Centimeter-size achromatic metalens in long-wave infrared

Area of Science:

• Optics and Photonics
• Materials Science
• Infrared Technology

Background:

• Metalenses offer advantages in size and weight compared to traditional optics.
• Large-aperture achromatic metalenses face challenges with dispersion range and computational demands.
• Long-wave infrared (LWIR) imaging requires advanced optical solutions for compact systems.

Purpose of the Study:

• To propose a device-optimizing framework for fabricating centimeter-size achromatic metalenses.
• To address chromatic aberrations in the long-wave infrared (8-12 μm) spectrum.
• To enable the development of lightweight and ultra-thin LWIR imaging systems.

Main Methods:

• Engineered phase dispersion and amplitude transmittance using a computational framework.
• Optimized group delay and dispersion phase for chromatic aberration correction.
• Fabricated and characterized all-silicon metalenses with diameters of 3.18 cm and 6.36 cm.

Main Results:

• Achieved diffraction-limited tight-focusing with normalized focal length shift < 3.3 × 10^-4.
• Demonstrated effective chromatic aberration correction in the 8-12 μm LWIR range.
• Verified thermal imaging performance on targets with features > 2 mm.

Conclusions:

• The proposed framework successfully creates large-aperture achromatic metalenses.
• These metalenses are suitable for high-performance, lightweight LWIR imaging systems.
• Findings pave the way for advanced compact optical devices in the infrared spectrum.