Broadband Achromatic Metalens in Mid-Wavelength Infrared

Metasurface provides a powerful platform to correct the chromatic aberration of conventional lenses in a flexible, integratable, and ultra-compact manner. Mid-wavelength infrared has promised many exciting applications ranged from molecular fingerprint detection to low-light-level night vision. Developing broadband achromatic metalens in mid-wavelength infrared becomes necessary to meet the increasingly urgent demands on high performance photonic devices. Here, we demonstrate the broadband achromatic metalenses from 3.5 to 5 mu m with all-silicon metasurfaces. Large phase dispersion control range is achieved to realize metalenses with both large numerical apertures and sample sizes while maintaining high focusing efficiency. The experimental results verify the diffraction-limited achromatic focusing and imaging of the metalenses in mid-wavelength infrared. Additionally, we also demonstrate the versatility by successfully implementing the generation of the broadband achromatic focusing optical vortex (L = 2). This work represents a solid step toward practical implementation of metalens and may find applications in mid-wavelength infrared imaging and detections.

Automated summary

The article demonstrates the use of all-silicon Metasurfaces to create broadband achromatic metalenses in the mid-wavelength infrared range. These metalenses achieve high focusing efficiency and diffraction-limited imaging, showing promise for applications in mid-wavelength infrared imaging and detection.