Giant enhancement of second-harmonic generation in multiple diffraction orders from sub-wavelength resonant waveguide...

Area of Science:

• Nonlinear Optics
• Materials Science
• Photonics

Background:

• Second-harmonic generation (SHG) is a key nonlinear optical process for frequency conversion.
• Enhancing SHG efficiency is crucial for developing advanced photonic devices.
• Dielectric structures offer potential for efficient light manipulation.

Purpose of the Study:

• To demonstrate a purely dielectric resonant waveguide for enhanced second-harmonic generation.
• To quantify the efficiency enhancement compared to a reference surface.
• To investigate the directional emission properties of the structure.

Main Methods:

• Fabrication of a dielectric resonant waveguide structure.
• Experimental measurement of second-harmonic generation efficiency.
• Characterization of the angular distribution of emitted second-harmonic radiation.

Main Results:

• Achieved an efficiency enhancement factor of at least 5500 for second-harmonic generation compared to a flat reference.
• Observed directional emission of second-harmonic radiation in four distinct directions.
• Demonstrated that directional emission occurs when fundamental radiation is incident at the resonant angle.

Conclusions:

• The demonstrated dielectric resonant waveguide significantly enhances second-harmonic generation efficiency.
• The structure exhibits unique multi-directional emission properties.
• This work paves the way for novel photonic devices utilizing efficient frequency conversion and tailored light emission.