Variable Delay Optical Assembly with Temperature Compensation
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Solution Overview
Problem
Conventional optics arrangements for generating a variable delay between light pulses are either mechanically complex, costly, or require high adjustment efforts, limiting their precision and practicality for applications like spectroscopic investigations and THz time-domain spectroscopy.
Innovation Solution
An optics arrangement featuring a pulsed light source with a variable pulse repetition rate, a pulse splitter, a temperature stabilizer, and a temperature compensator, along with a control circuit to maintain precise time delay, reduces the need for mechanical adjustments and electronic synchronization, enhancing precision and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical optical delay line is used to change the delay between light pulses, then the delay can be adjusted, but the system requires high mechanical precision and significant adjustment effort
Solution Approach 1:
The patent replaces the mechanical optical delay line with an electronic control system that adjusts the pulse repetition rate of the laser source. Instead of physically moving mirrors or delay elements mechanically, the system uses electronic modulation of the laser's pulse generation rate to achieve variable delay between pulse pairs, eliminating mechanical adjustment requirements while maintaining precision.
Solution Approach 2:
The patent changes the pulse repetition rate parameter of the laser source to control the delay between pulse pairs. By electronically adjusting the repetition rate around a central value, the system varies the time delay between consecutive pulses without any mechanical movement, thus achieving precise delay control with minimal adjustment effort.
2Measurement precision
If two synchronous lasers are used for asynchronous optical sampling, then variable delay can be achieved, but the system becomes costly and complex due to electronic synchronization requirements
Solution Approach 1:
The patent merges the functions of two separate laser sources into a single laser source that generates pulse pairs. Instead of using two independent lasers that require electronic synchronization, one laser generates both pulses in each pair with a fixed internal delay, eliminating the need for complex electronic synchronization circuits while maintaining precise delay control through repetition rate modulation.
Solution Approach 2:
The single laser source performs multiple functions: it generates both pulses in the pair, provides the delay mechanism through its pulse train structure, and enables delay variation through repetition rate modulation. This multi-functional approach replaces the need for two specialized laser sources and their synchronization infrastructure.
3Ease of operation
If the pulse repetition rate is varied to achieve variable delay, then adjustment effort is reduced, but temperature changes affect the delay precision
Solution Approach 1:
The patent implements a feedback control system that monitors the actual pulse delay (derived from the pulse pair timing) and adjusts the pulse repetition rate to compensate for temperature-induced drifts. The control circuit continuously corrects the repetition rate to maintain the desired delay precision despite environmental temperature variations, ensuring stable operation without manual recalibration.
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 provides a robust and precise method for generating variable time delays between light pulses, improving the accuracy and reliability of applications such as spectroscopic investigations and THz time-domain spectroscopy by stabilizing the delay element and compensating for temperature-induced changes.
Implementation Method 1
The optical arrangement has a temperature stabilizer for thermally stabilizing the delay element
Implementation Method 2
a temperature compensator for compensating for temperature-dependent changes in the optical path length of the delay element
Implementation Method 3
For this purpose, for example, the resonator length of the pulsed light source can be varied
Data Source
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AI summary
The assembly (1) has a pulsed light source (2) generating primary light pulses (4), and a pulse splitter (5) splitting the primary light pulses into first and second secondary light pulses (7). A temperature stabilizer (16) stabilizes a delay element (8), which delays the second pulse relative to the first pulse. A temperature compensator (13) compensates a temperature-dependent change of an optical path length of the delay element. A control circuit controls a pulse repetition rate of the light source to detect and control a drift of a mean pulse repetition rate of the light source. The delay element is designed as a glass fiber. The pulsed light source is designed as a short-pulse laser or an ultra short-pulse laser. The temperature compensator is designed as a controllable fiber stretcher. An independent claim is also included for a method for generating light pulses.