Rapidly Tunable Laser Source Assembly Grating Mover
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Solution Overview
Problem
Existing laser sources are not capable of quickly and accurately generating light over a broad spectral range, which limits their effectiveness in applications such as absorption spectroscopy where gases in the mid-infrared range need to be identified.
Innovation Solution
A laser assembly with a gain medium, a grating positioned in the beam path, and a mover assembly that includes both coarse and fine movers to precisely move the grating over a large range, allowing for rapid and accurate wavelength tuning without mode hops, combined with a control system and temperature controller for precise operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single mover is used to position the grating, then the device complexity is reduced, but the tuning speed and accuracy across a broad spectral range cannot be achieved
Solution Approach 1:
The mover assembly is segmented into two independent movers: a coarse mover for large-range positioning and a fine mover for precise wavelength adjustment. This segmentation allows each mover to be optimized for its specific function, achieving both fast tuning speed and high accuracy without requiring a single complex mover system
Solution Approach 2:
The system dynamically switches between coarse and fine movers based on the required adjustment range. The coarse mover handles large spectral range changes while the fine mover handles precise wavelength setting, enabling the system to adapt its movement characteristics to the operational requirements
2Measurement precision
If a single mover is used to position the grating, then the device complexity is reduced, but the accuracy of wavelength positioning cannot be achieved
Solution Approach 1:
The positioning function is segmented between coarse and fine movers, where the fine mover specifically addresses the accuracy requirement for wavelength positioning. This allows the fine mover to be designed with higher precision components without compromising the overall system simplicity
Solution Approach 2:
The fine mover acts as an intermediary between the coarse mover's large-range positioning and the grating's precise wavelength setting. It refines the position established by the coarse mover to achieve the required wavelength accuracy
3Speed
If the grating is moved over a large range quickly, then the tuning speed is improved, but the accuracy and stability of wavelength setting may be compromised
Solution Approach 1:
The grating movement is segmented into two phases: a fast coarse movement phase for rapid wavelength range switching, and a slow fine adjustment phase for stable and accurate wavelength setting. This segmentation allows the system to achieve both high speed and high reliability in different operational stages
Solution Approach 2:
The tuning process follows a periodic pattern of coarse adjustment followed by fine adjustment. This periodic action ensures that every wavelength change, regardless of magnitude, follows the same two-stage process that guarantees both speed and stability
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
Enables the generation of a continuous wave or pulsed output beam with near-diffraction limited divergence and narrow linewidth, capable of spanning a large wavelength range in the mid-infrared spectrum, facilitating fast and accurate tuning for applications like gas detection and imaging.
Implementation Method 1
the fine mover can include a piezoelectric motor
Implementation Method 2
a grating positioned in a path of the beam
Data Source
AI summary
A laser assembly (10) that generates a beam (12) includes (i) a gain medium (22) that generates the beam (12) when electrical power is directed to the gain medium (22); (ii) a grating (32) positioned in a path of the beam (12); (iii) a grating arm (34) that retains the grating (32); and (iv) a mover assembly (36) that moves the grating arm (34) about a pivot axis (38). The mover assembly (36) includes a coarse mover (344) that makes large scale movements to the grating arm (34), and a fine mover (352) that makes fine movements to the grating arm (34). With this design, the mover assembly (36) can quickly and accurately move the grating (32) over a relatively large range.