论文标题
出色的衍射透镜极限
Achromatic diffractive lens limits
论文作者
论文摘要
近年来，有许多有关出色金属和衍射镜片的报道。但是，已经证明了这种出色的扁平镜头的（如果有的话）的实际应用（如果有的话），这引发了有关这些镜头为涉及宽带照明的现实世界案例提供解决方案的潜力的问题。最近的纸张对出色金属的性能限制了限制。但是，此极限对于衍射镜头也有效吗？不一定是这样。在本文中，我们得出了有关出色的衍射透镜性能的限制。特别是，我们表明，出色的衍射镜可以覆盖广泛的光谱范围，仅受到与特征深度和大小相关的制造限制造成的效率损失的限制。另一方面，我们表明，只有在非常低的菲涅耳编号下，出色的衍射镜头才能提供接近衍射有限的性能，即它们不能同时提供较大的聚焦功率和宽带响应。然后，我们继续比较出色的金属镜和衍射透镜的极限，以了解不同类型的扁平透镜的潜力。我们的发现可能为更好地评估平面镜头性能，了解其功能和局限性以及探索新颖的设计概念和应用而为基础奠定了基础。
Over the recent years, there have been many reports of achromatic metalenses and diffractive lenses. However, very few (if any) practical applications of such achromatic flat lenses have been demonstrated, which raises questions about the potential of these lenses to provide solutions for real world cases which involve broadband illumination. A recent paper placed limits on the performance of achromatic metalenses. However, is this limit also valid for a diffractive lens? Not necessarily so. In this paper we derive the limits on the performance of achromatic diffractive lenses. In particular, we show that achromatic diffractive lenses can cover a wide spectral range, limited only by loss of efficiency caused by manufacturing limitations related to feature depth and size. On the other hand, we show that achromatic diffractive lenses can provide near diffraction limited performance only at very low Fresnel numbers, i.e. they cannot provide large focusing power and broadband response simultaneously. We then go on to compare the limits of achromatic metalenses and diffractive lenses, in attempt to understand the potential of different types of flat lenses. Our findings may set the ground for better evaluation of flat lens performance, understanding of their capabilities and limitations, and for exploring novel design concepts and applications.
