Cylindrical Lens Interference Structuring for Ultrashort Laser Pulses
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Solution Overview
Problem
Existing optical devices for interference structuring of samples are costly, prone to misalignment, and unsuitable for ultra-short laser pulses due to large path differences between partial beams, which exceed the coherence length of laser radiation, making them inefficient and difficult to handle.
Innovation Solution
The optical device manipulates laser beams using cylindrical lenses in specific planes to maintain beam path alignment, allowing for precise control of interference patterns without altering the beam path in perpendicular planes, enabling interference structuring with short and ultra-short pulse durations by minimizing path differences and maintaining coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of optical elements are used to shape and deflect partial beams, then interference structuring can be achieved, but the device becomes expensive and prone to misalignment
Solution Approach 1:
The patent extracts and eliminates unnecessary optical elements from the interference structuring system. By using a beam splitter that directly divides the laser beam into partial beams without requiring additional shaping and deflection elements, the device reduces the number of optical components while maintaining the core interference structuring function.
Solution Approach 2:
The beam splitter serves multiple functions simultaneously: it divides the laser beam into partial beams, maintains the coherence length by keeping path differences small, and enables interference structuring without requiring separate optical elements for beam shaping and deflection. This multi-functionality reduces overall device complexity.
2Reliability
If the path length difference between partial beams is large, then complex beam manipulation is possible, but the coherence length is exceeded and interference cannot occur
Solution Approach 1:
The patent changes the critical parameter of path length difference by using a beam splitter configuration that keeps the optical path lengths of partial beams nearly equal. This parameter change ensures the path difference remains within the coherence length of the laser, enabling interference to occur even with ultrashort pulses, while still allowing sufficient beam manipulation for structuring.
3Manufacturing precision
If precise angles of deflection are maintained, then interference structuring accuracy is improved, but the device becomes more complicated and difficult to adjust
Solution Approach 1:
The beam splitter configuration inherently maintains the required angular relationships between partial beams through its geometric design. The system self-regulates the deflection angles based on the beam splitter's position and orientation, eliminating the need for complex adjustment mechanisms and making the device easier to operate while maintaining structuring accuracy.
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 approach simplifies handling, reduces costs, and allows for effective interference structuring with ultra-short laser pulses, making the device more efficient and suitable for a wide range of pulse durations, including femtosecond and picosecond pulses.
Implementation Method 1
The optical device comprises at least one first cylindrical lens, at least one second cylindrical lens, and at least one third cylindrical lens... manipulate the laser beam, including its partial beams, in a first plane that encompasses the optical axis and is arranged perpendicular to the cylinder axis of the at least one first cylindrical lens
Implementation Method 2
a laser beam is split into two partial beams which interfere with each other in a structural region of the sample by means of further optical components, the structuring of the sample being formed as a result of the spatial interferometric energy distribution of the interfering partial beams
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
The invention relates to an optical device, to the use thereof and to a method for the interference structuring of a sample. A laser emits a laser beam, which is split into at least two sub-beams by a beamsplitter. A first cylindrical lens and a second cylindrical lens for refracting the sub-beams into an interference region are arranged in the beam path. The sub-beams interfere in such a way that a structure having line-shaped structure elements can be formed in a structuring region of the sample. The cylinder axis of the first cylindrical lens is oriented parallel to the cylinder axis of the second cylindrical lens.