseudo-spin light circuits in nonlinear photonic crystals.

Area of Science:

• Photonics
• Nonlinear Optics
• Materials Science

Background:

• Photonic circuits commonly rely on modifying linear permittivity for light control, leading to non-homogeneous media.
• Achieving complex light control in miniaturized devices requires robust guiding mechanisms.

Purpose of the Study:

• To propose and experimentally realize photonic circuits guided entirely by nonlinear interactions in a homogeneous medium.
• To demonstrate dual-wavelength light beam guidance and optical control using nonlinear effects.
• To explore the analogy between nonlinear photonic guiding and spin current transport in magnetic domain walls.

Main Methods:

• Utilized custom-poled nonlinear photonic crystals to guide frequency superposition beams acting as pseudo-spins.
• Experimentally guided beams over distances exceeding four Rayleigh lengths.
• Employed optical pumping to switch guiding properties based on the relative phase of participating wavelengths.

Main Results:

• Achieved dual-wavelength light guidance in a homogeneous refractive index medium driven solely by nonlinear interaction.
• Demonstrated that guiding properties are controllable via the relative phase of the wavelengths, switchable with an optical pump.
• Realized a pseudo-spin directional coupler using parallel-poled nonlinear photonic crystal structures.

Conclusions:

• Nonlinear interactions in homogeneous media offer a novel approach for photonic circuit design, enabling unprecedented light control.
• The developed mechanism provides robust control over frequency superposition states of light and mimics spin-dependent potentials.
• This work opens new avenues for emulating complex magnetic domain wall structures and advancing photonic technologies.