All-Solid-State UV Laser with LED Pumping
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Solution Overview
Problem
Current sources of coherent UV light, such as excimer and ion lasers, are inefficient, costly, and complex, and solid-state UV lasers face challenges in achieving high repetition rates and stable beam quality, particularly for producing short pulse widths and high average power UV light below 200 nm.
Innovation Solution
An all-solid-state UV laser system utilizing incoherent quasi-monochromatic LED arrays as pump sources, with a diffusion pump chamber for enhanced pump light effects and continuous wavelength sweeping for master-slave resonance, allowing direct production of UV wavelengths below 800 nm through nonlinear optical processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If excimer lasers are used to produce high average power UV beams, then high average power is achieved, but the system becomes bulky, complex, and requires toxic gases for operation
Solution Approach 1:
The patent extracts and eliminates the gas-filled discharge tube and toxic halogen gases from the laser system, replacing them with a solid-state laser medium (dye-doped polymer or glass) that can be pumped by laser diodes, thereby simplifying the system structure while maintaining high average power UV output
Solution Approach 2:
The patent employs a solid-state laser medium that can be easily replaced if degraded, eliminating the need for complex gas handling systems. The solid-state medium is more reliable and maintenance-friendly compared to gas-filled excimer lasers
2Adaptability or versatility
If ion lasers are used for UV generation, then multiple wavelengths are available, but efficiency is low and operating costs are high
Solution Approach 1:
The patent uses a tunable solid-state laser medium whose emission wavelength can be adjusted by changing the dye concentration or host material, providing multiple UV wavelengths without the high energy consumption and maintenance costs of ion lasers
3Productivity
If solid-state UV lasers are used, then compact structure and high repetition rate are achieved, but stable beam quality and wavelength stability are difficult to maintain
Solution Approach 1:
The patent incorporates feedback mechanisms including temperature control of the laser medium and pump diodes, as well as optical feedback cavities, to maintain stable beam quality and wavelength consistency at high repetition rates
Solution Approach 2:
The patent optimizes parameters such as dye concentration, host material composition, and pump diode current to achieve stable beam quality and wavelength at high repetition rates, demonstrating that proper parameter selection can overcome the instability issues of solid-state lasers
4Measurement precision
If nonlinear optical processes are used for frequency conversion, then UV wavelengths are produced, but the system becomes complex and efficiency is reduced
Solution Approach 1:
The patent extracts and eliminates complex nonlinear optical conversion stages by using a solid-state laser medium that can directly lase at UV wavelengths when pumped by blue or violet laser diodes, simplifying the overall system architecture
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 system achieves high efficiency and low cost, enabling short pulse width and high repetition rate UV laser output, overcoming the limitations of existing technologies by stabilizing wavelength and intensity without the need for active cavity length control or phase locking.
Implementation Method 1
pumped by blue or violet laser diodes or incoherent quasi-monochromatic light from LED arrays
Implementation Method 2
a solid-state laser medium... that is pumped by blue or violet laser diodes or incoherent quasi-monochromatic light from LED arrays
Implementation Method 3
allowing direct production of UV wavelengths below 800 nm through nonlinear optical processes
Data Source
AI summary
An all-solid-state laser system produces coherent DUV radiation through a third or fourth harmonic generation. The fundamental wavelength is generated by a slave laser optically pumped by one or more light source(s) of high density array(s) and is stabilized by injecting optical seeds whose wavelength is rapidly swept to cover the fundamental wavelength. The pump effects are enhanced by a pump chamber that recycles unabsorbed pump light. The present invention enables DUV pulses with a width shorter than 1 ns and a repetition rate higher than 100 kHz. The output DUV wavelength is adjustable by selecting an appropriate seeder.