Self-imaging interferometer for high-contrast gas jet imaging
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Solution Overview
Problem
Current methods for characterizing gas targets, particularly low-density gas jets, face challenges in achieving high-contrast imaging due to low signal-to-noise ratios and loss of spatial information, as existing interferometry techniques either require multiple passes through the medium or result in low sensitivity.
Innovation Solution
A device and method utilizing a beam splitter to split an incident beam into a probe and reference beam, with the probe interacting with the object at least twice through a self-imaging system, allowing for high-contrast imaging while preserving spatial information and increasing sensitivity by multiple interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Michelson interferometer is used with two passes through the medium, then the sensitivity of measurement is improved, but spatial distribution information is lost
Solution Approach 1:
The probe beam path is segmented into multiple sequential interactions with the object. The beam passes through the object multiple times in a folded configuration, with each pass contributing to the cumulative phase shift measurement while maintaining spatial resolution through proper beam routing and imaging optics.
Solution Approach 2:
Multiple beam passes are nested within a single interferometric measurement configuration. The beam traverses the object repeatedly through a folded optical path, with each traversal nested within the same interference pattern measurement, accumulating sensitivity while preserving spatial information through coherent addition of phase shifts.
2Loss of information
If a Mach-Zehnder interferometer is used for imaging, then spatial distribution information is preserved, but measurement sensitivity is reduced
Solution Approach 1:
The optical path is made dynamic through multiple reversible traversals of the object. The beam folds back through the same region multiple times, with the direction of propagation changing dynamically while maintaining the same spatial sampling points, thereby accumulating phase information without losing spatial resolution.
Solution Approach 2:
The probe beam continuously interacts with the object through multiple sequential passes rather than a single traversal. Each pass contributes additively to the measured phase shift, maintaining continuous useful action on the same spatial region and thereby improving sensitivity while preserving spatial distribution information.
3Ease of manufacture
If absorption method is used to assess gas density, then the method is simple to implement, but the signal-to-noise ratio is low for low-density gases
Solution Approach 1:
The probe beam performs periodic traversals through the gas medium in a folded optical path, with each traversal contributing to the cumulative absorption signal. This periodic interaction through multiple passes amplifies the weak absorption signal from low-density gas while maintaining the simplicity of absorption-based detection.
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
Enhances the sensitivity and contrast of optical probing, maintaining spatial resolution and improving the ability to characterize gas density distributions and other optical properties with increased signal-to-noise ratios.
Implementation Method 1
a beam splitter which splits an incident beam to a probe beam and a reference beam
Implementation Method 2
a self-imaging system receiving the probe beam from the object which is capable to image the object on itself, preferably while preserving the beam divergence
Implementation Method 3
the probe beam interacts with the object at least twice. A first interaction is provided when the probe beam is propagating from the splitter to the self-imaging system. The second interaction is provided when the beam is reflected from the self-imaging system to the beam splitter
Data Source
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AI summary
The present invention relates to a device, use of the device and a method for high contrast imaging, particularly suitable for imaging of moving object of interest such as gas expanding from a gas jet or physical or chemical or biological processes in material. The device for high-contrast imaging comprises a beam splitter (21) for splitting a beam (1) into a probe beam (3) and a reference beam (7), wherein the probe beam (3) is directed to an object (6); a self-imaging system (30) for receiving the probe beam (3) from the object (6) and imaging the object (6) on itself while in a preferred embodiment, the system (30) preserves the a reflected probe beam (31) divergence. The beam (3, 31) interacts with the object (6) at least twice; and the reflected probe beam (31) is further directed to the splitter (21) after the last interaction; and detection means (11) receiving the probe beam (31) from the splitter (21).