Downhole Laser Output Control for Compact Plasma Light Collection
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Solution Overview
Problem
Current laser-induced breakdown spectroscopy systems face challenges in controlling output pulse energy, are sensitive to temperature and pressure fluctuations, and have inefficient light collection due to the shape and divergence of the laser spark, leading to reduced analysis capabilities in extreme environments like downhole drilling.
Innovation Solution
The system incorporates an adjustable focus lens arrangement, a beam expander, and spectral emission control to manage beam size and energy, producing a more compact and symmetric plasma spark, reducing energy requirements and enhancing light collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a small diameter laser beam is focused into the water to produce a spark, then the laser energy is concentrated, but the spark becomes very long and filamentary, limiting the usable light for analysis to only the backward facing cross section
Solution Approach 1:
The patent transforms the symmetric small-diameter beam into an asymmetric expanded beam profile. By expanding the beam diameter before focusing, the system creates a broader, more uniform illumination area that produces a compact plasma spark rather than a long filamentary one, enabling better light collection from all directions including the previously hidden downstream portion
Solution Approach 2:
The patent adds the dimension of beam expansion in the transverse plane before focusing. Instead of simply focusing a small beam in one dimension, the system first expands the beam in the lateral dimensions and then focuses it, creating a different spatial distribution of energy that produces a more isotropic plasma spark suitable for confocal collection
2Device complexity
If the emitted light is transmitted a short distance back up the fiber that delivers the pump energy, then the system uses a single fiber for both pump and signal, but the light divergence prevents collecting all the emitted light into the original fiber
Solution Approach 1:
The patent introduces asymmetric optical elements (cylindrical lenses, prisms) that reshape the divergent light into a more directional beam. This asymmetric transformation of the light propagation pattern enables efficient coupling back into the circular fiber core despite the distance, maintaining the single-fiber advantage while overcoming the collection efficiency problem
Solution Approach 2:
The patent introduces intermediate optical components (lenses, prisms, beam shaping elements) between the plasma spark and the fiber input. These intermediaries act as mediators that capture the divergent light and redirect it into the fiber, enabling efficient light transmission back through the same fiber that delivers the pump energy
3Ease of manufacture
If DPSS solid state passively Q-switched systems are designed for one input and output level, then the system is simple to manufacture, but the ability to control the output pulse energy is limited
Solution Approach 1:
The patent introduces dynamic control mechanisms (variable attenuators, adjustable beam expanders, controllable focusing lenses) that allow the system to adapt its output characteristics in real-time. These dynamic elements enable continuous adjustment of pulse energy and beam parameters while maintaining the simplicity of the core DPSS laser design
Solution Approach 2:
The patent employs parameter change mechanisms that allow adjustment of key optical parameters (beam diameter, focus position, energy attenuation) without changing the fundamental laser system. By varying these parameters, the system can control output pulse energy and adapt to different measurement requirements while keeping the manufacturing complexity low
4Adaptability or versatility
If the system is used in fluctuating environments such as downhole applications, then remote monitoring is achieved, but dimensional changes caused by temperature and pressure swings reduce measurement reliability
Solution Approach 1:
The patent incorporates dynamic compensation mechanisms that actively adjust optical parameters in response to environmental changes. By making the optical system adaptable to temperature and pressure variations, the system maintains measurement reliability in remote downhole applications despite the fluctuating conditions
Solution Approach 2:
The patent uses parameter change strategies where key optical parameters (focus distance, beam expansion ratio, alignment) are adjusted to compensate for environmental effects. This allows the system to maintain optimal performance across varying temperature and pressure conditions in remote monitoring applications
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 allows for controlled laser output, reduces system sensitivity to environmental fluctuations, and increases the amount of light collected for analysis, improving the effectiveness of remote sensing in extreme conditions.
Implementation Method 1
an optical pumping source delivering pump light to a passively Q-switched laser through an optical fiber
Implementation Method 2
an adjustable focus lens arrangement expanding each of the produced pumping pulses to the laser media
Implementation Method 3
a passively Q-switched laser producing a lasing pulse after absorbing one or more of the produced pumping pulses
Implementation Method 4
a beam expander reducing the divergence and thus the lost light of collected spectral emission
Implementation Method 5
a third mirror positioned whereby at least some optical response from a sample area is reflected to the third mirror, and where the third mirror is optically connected to both the second mirror and through a spectral emission control to a fourth mirror
Implementation Method 6
laser induced breakdown spectroscopy applications
Data Source
AI summary
One or more embodiments relates to a method of growing ultrasmooth and high quantum efficiency CsTe photocathodes. The method includes exposing a substrate of Cs using an alkali source such as an effusion cell; and controlling co-evaporating growth and co-deposition forming a CsTe growth. The method further includes monitoring a stoichiometry of the CsTe growth.