Manipulating continuous optical spectra in the wave vector domain by metalens

Area of Science:

• Optics and Photonics
• Metasurface Technology
• Spectroscopy

Background:

• Phase singularities in light fields cause rapid phase variations and sharp local k-vector peaks.
• Understanding the relationship between light intensity and k-vector distribution is crucial for optical manipulation.

Purpose of the Study:

• To investigate the generation and manipulation of sharp k-vector peaks from light intensity distributions.
• To demonstrate a metalens-based approach for transforming optical spectra into the wave vector domain.
• To enhance spectral resolution for metasurface spectroscopy applications.

Main Methods:

• Transformed spatial intensity distribution into wave vector distribution.
• Identified local k-vector peaks at points of minimum light field intensity.
• Designed a metalens to generate wavelength-dependent k-vector peaks.

Main Results:

• Established that local k-vector peaks form at minimum light intensity points, sharpening with proximity to phase singularities.
• Demonstrated control over k-vector peak characteristics by manipulating minimum optical field intensity.
• Achieved high spectral resolutions (optimal 0.027 nm) over a broad wavelength range (800-810 nm) using the metalens.

Conclusions:

• The study provides a new method to transform full-band continuous optical spectra from the spatial to the wave vector domain.
• The metalens design enables precise control and manipulation of k-vector peaks, offering a new tool for optical analysis.
• This approach significantly improves spectral resolution, paving the way for advanced metasurface spectroscopy.