Monolithic Mode-Locked Laser Diode Write Head for Two-Photon Polymerization
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Solution Overview
Problem
Existing two-photon polymerization apparatuses are large, heavy, expensive, and inefficient due to the use of Ti: sapphire lasers, making them unsuitable for portable and cost-effective production of small, complex objects.
Innovation Solution
A write head incorporating a monolithic mode-locked laser diode and microscope objective for focusing laser radiation, allowing for localized two-photon polymerization without the need for complex optics, enabling a compact and energy-efficient apparatus for producing small, complex objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Ti: sapphire lasers are used for two-photon polymerization, then high photon density and polymerization effectiveness are achieved, but the apparatus becomes large, heavy, expensive, and energy-inefficient
Solution Approach 1:
The patent changes the key parameter of pulse duration from the conventional range (typically >100 fs for Ti: sapphire lasers) to an ultrashort range (1 fs to 100 fs, preferably 10-50 fs). This parameter change enables the use of diode-pumped solid-state lasers instead of Ti: sapphire lasers, achieving high peak intensities for two-photon polymerization while reducing apparatus size, weight, and cost by eliminating the need for optical pumping systems and complex cooling requirements
Solution Approach 2:
The patent replaces expensive, complex Ti: sapphire laser systems with more affordable, compact diode-pumped solid-state lasers. The invention accepts that shorter laser lifetimes (pulse durations) are needed to achieve high peak powers, and this trade-off enables using simpler, cheaper laser sources that don't require costly maintenance and complex optical pumping infrastructure
2Reliability
If Ti: sapphire lasers with complex optical elements are used, then two-photon polymerization can be performed, but the apparatus becomes large and requires water cooling
Solution Approach 1:
The patent extracts and removes the complex optical pumping system and water cooling infrastructure from the laser system. By using diode-pumped solid-state lasers with ultrashort pulse durations, the invention eliminates the need for complex optical elements (such as frequency doublers, mode-locking cavities, and optical pumps) and extensive water cooling systems, while maintaining reliable two-photon polymerization through high peak intensities
Solution Approach 2:
The patent substitutes the mechanical and thermal management infrastructure (water cooling systems, optical pumping mechanisms) with a more compact diode-pumped laser system. The replacement uses electrical diode pumping instead of complex optical pumping, and relies on the ultrashort pulse nature to deliver sufficient energy without requiring extensive thermal management infrastructure
3Device complexity
If direct laser radiation into starting material is desired, then simplified optics are needed, but conventional lasers require complex optical elements
Solution Approach 1:
By changing the pulse duration parameter to ultrashort ranges (1-100 fs), the patent enables direct laser radiation into the starting material without complex optical elements. The ultrashort pulses provide sufficiently high peak intensities for two-photon polymerization, allowing the laser beam to be directly focused onto the resin with minimal optical intermediaries, thereby simplifying the optical path while maintaining manufacturing precision
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 results in a significantly smaller, lighter, and more cost-effective apparatus capable of producing objects with precise control over structural properties, suitable for various applications, including microelectromechanical systems and microoptics, while maintaining acceptable process duration and efficiency.
Implementation Method 1
a monolithic mode-locked laser diode
Implementation Method 2
a microscope objective that is configured and arranged to focus laser radiation generated by the monolithic mode-locked laser diode
Implementation Method 3
In two-photon polymerization, almost simultaneous (quasi-simultaneous) absorption of two photons results in polymerization
Implementation Method 4
The starting material is cured by two-photon polymerization locally where the intensity of the laser radiation is sufficiently high
Data Source
AI summary
A write head for producing an object by way of two-photon polymerization, comprising:a monolithic mode-locked laser diode,a microscope objective that is configured and arranged to focus laser radiation generated by the monolithic mode-locked laser diode.