Multi-Wavelength Achromatic Imaging With a Pleochroic Confocal Photon Sieve

Achromatic performance is crucial for a variety of multi-wavelength optical imaging applications due to conventional diffractive optical elements suffer from large chromatic aberration. Here, we introduce a multi-wavelength achromatic imaging system utilizing a pleochroic confocal photon sieve (PCPS). In this technique, three foci at three different wavelengths are designed to coexist at various spatial locations on the same plane. Characterization results demonstrate achromatic focus performance at specified wavelengths, and the optimal full width at half maximum (FWHM) of point spread function (PSF) indicate that our device can achieve an optical imaging resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~\mu $ </tex-math></inline-formula>m across all designated wavelengths. Furthermore, we also explored the potential application of the PCPS in single-frame multi-wavelength coherent diffraction imaging (CDI), and preliminary experimental results are presented to confirm the effectiveness of the proposed method. The proposed PCPS exhibits a minimal thickness and demonstrates high design flexibility in focal length and incident wavelengths, providing new opportunities for the development of achromatic imaging systems and RGB holographic displays.