Short Photonic Crystal Fiber for Efficient Femtosecond Wavelength Conversion
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Solution Overview
Problem
Existing multi-wavelength laser systems face challenges in increasing output pulse energy while maintaining the desired wavelength, particularly under high-energy conditions, and are costly and complex, making them unsuitable for neuroscience microscopy and specific spectroscopy applications.
Innovation Solution
A device utilizing a short photonic crystal fiber (PCF) with a length of ≤1.25 cm to improve laser wavelength conversion efficiency, which reduces attenuation and dispersion, and a high-power multi-wavelength femtosecond laser system comprising a NIR laser, lenses, and a PCF to generate near-infrared Cherenkov radiation suitable for multiphoton microscopes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the length of photonic crystal fiber is increased to improve wavelength conversion, then the wavelength conversion capability is enhanced, but the attenuation and dispersion increase
Solution Approach 1:
The patent changes the key parameter of fiber length from conventional long lengths to a specific short range (0.65-1.25 cm). This parameter change optimizes the balance between wavelength conversion capability and attenuation/dispersion, achieving high conversion efficiency while minimizing energy loss in the 750-1000nm band.
2Power
If the input laser power is increased to increase the Cherenkov radiation energy, then the output pulse energy is increased, but the wavelength of the output laser pulse changes
Solution Approach 1:
The patent changes the fiber length parameter to compensate for the wavelength shift caused by increased input power. The optimized short fiber length (0.65-1.25 cm) ensures that even at high input powers (up to 1000mW), the Cherenkov radiation wavelength remains within the desired 750-1000nm range, simultaneously achieving high output energy and precise wavelength control.
3Use of energy by moving object
If long optical fibers are used to improve Cherenkov radiation energy conversion efficiency, then the conversion efficiency is improved, but the system complexity and cost increase
Solution Approach 1:
The patent fundamentally changes the fiber length parameter to a short scale (0.65-1.25 cm), which simplifies the overall system structure. The short fiber configuration achieves high energy conversion efficiency (over 50% in 750-1000nm band) while reducing system complexity, eliminating the need for additional wavelength control components, and lowering overall system cost.
4Loss of energy
If the fiber length is shortened to reduce attenuation and dispersion, then the energy conversion efficiency is improved, but the wavelength conversion capability may be compromised
Solution Approach 1:
The patent identifies and optimizes the critical parameter of fiber length to a specific short range (0.65-1.25 cm). This optimized parameter simultaneously achieves multiple objectives: minimizing attenuation and dispersion while maintaining excellent wavelength conversion capability in the 750-1000nm band, proving that short fibers can be highly effective when properly designed.
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
The solution increases output pulse energy with controlled wavelength range, reduces fiber consumption, and enables deep biological imaging with high energy conversion efficiency and short pulse duration, making it suitable for two-photon microscopes.
Implementation Method 1
a wavelength conversion member photonic crystal fiber (PCF), and improves wavelength conversion efficiency by shortening the length of the PCF
Implementation Method 2
the PCF is used to broaden the wavelength window of the laser pulses transmitted inside it through Soliton self-frequency shift (SSFS) and Cherenkov radiation
Data Source
AI summary
This invention provides a device for improving laser wavelength conversion efficiency and a laser system configured to provide high-power multi-wavelength femtosecond laser pulses using the device. The device for improving laser wavelength conversion efficiency comprises a wavelength conversion member photonic crystal fiber (PCF), wherein the device for improving laser wavelength conversion efficiency improves wavelength conversion efficiency by shortening the length of the PCF. The device provided in this invention not only reduces the attenuation and dispersion caused by the optical fiber, but also improves the energy conversion efficiency within a specific wavelength range. The use of the technique not only increases the energy of light pulse, but also greatly reduces the amount of fiber used, and can maximize the energy of the desired wavelength according to experimental requirements when using laser input sources of different wavelengths.