Realization of Achromatic and Wide-Field Doublet Metalens in Mid-Infrared Spectra

Metalenses has been proposed to replace bulky and heavy refractive lenses. In the mid-infrared (MIR) range, simultaneous realization of wide-field and achromatic imaging for MIR metalense has so far not been achieved. In this letter, we design and fabricate a MIR metalens that achieves achromatic imaging with a field of view (FOV) of 60° in the wavelength range of <inline-formula> <tex-math notation="LaTeX">$10~\mu \text{m}$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$11~\mu \text{m}$ </tex-math></inline-formula>. Experimental results show that the average focusing efficiencies of the metalens are 20.62% at 0° incident angle and 9.1% at 30° incident angle. This metalens provides potential in many applications, such as molecular fingerprint detection, night vision and free space communication.