Design of a broadband dual-channel panoramic system with a double-layer diffractive optical element

Area of Science:

• Optical engineering
• Imaging systems
• Diffractive optics

Background:

• Panoramic imaging systems are crucial for applications requiring wide field-of-view coverage.
• Broadband chromatic aberration is a significant challenge in optical system design.
• Existing systems may have limitations in low-illumination or blind-spot coverage.

Purpose of the Study:

• To develop a dual-channel panoramic annular lens (PAL) system for blind-area-free continuous imaging.
• To compensate for broadband chromatic aberration using a novel diffractive optical element.
• To achieve high imaging performance across a broad spectral range (450-1550 nm).

Main Methods:

• Design and integration of a dual-channel PAL system.
• Incorporation of a double-layer diffractive optical element (DLDOE) for chromatic aberration correction.
• Optimization of the DLDOE based on comprehensive bandwidth integral average diffraction efficiency (CBIADE).

Main Results:

• Achieved angle-bandwidth-averaged diffraction efficiencies of 97.95% (panoramic) and 98.08% (front channel).
• Demonstrated high imaging performance with MTF > 0.51 (panoramic) and > 0.30 (front) at 100 lp/mm.
• Maintained low F-θ distortion (< 3.88%) across the system.

Conclusions:

• The developed dual-channel PAL system offers compact structure and high imaging quality.
• The DLDOE effectively compensates for broadband chromatic aberration.
• The system shows potential for challenging low-illumination imaging applications like surveillance and autonomous driving.