Optical Waveguide Tip Lateral Emission via Vaporized Gas Refractive Index
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Solution Overview
Problem
Existing medical laser systems for procedures like benign prostatic hyperplasia treatment face challenges in directing laser energy laterally within confined spaces, as traditional side-firing fibers are often bulky and have reduced damage thresholds when exposed to high optical energy, and their production is complex, limiting their applicability in minimally invasive procedures.
Innovation Solution
The use of specially prepared optical waveguide tips with refractive index differences between the waveguide materials and the surrounding medium allows for peripheral emission of optical radiation, redirecting it through changes in the medium's refractive index, enabling efficient tissue ablation and vaporization with reduced probe size and increased safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional side-firing fibers are used to direct laser energy laterally, then lateral treatment capability is improved, but probe size increases and damage threshold decreases
Solution Approach 1:
The patent changes the refractive index parameter of the surrounding medium by vaporizing liquid (e.g., saline or water) to create a gas-filled environment around the fiber tip. This parameter change enables total internal reflection at the fiber-gas interface, allowing lateral light redirection without requiring complex fiber structures or increased probe size.
Solution Approach 2:
The patent replaces the mechanical/structural approach of traditional side-firing fibers (which require complex internal structures, angled facets, or reflective coatings) with an optical approach using refractive index manipulation. By changing the medium from liquid to gas through vaporization, the system achieves lateral beam redirection purely through optical physics rather than mechanical fiber design.
2Ease of operation
If traditional side-firing fibers are used to direct laser energy laterally, then lateral treatment capability is improved, but reliability decreases due to reduced damage threshold
Solution Approach 1:
The patent introduces vaporized gas as an intermediary medium between the optical fiber and the target tissue. This gas layer acts as a protective interface that enables total internal reflection for lateral beam redirection while maintaining a simple, robust fiber structure without exposed lateral facets or coatings that would be susceptible to damage.
Solution Approach 2:
The patent replaces vulnerable mechanical structures (angled fiber facets, reflective coatings, or lateral openings) with an optical solution based on refractive index manipulation. The gas-filled environment created by vaporization provides the necessary optical conditions for lateral redirection without requiring any physical modifications to the fiber tip that would reduce its damage threshold.
3Ease of operation
If complex fiber structures are used to achieve lateral light redirection, then lateral emission capability is improved, but manufacturing complexity increases
Solution Approach 1:
The system uses the treatment environment itself (the liquid medium present during the procedure) to create the desired optical conditions. By vaporizing the existing liquid medium through laser heating, the system self-generates the gas-filled environment needed for total internal reflection, eliminating the need for pre-manufactured complex fiber structures or separate gas delivery systems.
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 allows for effective and efficient treatment of tissues with reduced probe size and enhanced safety, enabling precise and powerful laser ablation and vaporization in confined medical environments, such as within the body during urological treatments.
Implementation Method 1
the surrounding medium will be changed in the vicinity of at least a part of the peripheral surface area. The changes of the surrounding medium result in a change of its refractive index
Implementation Method 2
refractive index differences between the fiber core and that of the air gap formed in the cap, and with the cap in the path of radiation transmission can be fused to the clad fiber at the distal end to reduce/eliminate Fresnel loss as the side firing fiber transmits the laser energy
Data Source
AI summary
A device for improved surgical procedures to remove unwanted or hyperplasic tissue from a patient during laser ablation, urological treatments, benign prostatic hyperplasia treatments and other applications. Specially prepared optical waveguide tips allow for enhanced irradiation of desired tissues with light sources including laser diodes, bright LEDs or lamps. A significant fraction of the optical radiation, being transported in the waveguide, is coupled out of the waveguide into the surrounding medium through a peripheral surface at or near the distal end. The optical radiation is chosen to have an appropriate wavelength and sufficient power density, so that the surrounding medium will be changed in the vicinity of at least a part of the peripheral surface area. The changes of the surrounding medium result in a change of its refractive index such that the optical radiation is redirected.