Multi-pass Cell Perturbing Mirror Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-pass cells for long path-length spectrometers face challenges such as high production costs due to complex mirror surfaces, low optical throughput, inefficient use of volume, and limited adjustability of reflection numbers.
Innovation Solution
An improved multi-pass cell design featuring a perturbing mirror that repeats and rotates a base reflection pattern, allowing for adjustable pattern multiplication factors and efficient use of mirror surfaces, constructed with spherical mirrors for economic production and high optical throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex mirror surfaces are used to achieve specific reflection patterns, then the desired reflection pattern is obtained, but production costs increase
Solution Approach 1:
The complex reflection pattern is segmented into a base pattern and a perturbation pattern. The base pattern uses simple spherical mirrors, while the perturbation is achieved by adding a separate perturbing mirror that introduces rotational displacement. This segmentation allows each component to be manufactured independently with simpler requirements.
Solution Approach 2:
The patent combines a simple base reflection pattern with an additional perturbing mirror to achieve the complex desired pattern. Instead of manufacturing one complex mirror, the system merges a simple spherical mirror (for base pattern) with a perturbing mirror (for pattern rotation), achieving the same effect through combination of simpler components.
2Reliability
If traditional multi-pass cell designs are used, then basic reflection patterns are achieved, but optical throughput is reduced
Solution Approach 1:
The patent introduces dynamic adjustability to the reflection pattern by using a perturbing mirror that can be rotated or repositioned. This allows the pattern multiplication factor and rotation angle to be dynamically changed without redesigning the entire cell, optimizing optical throughput for different measurement requirements while maintaining manageable device complexity.
Solution Approach 2:
The system changes key parameters (pattern multiplication factor, rotation angle, number of passes) by adjusting the position or orientation of the perturbing mirror rather than changing the fundamental cell structure. This allows optimization of optical throughput through parameter adjustment while keeping the base cell design relatively simple.
3Volume of stationary object
If fixed reflection patterns are used, then cell volume is underutilized, but device simplicity is maintained
Solution Approach 1:
The patent adds a rotational dimension to the base reflection pattern. The perturbing mirror introduces a rotation angle that causes the beam to trace multiple rotated copies of the base pattern, effectively filling the cell volume in a three-dimensional pattern rather than a simple two-dimensional path, thereby utilizing cell volume more efficiently.
Solution Approach 2:
The system provides dynamic control over pattern multiplication and rotation, allowing the reflection pattern to adapt and fill the cell volume more efficiently. By adjusting the perturbing mirror's position or angle, the beam path can be optimized to utilize the available cell volume for different numbers of passes and pattern repetitions.
4Manufacturing precision
If complex mirror surfaces are used to adjust reflection numbers, then precise control is achieved, but ease of operation is reduced
Solution Approach 1:
The control of reflection number is segmented into two independent functions: the base spherical mirror provides stable, fixed-pattern reflections, while the perturbing mirror provides adjustable pattern multiplication and rotation. This segmentation allows independent optimization - the base mirror for precision and the perturbing mirror for ease of adjustment.
Solution Approach 2:
Instead of changing the physical shape of complex mirrors to adjust reflection numbers, the system changes operational parameters (number of passes, pattern multiplication factor, rotation angle) by simply repositioning or reorienting the perturbing mirror. This makes adjustment easier while maintaining precise control over the reflection pattern.
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 design enhances optical throughput, efficiently fills the cell's volume, and allows for easy adjustment of the number of reflections, improving the performance and cost-effectiveness of long path-length spectrometers.
Implementation Method 1
A beam 360 from a light source (e.g., a laser) (not shown) is directed onto a back mirror half 140, and repeatedly reflected between the back mirror 120 and the front mirror 110 according to a known pattern (the 'White cell pattern'), before eventually exiting the White cell 100.
Implementation Method 2
The mirrors may serve to repeatedly refocus the beam to keep it from spreading indefinitely.
Data Source
AI summary
In one embodiment, an improved multi-pass cell for a long path-length spectrometer is designed to include a perturbing mirror that causes a base pattern of reflections to be repeated multiple times, where each subsequent base pattern of reflections is rotated about the axis at an angle from a prior base pattern, to circulate the base patters about the cell. The base pattern may be a Herriott cell pattern. The improved multi-pass cell may be constructed with a concave front mirror centered along an axis of the cell, and a concave back mirror centered along the axis and facing the front mirror. The perturbing mirror may be centered along the axis, facing the front mirror and located at a perturbing mirror spacing in front of the back mirror or behind the back mirror, depending on the implementation.