Diffractive Element Phase Design for Stable Beam Diameter
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Solution Overview
Problem
Existing methods for designing diffractive elements fail to maintain the diameter of the bright spot on the imaging plane at a desired length in the optical axis direction, leading to reduced accuracy in laser processing and rust removal.
Innovation Solution
A method for designing a diffractive element that involves calculating electric field distributions using Gaussian and Bessel Gaussian beams, and determining the unevenness depth based on Kirchhoff's diffractive integral to maintain beam diameter and power within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional diffractive element design methods are used, then the design process is simple, but the beam diameter cannot be maintained at a desired length in the optical axis direction
Solution Approach 1:
The patent applies preliminary action by pre-calculating the electric field distribution on the emission plane and determining the optimal unevenness depth distribution before manufacturing. This advance planning ensures the beam diameter is maintained at the desired length without requiring complex real-time adjustments during operation.
Solution Approach 2:
The patent changes parameters by optimizing the unevenness depth distribution on the diffractive element surface based on calculated electric field distributions. By adjusting the depth parameter according to the phase distribution requirements, the system achieves precise beam diameter control over a extended range in the optical axis direction.
2Adaptability or versatility
If the focal point deviates in the optical axis direction, then the beam diameter cannot be held, but adjusting the focal position is necessary for processing objects at different depths
Solution Approach 1:
The patent transitions from one-dimensional focal point control to two-dimensional control by optimizing the phase distribution across the entire emission plane. This dimensional expansion allows the system to maintain beam quality both at the focal point and over an extended range along the optical axis, providing adaptability for different processing depths while preserving precision.
Solution Approach 2:
The patent introduces dynamics by designing the diffractive element to dynamically adapt to different focal positions through its optimized unevenness depth distribution. The element can effectively focus light at multiple depths along the optical axis, enabling versatile processing while maintaining beam diameter control through its engineered phase modulation profile.
3Measurement precision
If conventional design methods are used, then computational requirements are low, but laser processing accuracy is reduced
Solution Approach 1:
The patent replaces manual or simplified design methods with computer-based electromagnetic field calculations. By substituting computational methods for conventional design approaches, the system achieves higher laser processing accuracy through precise electric field distribution analysis and optimization of the diffractive element parameters.
Solution Approach 2:
The patent creates a computational model (copy) of the electromagnetic field distribution to predict and optimize the diffractive element performance before manufacturing. This virtual copying and simulation approach enables high-precision laser processing by allowing detailed analysis and optimization without requiring physical prototypes or trial-and-error manufacturing.
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 designed diffractive element maintains beam diameter and power over a specified length, enabling precise laser processing and rust removal with enhanced accuracy and safety.
Implementation Method 1
a diffractive element (DOE, hereinafter referred to as a 'diffractive element' or 'DOE')... a kinoform is a diffractive element that only modulates the light phase... Light incident on the diffractive element 30 is emitted from an emission surface P0 of the diffractive element
Implementation Method 2
a kinoform is a diffractive element that only modulates the light phase and does not change the light intensity... an unevenness structure on the surface of the substrate
Data Source
AI summary
An embodiment is a method including calculating an electric field distribution of an emission light on an emission plane of the diffractive element with respect to the incident light, the incident light being a Gaussian beam, calculating an electric field distribution obtained by multiplying an electric field distribution of emission light from the emission plane by a Gaussian window in a plane parallel to the emission plane located at a predetermined distance from the emission plane, as an electric field distribution of a beam approximated by a Bessel Gaussian beam, calculating a first electric field distribution as an electric field distribution on the emission plane of the diffractive element with respect to the electric field distribution of the emission light on the plane, and determining a depth of an unevenness on a surface of the diffractive element.