Terahertz Wave Lens Uneven Structure for Thin Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing terahertz wave lenses face challenges in minimizing size while avoiding aberration and complexity in production, particularly due to the use of SiO2 as an etching stopper layer, which absorbs terahertz waves, and the complexity of forming uneven structures using high-brightness processing lasers and interference masks.
Innovation Solution
A terahertz wave lens with a substrate featuring a periodic uneven structure composed of protruding or recessed portions with varying heights and widths, arranged in regions with constant spacing, allowing for phase difference modulation and reduced thickness, which suppresses aberration and simplifies design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If SiO2 is used as an etching stopper layer to achieve uniform etching depth, then the height of the uneven structure can be made uniform, but SiO2 absorbs light in the terahertz region making it unsuitable for terahertz wave optical elements
Solution Approach 1:
The patent removes the SiO2 etching stopper layer from the structure. Instead of using SiO2 as both etching stopper and surface layer, the invention extracts the stopper function to a separate sacrificial layer (such as a low-melting-point glass layer or organic resin layer) that is applied after the uneven structure formation, thereby eliminating terahertz absorption while maintaining etching uniformity control
Solution Approach 2:
The patent applies different materials for different functions: a material suitable for etching control is used during the etching process, while a material transparent to terahertz waves is used for the final surface layer. This local differentiation of material properties resolves the contradiction between etching precision and terahertz transparency
2Ease of manufacture
If high-brightness processing laser and interference mask are used to form uneven structure with spatially modulated height, then the uneven structure can be formed, but the process becomes complicated requiring multiple components
Solution Approach 1:
The patent replaces the complex optical system (high-brightness laser + interference mask) with a simpler photolithography approach using conventional photomasks and standard photolithography processes. The uneven structure is formed by patterning a resist layer and performing selective etching, substituting complex optical interference mechanisms with straightforward photochemical patterning
Solution Approach 2:
The patent changes the formation method parameters from laser-based interference patterning to photolithography-based patterning. By using conventional photomasks with designed patterns and standard etching conditions, the invention achieves spatially modulated uneven structures with simpler equipment and processes
3Manufacturing precision
If etching is stopped when etching stopper layer is exposed to achieve uniform height, then the height can be uniform, but the outer end portions become irregular causing aberration
Solution Approach 1:
The patent applies a sacrificial stopper layer (such as low-melting-point glass or organic resin) after the uneven structure is formed by etching. This preliminary application of a removable layer allows the etching to proceed uniformly while the stopper layer is subsequently removed to reveal clean, uniform outer end portions, preventing aberration
Solution Approach 2:
The patent uses a sacrificial stopper layer that is intentionally discarded after serving its purpose. The layer is applied to control etching depth, then removed entirely to leave clean surfaces without irregularities, effectively discarding the control mechanism after it has fulfilled its function
4Reliability
If a spherical lens is used to concentrate or collimate terahertz wave, then the lens can achieve the function, but the size of the lens becomes large
Solution Approach 1:
The patent creates an uneven structure with curved surfaces on the substrate to provide the necessary phase modulation for terahertz wave concentration or collimation. By forming periodic protrusions or recesses with carefully controlled curvature and depth, the invention achieves lens functionality in a flat, thin substrate, eliminating the need for bulky spherical lenses
Solution Approach 2:
The patent transitions from a three-dimensional spherical lens geometry to a two-dimensional periodic uneven structure on a flat substrate. By modulating the surface in the thickness direction with periodic features, the invention achieves optical focusing/collimation functionality while maintaining a thin, planar form factor
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The lens achieves reduced size, suppressed aberration, and simplified production by using microloading effects in etching to form regions with distinct refractive indices, facilitating phase distribution design and eliminating the need for additional reflection prevention layers.
Implementation Method 1
a surface provided with an uneven structure that changes a phase of the terahertz wave
Implementation Method 2
using microloading effects in etching to form regions with distinct refractive indices
Implementation Method 3
a terahertz wave lens that concentrates or collimates a terahertz wave... an uneven structure that changes a phase of the terahertz wave
Data Source
AI summary
A terahertz wave lens concentrates or collimates a terahertz wave. The terahertz wave lens includes a substrate having a surface provided with an uneven structure that changes a phase of the terahertz wave. The uneven structure includes a plurality of pillars that are periodically arranged. The uneven structure includes a plurality of regions where the plurality of pillars are arranged. A height of the pillar in a thickness direction of the substrate and a width of the pillar differ for each of the regions. A distance (period) between centers of the pillars adjacent to each other is constant. Outer end portions of the uneven structure in the thickness direction are located on the same plane.