Broadband Illumination Tuning With Angular-Scanning Filters
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Solution Overview
Problem
Tunable light sources suffer from limited capacity to quickly and precisely modify the intensity or spectrum of a tuned illumination beam, and external tunable filters have slow tuning speeds, limited spectral bandwidth, or limited polarization requirements.
Innovation Solution
A tunable filter system utilizing linearly-varying filters and scanning optics, including focusing optics and angular scanning components, allows for rapid and flexible tuning of broadband illumination sources by controlling the position of the input beam on the linearly-varying filter through angular scanning components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If typical external tunable filters are used, then filtering function is provided, but tuning speed is slow
Solution Approach 1:
The patent employs dynamic scanning optics (angular scanning components) that can rapidly change the angle of incident light on the linearly-varying filter, enabling fast tuning across the spectral bandwidth without mechanical movement of the filter itself. This dynamic angular scanning approach achieves tuning speeds significantly faster than conventional tunable filters.
2Adaptability or versatility
If typical tunable light sources are used, then illumination is provided, but capacity to quickly modify intensity or spectrum is limited
Solution Approach 1:
The patent uses a linearly-varying filter where different spatial positions on the filter correspond to different spectral filtering characteristics. By scanning the input beam to different positions on the filter through angular scanning, the system can rapidly select different spectral portions of the broadband illumination, achieving both versatility and speed.
3Area of stationary object
If typical tunable filters are used, then spectral selection is achieved, but spectral bandwidth is limited
Solution Approach 1:
Instead of using a conventional filter that selects wavelength along a single dimension, the patent introduces a spatial dimension by using a linearly-varying filter where wavelength selection is coupled with spatial position. The angular scanning component adds another dimensional control, allowing rapid access to different spectral regions across a broad bandwidth by changing the angle of incidence.
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
Enables rapid and precise tuning of illumination properties such as intensity, spectrum, and polarization, enhancing the flexibility and speed of tunable filters, and reduces speckle through angular scanning, facilitating faster measurement times and improved throughput.
Implementation Method 1
an input focusing optic to receive the input beam from the input angular scanning component and direct the input beam to the linearly-varying filter
Implementation Method 2
a linearly-varying filter, where filtering parameters of the linearly-varying filter differ based on spatial position on the linearly-varying filter
Implementation Method 3
an output focusing optic, where the output focusing optic receives the input beam from the linearly-varying filter as a filtered beam and directs the filtered beam to the output angular scanning component
Implementation Method 4
an output angular scanning component located at a back focal plane of the output focusing optic, where the output focusing optic receives the input beam from the linearly-varying filter as a filtered beam and directs the filtered beam to the output angular scanning component. In another illustrative embodiment, the output angular scanning component provides the filtered beam as an output beam along an output path selectable based on an angle of the output angular scanning component
Data Source
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Figure 1C
AI summary
A tunable filter may include an input focusing optic, an output focusing optic, a linearly-varying filter located at a back focal plane of the input focusing optic and a front focal plane of the output focusing optic, an input angular scanning component located at a front focal plane of the input focusing optic configured to receive an input beam, and an output angular scanning component located at a back focal plane of the output focusing optic. The input focusing optic may receive the input beam from the input angular scanning component and direct the input beam to the linearly-varying filter, where a position of the input beam on the linearly-varying filter is selectable based on an angle of the input angular scanning component. The output focusing optic may receive a filtered beam from the linearly-varying filter and direct the filtered beam to the output angular scanning component.