Linear Motor Tuning Laser Cavity Wavelength

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Solution Overview

Problem

Existing tunable lasers suffer from slow wavelength tuning speeds and mechanical wear, making them unsuitable for rapid and precise wavelength changes required in many life science applications.

Innovation Solution

The use of a linear motor to move a wavelength selective element within the laser cavity, enabling fast and backlash-free tuning of the center wavelength, combined with a prism pair for dispersion compensation and an aperture for filtering, allowing for rapid wavelength changes without sacrificing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a lead screw driven translation stage with encoded servo or stepper motor is used to move the prism, then the setup is mechanically simple and easy to control, but the tuning speed is slow and mechanical wear occurs over time

Engineering Contradiction:
Improvewavelength tuning speedVSAvoidmechanical wear
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent replaces the lead screw driven mechanical transmission system with a linear motor that directly drives the translation stage. This substitution eliminates the lead screw mechanism entirely, removing the source of mechanical wear while enabling faster acceleration and tuning speeds. The linear motor provides direct electromagnetic force conversion to linear motion, achieving both speed improvement and reliability enhancement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If a linear motor is used to move the translation stage, then the tuning speed increases significantly and mechanical wear is eliminated, but the device complexity increases

Engineering Contradiction:
Improvewavelength tuning speedVSAvoidmotor system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the lead screw mechanism from the system, eliminating the complex mechanical transmission components. By taking out the lead screw, the system reduces mechanical complexity while simultaneously improving reliability and speed. The linear motor directly converts electrical energy to linear motion without intermediate mechanical transmission elements.

Inventive Principle:
Principle #2Taking out (Extraction)

3Speed

If the prism is moved rapidly to achieve fast wavelength changes, then the tuning speed improves, but the motion may become less smooth and affect active lasing

Engineering Contradiction:
Improvewavelength tuning speedVSAvoidmotion smoothness
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent utilizes the dynamic capabilities of linear motors to achieve high acceleration and speed while maintaining smooth motion. The linear motor's ability to provide precise control over force and position allows for optimized motion profiles that balance speed and smoothness. The contactless operation inherent in linear motors eliminates mechanical friction and backlash, ensuring smooth motion even at high speeds during active lasing.

Inventive Principle:
Principle #15Dynamics

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 wavelength changes of several hundred nanometers in less than 100 ms with high accuracy and smooth motion, reducing the need for multiple lasers in experiments.

Implementation Method 1

A linear motor is configured to move a translation stage

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Implementation Method 2

the light inside the laser cavity is separated by wavelength through the prisms

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

A first prism and a second prism are located between the gain medium and the reflecting mirror

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 4

the aperture filters out the desired wavelength

Methodology Applied
Scientific EffectGeometric filtering: Filter (optical)

Implementation Method 5

A pump source is configured to energize the gain medium

Methodology Applied
Scientific EffectStimulated emission: Laser

Data Source

PatentEP3363085B1Linear motor for fast tuning of a laser cavity
Publication Date: 2023.05.10 THORLABS INC
  • EP3363085B1 patent drawingFigure 1
  • EP3363085B1 patent drawingFigure 2
  • EP3363085B1 patent drawingFigure 3

AI summary

A tunable laser including: a reflecting mirror; a partially transmitting mirror; a gain medium energized by a pump source; a pair of mirrors surrounding the gain medium, a first prism and a second prism located between the gain medium and the reflecting mirror; the first prism receives radiation from the gain medium and disperses the radiation to the second prism; the second prism receives and directs the radiation towards an optical element which filters the spatially dispersed radiation based on the position to the second prism, the radiation resonates between the reflecting mirror and the partially transmitting mirror; the second prism is placed on a stage moved by a linear motor such that a desired center wavelength is obtained by moving the second prism to a position so as to allow radiation having the desired center wavelength to resonate between the reflecting mirror and the partially transmitting mirror.