Silicon lattice layer regulation: A close-to-atomic-scale method for optimizing infrared optical properties

•Infrared optical properties optimization of various Si lattice structures are investigated.•Close-to-atomic method(IBF and CMP) is imported to regulate various lattice layers on Si surface.•Removal of amorphous layer above the low-density layer improve the reflectivity notable.•Low-density(about 1 nm) layer and transition layer(about 1 nm) are conducive for optimize the infrared optical properties(reflectivity and photo-thermal absorption). A fundamental challenge in optimizing the infrared optical properties of monocrystalline Si(100) reflectors is achieving high infrared reflection and low photo-thermal absorption. These requirements have been traditionally satisfied by removing various surface defects to obtain a perfect lattice structure. To supersede the traditional logic of “non-defect surfaces,” a surface lattice structure scheme, “Si lattice layer regulation,” is proposed. This paper presents a close-to-atomic-scale method for regulating multilayer Si lattices. First, a “multilayer lattice” (disordered, low-density, and transition layers) is introduced by ion beam figuring as a regulation base. Subsequently, the infrared optical properties are improved by reducing the disordered layer above the low-density layer using chemical–mechanical polishing. An experimental comparison proves that the scheme is effective: the reflectivity of the new surface developed in this study increases by 10 % (from 900 to 1500 nm (testing band)), and the photo-thermal absorption of the surface is controlled at 0.116 ppm. Therefore, the optical properties of monocrystalline Si can be optimized by regulating the thickness of the Si atomic layers with different densities. A lattice layer based on the field of materials science (e.g., material band gap and electronic property regulation) is introduced to an optical field with high infrared optical properties on Si surfaces. This allows the optical processing to enter an emerging “close-to-atomic-scale” manufacturing dimension. This work also opens up advanced prospects in the fields of high-energy optics and X-rays and directs research on atomic structure regulation toward a completely new area of optics.