Spectral Domain Phase Microscopy Sub-Nanometer Resolution
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Solution Overview
Problem
Current optical coherence tomography (OCT) techniques have limited spatial resolution, unable to resolve structures smaller than 1-10 μm, which is insufficient for studying cellular surface profiles and dynamics on a nanometer scale, and existing non-invasive optical microscopy methods are invasive or limited in resolution.
Innovation Solution
The method involves obtaining multiple broadband interferometric optical profiles of a structure as a function of depth, selecting an axial position, determining phase variations, and identifying physical displacements based on these variations, enabling sub-coherence length resolution and sub-nanometer scale profiling using Spectral Domain Phase Microscopy (SDPM).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OCT techniques are used, then noninvasive imaging is achieved, but spatial resolution is limited to 1-10 μm
Solution Approach 1:
The patent changes the measurement parameter from intensity-based OCT to phase-based measurement. By extracting and analyzing phase information from interferometric signals, the system achieves sub-nanometer resolution, overcoming the 1-10 μm limitation of conventional OCT while maintaining noninvasive imaging capabilities.
2Measurement precision
If scanning probe microscopies (AFM, STM, SNOM) are used, then sub-50 nm resolution is achieved, but the techniques are invasive to surface structures
Solution Approach 1:
The patent replaces mechanical scanning probe techniques with optical interferometric measurement. By using light-based phase detection instead of physical probes, the system achieves sub-50 nm resolution without mechanical contact, thereby eliminating the invasive effects of AFM, STM, and SNOM on surface structures.
3Measurement precision
If optical microscopy techniques are used, then noninvasive imaging is achieved, but spatial resolution is limited to about 50 nm
Solution Approach 1:
The patent transitions from intensity-based optical microscopy to phase-based interferometric measurement. By measuring optical phase variations rather than light intensity, the system achieves sub-nanometer resolution, surpassing the 50 nm diffraction limit of conventional optical microscopy while maintaining noninvasive imaging.
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 approach provides sub-nanometer scale resolution and motion analysis, overcoming the resolution limitations of conventional OCT and invasive issues of other techniques, allowing for non-invasive, high-resolution imaging of cellular structures and dynamics.
Implementation Method 1
optical coherence tomography (OCT) has emerged as a promising imaging modality... based on the one-dimensional technique of optical coherence domain reflectometry (OCDR)... low-coherence interferometers that have been configured for characterization of the scattering properties
Implementation Method 2
The sample is placed in the sample arm of a Michelson interferometer, and a scanning optical delay line is located in the reference arm... depth in the sample is gated by low coherence interferometry
Implementation Method 3
SD-OCT uses a broadband light source and achieves spectral discrimination with a dispersive spectrometer in the detector arm
Implementation Method 4
SS-OCT time-encodes wavenumber by rapidly tuning a narrowband source through a broad optical bandwidth
Data Source
AI summary
Structure profiles from optical interferometric data can be identified by obtaining a plurality of broadband interferometric optical profiles of a structure as a function of structure depth in an axial direction. Each of the plurality of interferometric optical profiles include a reference signal propagated through a reference path and a sample signal reflected from a sample reflector in the axial direction. An axial position corresponding to at least a portion of the structure is selected. Phase variations of the plurality of interferometric optical profiles are determined at the selected axial position. A physical displacement of the structure is identified based on the phase variations at the selected axial position.