Detecting spatial chirp signals by Luneburg lens based transformation medium

Area of Science:

• Optics and Photonics
• Signal Processing

Background:

• Gradient refractive index (GRIN) lenses are used for chirp signal chirpiness detection.
• Existing methods often rely on fractional Fourier transform (FRFT) and are limited by paraxial conditions.

Purpose of the Study:

• To propose a novel non-FRFT mechanism-based GRIN lens for chirpiness detection.
• To overcome the limitations of existing GRIN lens-based methods, particularly the restricted chirpiness detection range.

Main Methods:

• Utilizes transformation optics to adapt a Luneburg lens's focusing capability for chirp waves.
• Employs wavelength sweeping to determine source chirpiness instead of pulse localization.

Main Results:

• Demonstrates a new GRIN lens design that bypasses FRFT limitations.
• Achieves a greatly increased upper limit for chirpiness detection range.

Conclusions:

• The proposed non-FRFT GRIN lens offers a robust and feasible method for enhanced chirp signal chirpiness detection.
• This approach significantly broadens the applicability of GRIN lenses in chirp analysis.