Displaced Sagnac Interferometer for Phase-Resolved Spectroscopy
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Solution Overview
Problem
Existing phase-resolved spectroscopy techniques face challenges in generating precise time delays between local oscillator (LO) and signal light pulses in collinear geometry, often requiring complex active phase stabilization or dispersive materials that limit wavelength flexibility and stability.
Innovation Solution
A method using a displaced Sagnac interferometer to create a local oscillator light beam by superimposing aligned measuring light beams in a nonlinear medium, allowing for collinear geometry without the need for dispersive materials or complex stabilization, ensuring high phase stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-collinear beams are used to generate LO and signal light, then time delay can be achieved using dispersive medium, but sample position must be maintained with accuracy up to 100 nm which is technologically challenging
Solution Approach 1:
The patent employs non-collinear beam geometry where the LO and signal beams propagate at different angles, creating an asymmetric configuration that enables time delay through spatial separation rather than requiring precise sample position control. This asymmetric arrangement allows the dispersive medium to act on one beam path independently, achieving temporal delay without coupling the measurement to sample position stability.
Solution Approach 2:
The patent introduces a dispersive medium as an intermediary element placed in the LO beam path to generate the required time delay. This intermediary component mediates the temporal relationship between LO and signal beams by exploiting dispersion effects, thereby achieving precise time delay control without directly affecting the sample position requirements.
2Ease of operation
If collinear beams are used to generate LO and signal light, then sample position independence is achieved, but generating few to several picosecond time delay between LO and signal light is challenging
Solution Approach 1:
The patent transitions from a temporal delay generation problem in collinear geometry to a spatial-temporal solution by using non-collinear beam propagation. By introducing angular separation (another dimension), the system can achieve time delay through the combination of spatial separation and dispersive effects, rather than relying solely on temporal manipulation in a single dimension.
Solution Approach 2:
The patent changes the propagation parameters of the beams by using non-collinear geometry, which fundamentally alters how time delay can be achieved. Instead of trying to generate picosecond delays through temporal modulation in collinear beams, the system exploits the relationship between spatial angle and temporal delay through dispersion, changing the fundamental parameter space in which delay is controlled.
3Measurement precision
If Michelson-type interferometer is used to produce time delay in collinear geometry, then time delay can be generated, but active phase stabilization is required which significantly complicates experimental setup
Solution Approach 1:
The patent extracts the phase stabilization requirement from the system by avoiding Michelson-type interferometer geometry. By using non-collinear beam generation with dispersive delay, the system eliminates the need for active phase stabilization mechanisms, taking out the complex feedback and control systems that would otherwise be required to maintain interferometric stability.
Solution Approach 2:
The patent replaces expensive and complex active phase stabilization systems with a simpler, passive dispersive delay mechanism. The non-collinear beam configuration with dispersive medium provides inherent delay without requiring costly piezoelectric actuators, feedback loops, or active control electronics, effectively substituting a simple optical arrangement for a complex stabilization system.
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 precise time delay and phase stability for phase-resolved spectroscopy, enhancing data quality and reducing setup complexity across a broad wavelength range.
Implementation Method 1
creating the local oscillator light beam by an optical non-linear interaction of a first portion of the first measuring light beam and a first portion of the second measuring light beam in an optical nonlinear medium
Implementation Method 2
superimposing the local oscillator light beam, a second portion of the first measuring light beam and a second portion of the second measuring light beam with a predetermined mutual phase relationship
Implementation Method 3
superimposing the local oscillator light beam, a second portion of the first measuring light beam and a second portion of the second measuring light beam with a displaced Sagnac interferometer
Data Source
Figure 1~2
Figure 3A~3B
AI summary
A method of creating a local oscillator light beam LO for a phase- resolved spectroscopy measurement comprises the steps of providing a first measuring light beam (1) and a second measuring light beam (2) being aligned to each other, creating the local oscillator light beam LO by an optical non-linear interaction of a first portion (1A) of the first measuring light beam (1) and a first portion (2A) of the second measuring light beam (2) in an optical nonlinear medium (20), and superimposing the local oscillator light beam LO, a second portion (1B) of the first measuring light beam (1) and a second portion (2B) of the second measuring light beam (2) with a predetermined mutual phase relationship, for providing a sample light beam (3) for the phase-resolved spectroscopy measurement. The local oscillator light beam LO and the second portions (1B, 2B) of the first and second measuring light beams (1, 2) are superimposed with a displaced Sagnac interferometer (10).