Re-injection Mirror for Off-Axis Cavity Spectroscopy Power
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Solution Overview
Problem
Off-axis optical cavity-based absorption spectroscopy techniques suffer from low light levels due to the lack of power build-up inside the cavity, limiting their applicability, especially with weak laser sources or non-laser sources.
Innovation Solution
The implementation of a re-injection mechanism where light initially failing to couple into the optical cavity is repeatedly reflected back and re-injected, utilizing a re-injection mirror to enhance coupling efficiency by multiple reflections, effectively multiplying the net optical power coupled into the cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If off-axis injection is used to disrupt optical resonances, then frequency selectivity is removed and broadband operation is achieved, but optical power build-up is eliminated and light levels become too low for practical applications
Solution Approach 1:
A re-injection mirror is introduced as an intermediary component to collect and redirect light that would otherwise be lost. This mirror acts as a mediator between the off-axis injection system and the optical cavity, enabling power recovery without compromising the broadband operation achieved through off-axis injection.
Solution Approach 2:
The patent recovers optical power that would normally be discarded or lost during off-axis injection. By using the re-injection mirror to capture and redirect light, the system recovers power that would otherwise be lost, transforming a harmful loss into a useful resource that enhances the overall light level in the cavity.
2Measurement precision
If high reflectivity mirrors are used to minimize intrinsic losses, then measurement sensitivity is improved, but the fraction of light failing to couple into the cavity increases, reducing the effective power injected
Solution Approach 1:
The re-injection mirror creates a feedback mechanism that redirects light failing to couple into the cavity back toward the cavity entrance. This feedback loop continuously attempts to couple light into the cavity, effectively compensating for the high reflectivity loss and improving overall coupling efficiency without sacrificing measurement sensitivity.
Solution Approach 2:
The system maintains continuous attempts to couple light into the cavity through multiple reflections involving the re-injection mirror. Rather than a single coupling event, the process continues until light successfully enters the cavity or is eventually transmitted, ensuring maximum utilization of the available optical power.
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 significantly increases the injected optical power, allowing for the use of weaker light sources and improving the signal-to-noise ratio, making the technique more practical and effective for various applications.
Implementation Method 1
The implementation of a re-injection mechanism where light initially failing to couple into the optical cavity is repeatedly reflected back and re-injected, utilizing a re-injection mirror to enhance coupling efficiency by multiple reflections
Implementation Method 2
high finesse optical cavities amplify optical loss processes occurring between the cavity optics
Implementation Method 3
These resonances, which are interferometric in nature, comprise the general subject of Fabry-Perot theory
Implementation Method 4
A photodetector measure total intra-cavity loss by observing the exponential decay over time of the output intensity following the radiation injection
Implementation Method 5
Light trapped in the optical cavity passes through the absorbing sample many times, so the observed amplification of the absorption signal is very large
Data Source
AI summary
An absorption spectroscopy instrument is provided with a re-injection mirror to greatly increase the optical power coupled into an optical cavity, comprised of two or more mirrors, for the purpose of increasing the quality of absorption and extinction measurements made in the cavity. Light reflected from the first cavity mirror upon which a light beam is incident, can be efficiently collected and back reflected onto the same mirror, effectively producing a plurality of optical injections into the cavity. The instrument can be used for off-axis cavity ringdown spectroscopy, off-axis integrated cavity output spectroscopy, or other cavity-based spectroscopy applications.