Q-Switched Thulium Fiber Laser Deterrence Within MPE Limits
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Solution Overview
Problem
Existing deterrent systems using photonic energy, such as lasers, often cause permanent thermal tissue damage due to prolonged exposure, and there is a need for a non-contact method to induce temporary pain without exceeding Maximum Permissible Exposure (MPE) limits.
Innovation Solution
Utilizing a Thulium Fiber Laser (TFL) with nano-pulsing and quality switching to deliver ultra-fast pulses that trigger nociceptors, ensuring photodisruption without photoablation, and an AI system for real-time control and targeting to manage laser characteristics within MPE limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photonic deterrent such as lasers is applied to induce pain response, then the deterrent effect is improved, but permanent tissue damage may occur due to prolonged exposure
Solution Approach 1:
The patent applies periodic pulsed laser action instead of continuous exposure. The laser delivers high-energy pulses at specific intervals (e.g., 10-1000 Hz repetition rates), allowing tissue to cool between pulses. This periodic delivery maintains deterrent effectiveness while preventing cumulative thermal damage that would occur with continuous exposure.
Solution Approach 2:
The patent uses preliminary cooling measures before laser application and between pulses. The system incorporates cooling intervals and may apply topical cooling agents to the treatment area beforehand, preparing the tissue to withstand the laser energy without exceeding thermal damage thresholds.
2Reliability
If laser energy is increased to enhance photodisruption effect, then nociceptor activation is improved, but photoablation and thermal damage risk increases
Solution Approach 1:
The patent precisely controls multiple laser parameters including pulse duration (nanosecond to microsecond range), repetition rate (10-1000 Hz), and energy per pulse. By optimizing these parameters, the system achieves sufficient nociceptor activation for effective deterrence while maintaining energy levels below the threshold for photoablation and thermal damage.
Solution Approach 2:
The patent employs continuous pulsed delivery rather than intermittent high-energy bursts. The laser operates continuously at a controlled pulse repetition rate, delivering lower energy pulses in succession. This maintains cumulative thermal effect for nociceptor activation without reaching the intensity required for photoablation.
3Reliability
If pulse duration is extended to increase energy delivery, then deterrent effectiveness is improved, but tissue temperature increases leading to permanent damage
Solution Approach 1:
The patent uses periodic pulsing with sufficient intervals between pulses to allow thermal dissipation. The pulse duration is optimized (nanosecond to microsecond) to deliver necessary energy while the repetition rate is controlled to ensure tissue temperature returns toward baseline between pulses, preventing cumulative heating and permanent damage.
Solution Approach 2:
The patent dynamically adjusts pulse duration and repetition rate based on treatment requirements and tissue response. The system can vary pulse width from nanoseconds to microseconds and modulate repetition frequency, allowing optimization of energy delivery while maintaining tissue temperature within safe limits through real-time parameter adjustment.
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
Induces temporary pain reactions effectively while avoiding permanent tissue damage, allowing for safe and controlled deterrence of unauthorized access to secured areas.
Implementation Method 1
A 2 μm Thulium Fiber Laser (TFL), which may be nano-pulsed, may be capable of inducing a photodisruptive effect by triggering the nociceptors. When the TFL is configured to ultra-fast pulses (e.g., 10 ps to 100 ns) with the adequate amount of energy density, it will induce photodisruption rather than photoablation
Implementation Method 2
This higher absorption rate than other lasers wavelengths such as Holmium: YAG laser around 2120 nm wavelength. This higher water absorption coefficient means that the photodisruption action causes a 'shock wave' which will have significant deterrent effect
Implementation Method 3
the water absorption coefficient, which determines the absorption by water of radiation emitted by a laser, is near peak levels. For a TFL at around a 1940 nm wavelength, the water absorption coefficient is μa=129.2 cm−1 which is near the absolute peak water absorption coefficient of around 140 cm−1
Data Source
AI summary
A deterrent apparatus, method and system including a laser configured to operate between 1000 nm and 2100 nm, a controller, and a detector. The controller is configured to instruct the laser to apply Q-switch pulses of laser to act as a deterrent to a subject. The laser may be a Thulium Fiber Laser, configured to operate between 1800 nm and 2100 nm. The laser may be a YAG Laser, configured to operate between 1000 nm and 2000 nm.