Dual-Beam Self-Interfering Optical System for Fine Feature Detection
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Solution Overview
Problem
Conventional Michelson and Mirau interferometers are limited in detecting fine features on sample surfaces due to the use of a single light beam, resulting in reduced incident light intensity and complexity, especially for non-transparent specimens, which can lead to loss of depth and thickness information.
Innovation Solution
A self-interfering optical system with dual beams of equal path length, using a collimated light source, beam splitter, mirrors, and lenses to generate and combine interfered light beams without a reference path, allowing for oblique incidence and potential use of a Dove prism for image contrast enhancement and low-coherence light sources for optical coherence tomography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single light beam is used to probe the specimen in conventional interferometers, then the system structure is simpler, but the incident light intensity on the sample surface is reduced, limiting the capability of detecting fine features
Solution Approach 1:
The single light beam is segmented into two separate light beams that both illuminate the sample surface simultaneously. This segmentation allows doubling the incident light intensity while maintaining manageable system complexity through modular optical components
Solution Approach 2:
Two separate light beams are merged/combined to simultaneously illuminate the sample surface. The beam splitter divides the source beam into two paths, and after reflection from the sample, the beams are recombined at the beam splitter to generate interference patterns, effectively doubling the light intensity on the sample
2Reliability
If a reference path is incorporated in Michelson interferometer, then interference can be generated, but the system complexity increases and the reference path becomes critical to system operation
Solution Approach 1:
The reference path is extracted/removed from the traditional interferometer configuration. Instead of using a separate reference beam, the invention uses the sample's own reflected light as the reference, eliminating the need for additional reference path components and reducing system complexity while maintaining interference capability
Solution Approach 2:
The sample itself serves as the reference by providing the reference reflection. The light reflected from the sample surface acts as both the measurement beam and the reference beam, allowing the system to be self-sufficient without external reference paths
3Measurement precision
If back scattered light is used for interference in non-transparent specimens with Mirau interferometer, then interference results can be obtained, but optical intensity illuminated on the specimen is further reduced and depth/thickness information is lost
Solution Approach 1:
The light beam is segmented into two separate beams that both illuminate the sample, ensuring sufficient light intensity while enabling precise measurement of depth and thickness information through interference of the reflected beams
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 configuration increases incident light intensity on the sample, enhances image contrast, and provides stable, high-resolution images without the complexity of reference paths, enabling the detection of fine features and depth information with improved sensitivity and stability.
Implementation Method 1
a beam splitter for dividing the initial light beam into two comparable light beams
Implementation Method 2
two mirrors and two lens, a focus lens... receives two reflected light beams from the sample
Implementation Method 3
two mirrors and two lens, a focus lens... directs the two light beams and focus them onto a surface of the sample
Implementation Method 4
receives two reflected light beams from the sample back to the beam splitter
Implementation Method 5
generating an interfered light beam by combining the two reflected light beams at the beam splitter
Data Source
AI summary
An optical system includes a collimated light source, a beam splitter, two mirrors and two lenses, a focus lens, and a detector. An initial light beam is generated by the light source and then separated by the beam splitter into a first light beam and a second light beam. The two mirrors respectively direct the first and second light beams on a sample with symmetrical paths and the two lenses focus the first and second light beam on the sample respectively. The first and second light beams are reflected from the sample and along the counterpart paths to the beam splitter. An interfered light beam is then generated by combining the reflected first and second light beams, and focused by a focus lens on a detector. A Dove prism can be configured between one mirror and one lens of the two for contrast enhancement. It can produce the photon combination with same of direction in this setup to enhance contrast.