Single Transmission Grating Pulse Stretcher for CPA Systems
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Solution Overview
Problem
Existing solid-state CPA systems are complex and costly due to the need for precise control of group delay dispersion (GDD), third-order dispersion (TOD), and fourth-order dispersion (FOD) through adjustments of grating incidence angles, which requires extensive realignment of beam-steering optics and multiple stages for rotation and translation, making them cumbersome and expensive.
Innovation Solution
The use of a single transmission-grating with variable incidence angle in the pulse-stretcher and fixed-angle reflection-gratings in the pulse-compressor, allowing for iterative adjustments of incidence angles and path lengths to optimize pulse parameters, simplifying the system by distributing control functions and minimizing the need for realignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If grating incidence angles are varied to control GDD and TOD, then pulse parameters can be optimized, but beam-steering optics must be realigned and multiple stages are required, increasing device complexity
Solution Approach 1:
The system separates the control of GDD and TOD into independent adjustment mechanisms: GDD is controlled by grating spacing while TOD is controlled by grating incidence angle. This segmentation allows each parameter to be adjusted independently without requiring realignment of other components, reducing overall system complexity while maintaining precise pulse parameter control
Solution Approach 2:
The pulse compressor is designed to perform multiple functions: it simultaneously compresses pulses and controls both GDD and TOD parameters. By integrating these functions into a single apparatus with appropriately designed adjustment mechanisms, the system avoids requiring separate devices for each function, thereby reducing device complexity
2Measurement precision
If grating incidence angles are varied significantly, then TOD control is improved, but beam deviation becomes large requiring realignment of beam-steering optics
Solution Approach 1:
The system decouples TOD control from beam steering by using a specific optical configuration where the incidence angle adjustment on the compressor gratings changes TOD without significantly affecting the output beam direction. This segmentation of control functions allows precise TOD adjustment without requiring subsequent realignment of beam-steering optics
Solution Approach 2:
The patent introduces an intermediate optical path configuration where the effect of incidence angle changes on beam deviation is compensated or minimized. This intermediary arrangement allows the system to achieve the desired TOD control while maintaining stable beam steering, eliminating the need for realignment
3Measurement precision
If multiple adjustment stages are used for GDD and TOD control, then pulse compression is optimized, but the apparatus becomes massive and expensive
Solution Approach 1:
The patent combines the GDD control and TOD control functions into a single integrated pulse compressor apparatus. By merging these functions and using carefully designed adjustment mechanisms that provide independent control of both parameters within the same optical path, the system achieves optimized pulse compression without requiring separate massive stages for each function, thereby reducing overall apparatus size and cost
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 simplifies the CPA system by reducing the complexity and cost, allowing for effective control of GDD and TOD with minimal deviation angle changes, thus optimizing pulse compression and shape without the need for extensive optical realignment, while maintaining efficiency and flexibility.
Implementation Method 1
a pulse-stretcher having a single transmission-grating in a multi-pass configuration at a non-normal incidence angle for temporally stretching pulses in the laser-beam
Implementation Method 2
a pulse-compressor including at least one reflection-grating in a multi-pass path configuration, for compressing the amplified temporally-stretched pulses
Data Source
AI summary
Optical apparatus for amplifying pulses in a pulsed laser-beam includes a pulse-stretcher having a single transmission-grating in a multi-pass configuration at a non-normal incidence angle. A regenerative amplifier amplifies stretched pulses in the laser-beam. A pulse-compressor including two spaced-apart reflection-gratings in a multi-pass configuration compresses the amplified pulses. Pulse-parameters of the compressed amplified pulses are optimized by iteratively adjusting the incidence angle of the pulsed laser-beam on the transmission-grating of the pulse-stretcher and the spacing between the reflection-gratings of the pulse-compressor.