Structured Beam Generation Using Convex Lens Aberrations
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Solution Overview
Problem
Existing systems for generating structured beams suffer from limited range and quality issues, resulting in increased divergence and reduced precision over long distances, making them unsuitable for high-precision measurement technologies and requiring complex optical setups that are difficult to adjust.
Innovation Solution
An optical system comprising a convex lens with a refractive index of at least 1.8 and a focusing element, which produces a structured beam by illuminating the lens with a coherent beam to create aberrations, allowing the beam to maintain low divergence and a well-defined intensity distribution over large distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional Gaussian beams are used, then the beam can be generated with simple optics, but the beam diverges and increases in size over distance, reducing precision
Solution Approach 1:
The patent changes the fundamental parameter of beam intensity distribution from Gaussian to structured (Bessel/Airy) patterns by using specific optical elements (axicons, zonal plates, or computer-generated holograms). This parameter change enables the beam to maintain a fixed radial intensity distribution over long distances while using relatively simple optical components, thereby resolving the contradiction between system simplicity and measurement precision.
2Measurement precision
If a beam expander and collimator are used to decrease divergence, then the beam divergence is reduced, but the beam becomes larger and measurements of high precision become difficult
Solution Approach 1:
The patent employs structured beam generation techniques that fundamentally change the beam's intensity distribution parameter from Gaussian to Bessel/Airy patterns. This allows the beam to maintain both small spot size and low divergence simultaneously, as the structured intensity distribution inherently resists diffraction-induced spreading, eliminating the need for beam expanders that would increase the beam area.
3Shape
If known systems use axicon lenses to generate structured beams, then the beam structure is created, but the beam quality degrades over distance beyond one meter
Solution Approach 1:
The patent introduces intermediate optical elements (zonal plates or computer-generated holograms) that act as mediators between the light source and the final beam structure. These intermediaries enable the generation of high-quality structured beams with well-defined intensity distributions that maintain their shape over extended distances beyond one meter, overcoming the limitation of axicon-only systems.
4Measurement precision
If complex optical systems with multiple components are used to generate structured beams, then the beam quality is improved, but the system becomes difficult to adjust and align
Solution Approach 1:
The patent extracts and emphasizes the use of computer-generated holograms as a standalone or primary optical element that can generate structured beams with high quality. This approach reduces the need for complex assemblies of multiple optical components, thereby improving ease of operation and alignment while maintaining beam quality through the holographic method.
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 system generates a high-quality structured beam with reduced divergence and a well-defined intensity distribution, enabling precise measurements over long distances with a simpler and more adjustable setup compared to existing systems.
Implementation Method 1
a convex lens having a spherical or cylindrical entry surface, the convex lens comprising a material having a refractive index of at least 1.8
Implementation Method 2
a focusing element arranged along the optical axis of the optical system
Data Source
AI summary
An optical system for producing a structured optical beam including a convex lens having a spherical or cylindrical entry surface, an electromagnetic radiation source configured to provide a substantially coherent beam of electromagnetic radiation, and a focusing element arranged along the optical axis of the optical system. The electromagnetic radiation source is arranged to produce an illuminating beam which illuminates the convex lens over a selected illumination fraction of the spherical or cylindrical entry surface and with a corresponding selected focus of the illuminating beam such that the beam traverses a sufficient refractive volume of the convex lens to produce aberrations in the beam emerging from the convex lens such that it comprises a structured optical beam. The system and method allows for generating a structured beam which can propagate over the large distances while maintaining a well-defined cross-section intensity distribution.