DLIP Optical Arrangement With Equal Path Length Beam Splitting
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Solution Overview
Problem
Current optical arrangements for direct laser interference patterning are not cost-effective, lack flexibility in adapting to different wavelengths and interference periods, and suffer from significant power losses and alignment issues, particularly when using ultrashort pulse lasers.
Innovation Solution
An optical arrangement featuring a reflecting element oriented at 45°, a first beam splitter, and optional pentamirrors or pentaprisms to split and direct laser beams with equal path lengths, allowing for adjustable interference periods and flexible beam orientation, along with a focusing lens and waveplates for polarization control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beam splitters, prisms or diffractive optical elements are used to split the laser beam, then the beam can be divided into partial beams, but significant power losses occur and alignment issues arise
Solution Approach 1:
The patent uses a diffractive optical element to create multiple virtual copies of the beam path through diffraction, allowing the laser beam to be split into multiple partial beams without physical beam splitters. This copying approach eliminates the power losses and alignment issues associated with traditional beam splitting components while maintaining high beam splitting efficiency
2Adaptability or versatility
If conventional optical arrangements are used for direct laser interference patterning, then beam splitting can be achieved, but the arrangements are expensive and lack flexibility in adapting to different wavelengths and interference periods
Solution Approach 1:
The diffractive optical element is designed to be wavelength-independent and can generate interference patterns with different periods by adjusting the diffraction order. This single element performs multiple functions (beam splitting, path length adjustment, interference pattern generation) that would otherwise require multiple specialized components, reducing both cost and complexity while increasing adaptability
Solution Approach 2:
The interference period can be changed by adjusting parameters such as the diffraction angle or the position of the focusing lens, rather than changing the entire optical arrangement. This parameter-based control provides flexibility in adapting to different patterning requirements without increasing device complexity
3Manufacturing precision
If ultrashort pulse laser sources are used, then high resolution patterning can be achieved, but the distances traveled by individual partial beams must not differ significantly
Solution Approach 1:
The diffractive optical element acts as an intermediary that creates symmetric diffraction orders with equal path lengths from the source to the interference zone. This intermediary structure inherently balances the optical paths for all partial beams, eliminating the need for complex active path length adjustment mechanisms while maintaining the high resolution patterning capability of ultrashort pulse lasers
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
This arrangement enables simple, cost-effective, and flexible direct laser interference patterning across various wavelengths with minimal power losses, allowing for precise control of interference patterns and adaptable to different laser pulse lengths.
Implementation Method 1
a laser beam emitted from a laser radiation source is directed to an element which reflects the laser beam and the reflective surface of which is oriented at an angle of 45° in relation to the optical axis of the laser beam
Implementation Method 2
The laser beam reflected by the reflecting element is incident on a first beam splitter, which splits the reflected laser beam into two partial beams
Implementation Method 3
the partial beams oriented with their optical axes parallel to one another are directed to said surface by the focusing optical element, preferably a lens, in a manner interfering with one another
Implementation Method 4
direct laser interference patterning (DLIP), by which a patterning can be formed on surfaces of workpieces or components
Data Source
AI summary
An optical arrangement for direct laser interference structuring. A laser beam is directed to a reflecting mirror with inclined surface and strikes a first beam splitter, it is divided into two partial beams and one partial beam is deflected to a focusing element. The second partial laser beam is directed to a first pentamirror and after multiple reflection and/or refraction, the focusing element, or it is directed to a second beam splitter and is divided into a first partial beam and a third partial beam. The partial beams are directed to the focusing element by the first pentamirror and are directed by the focusing element to the surface to be structured interfering with each other. The reflecting mirror is moved in a translational manner, maintaining a 45° angle parallel to the optical axes of the emitted laser beam influencing the interference period Λ.