Optically transmissive devices and fabrication

#A conventional electromagnetic metasurface refers to a type of artificial sheet material having a sub-wavelength thickness. Metasurfaces can be either structured or unstructured with subwavelength-scaled patterns in the horizontal dimensions.

#In one conventional application, metasurfaces are slabs of subwavelength thickness containing subwavelength in-plane features (so-called meta-atoms) that are used to realize a desirable functionality by local modification of the interaction between the slab and incident electromagnetic fields. Due to the subwavelength thickness, this interaction can be well modeled by equivalent surface boundary conditions, dictated by the metasurface implementation.

#The mid IR (Infrared) band of electromagnetic radiation is a particular useful part of the spectrum. It can provide imaging in the dark, tracing of heat signatures, sensitive detection of many biomolecular and chemical signals, etc.

#FIG. 1 is an example diagram illustrating a 3-D view of an optical device including multiple elements disposed on a host substrate according to embodiments herein.

#FIG. 2 is an example diagram illustrating a side view and functionality of an optical device according to embodiments herein.

#FIG. 3 is an example diagram illustrating a fabricator environment to fabricate the different types of optical devices as discussed herein.

#The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of preferred embodiments herein, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, with emphasis instead being placed upon illustrating the embodiments, principles, concepts, etc.

#This disclosure includes the observation that traditional optical materials such as glass and polymers become opaque in the mid-IR range. Embodiments herein include a unique material combination of first material such as nanocrystalline PbTe (n=5.0, such as geometries disposed on a substrate) and second material such as a CaF2 substrate (n=1.4), which offers a large refractive index contrast (such as greater than 2.5), such as broadband mid-IR transparency up to 9 microns, and compatibility with wafer-scale, high-throughput fabrication. With respect to device engineering and fabrication, embodiments herein provide an inherent trade-off between phase coverage and optical efficiency in conventional Huygens metasurface structures.

#Further embodiments herein include a novel two-component meta-atom design to overcome the above-mentioned limitations to achieve simultaneously full 360-degree phase coverage and near-unity optical transmission. Note that the optical devices as discussed herein can take any form such as diffractive beam deflectors, cylindrical lenses, aspheric lenses operating near the mid-IR band of 5.2 microns.