Short-wavelength-infrared upconversion edge enhancement imaging based on a Laguerre-Gaussian composite vortex filter

Area of Science:

• Optics and Photonics
• Image Processing
• Nonlinear Optics

Background:

• Spiral phase contrast imaging reveals object gradients but faces limitations in phase mask modulation during reconstruction.
• Current systems struggle to characterize modulation functions, impacting image reconstruction accuracy.
• Existing methods lack the flexibility for diverse imaging modalities.

Purpose of the Study:

• To introduce an innovative nonlinear reconstruction method for edge-enhanced imaging.
• To overcome limitations in phase mask modulation and improve image reconstruction.
• To demonstrate a versatile SWIR edge-enhanced imaging system with tunable contrast and resolution.

Main Methods:

• A nonlinear reconstruction method employing a Laguerre-Gaussian composite vortex filter was developed.
• The method spectrally transforms short-wavelength-infrared (SWIR) signals (1550 nm to 864 nm) via a nonlinear process.
• A silicon charge-coupled device captured the transformed signal, and a spatial light modulator controlled imaging modes.

Main Results:

• The novel filtering method significantly suppresses diffraction noise compared to conventional schemes.
• Image contrast and resolution were substantially enhanced.
• Various imaging modes, including bright-field, isotropic, anisotropic, and directional second-order edge-enhanced imaging, were successfully realized.

Conclusions:

• The proposed nonlinear reconstruction method offers superior performance in edge-enhanced imaging.
• The developed SWIR imaging system provides enhanced contrast, resolution, and imaging flexibility.
• This methodology holds significant potential for applications in AI, medical diagnostics, and non-destructive testing.