Pellicle Beam Splitter Fabrication via Thin Film Substrates
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Solution Overview
Problem
Conventional beam splitters with thick substrates suffer from stray reflections, ghosting, beam offsets, and optical interference due to their thickness, which leads to undesirable optical characteristics such as higher losses and misalignment issues.
Innovation Solution
The use of pellicle beam splitters with thin substrates, such as stretched organic materials or nitride membranes, where beam-splitting coatings are deposited, minimizing these issues by reducing substrate thickness and enhancing mechanical stability through semiconductor fabrication techniques like low-pressure chemical vapor deposition and lithographic processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick substrate is used for beam splitters, then mechanical stability is improved, but optical losses increase and beam offsets occur
Solution Approach 1:
The patent applies this principle by using thin substrate materials (such as stretched organic materials or nitride membranes) instead of thick substrates. These thin films provide sufficient mechanical stability while minimizing optical path differences and reducing optical losses, thereby resolving the contradiction between mechanical strength and optical performance.
Solution Approach 2:
The patent changes the thickness parameter of the substrate from conventional thick dimensions to thin dimensions (pellicle thickness). This parameter change reduces the optical path length through the substrate, minimizing beam offsets and optical interference while maintaining adequate mechanical stability through proper material selection and tension control.
2Stability of the object's composition
If a thick substrate is used for beam splitters, then structural integrity is maintained, but ghosting and optical interference increase
Solution Approach 1:
By transitioning from thick rigid substrates to thin flexible films (pellicles), the patent eliminates multiple internal reflection surfaces that cause ghosting and optical interference. The thin film structure maintains structural integrity through tension and proper material properties while eliminating the harmful optical effects associated with thick substrates.
Solution Approach 2:
The patent extracts the beam-splitting functionality from the thick substrate context and relocates it to a thin pellicle membrane. This extraction removes the source of ghosting and optical interference (the thick substrate interfaces) while preserving the essential beam-splitting function through coatings applied on the thin membrane.
3Ease of manufacture
If conventional beam splitter configurations are used, then manufacturing simplicity is maintained, but alignment precision deteriorates
Solution Approach 1:
The thin pellicle construction simplifies alignment procedures compared to thick beam splitters. The reduced thickness minimizes beam offsets and makes the beam splitter easier to position and align in optical systems, thereby improving alignment precision while maintaining ease of manufacture through established thin-film deposition techniques.
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
Pellicle beam splitters reduce optical losses and beam offsets, improving alignment and reducing ghosting, while maintaining mechanical stability and temperature stability suitable for various photonics applications.
Implementation Method 1
Beam splitters use a partially reflective surface to reflect a portion of incident light while allowing the remainder to be transmitted through the beam splitter
Implementation Method 2
enhancing mechanical stability through semiconductor fabrication techniques like low-pressure chemical vapor deposition
Data Source
AI summary
A method for fabricating a pellicle beam splitter includes etching an aperture in a support substrate; bonding a beam splitter substrate to an upper surface of the support substrate so that the beam splitter substrate covers the aperture; and depositing at least one optical coating on the beam splitter substrate. A pellicle beam splitter includes a support substrate, an aperture created in the support substrate using a semiconductor fabrication processes and a beam-splitting coating covering the aperture.