Terahertz Waveform Acquisition via Temperature-Dependent Delay Medium
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Solution Overview
Problem
Existing terahertz wave temporal waveform acquisition apparatuses face challenges in miniaturization due to the use of mechanical delay mechanisms, which are difficult to shrink in size.
Innovation Solution
A terahertz wave temporal waveform acquisition apparatus utilizing a delay providing medium with a temperature-dependent refractive index, allowing for optical path length adjustments via temperature changes, instead of mechanical means, to synchronize the terahertz wave and probe light inputs to the detection element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a mechanical delay providing mechanism is used to sweep the input timing of the terahertz wave or probe light, then the temporal waveform of the electric field amplitude can be obtained, but the apparatus cannot be miniaturized due to the difficulty of shrinking the mechanical stage
Solution Approach 1:
The patent replaces the mechanical delay providing mechanism with a temperature control mechanism. Instead of mechanically moving mirrors or stages to adjust optical path length, the invention uses temperature-dependent refractive index changes in a delay providing medium to achieve the same timing delay effect, thereby enabling miniaturization while maintaining delay adjustment capability
Solution Approach 2:
The patent changes the physical parameter (temperature) of the delay providing medium to achieve delay adjustment. By controlling the temperature of the medium with temperature-dependent refractive index, the optical path length is dynamically adjusted without mechanical movement, solving the contradiction between miniaturization and operational capability
2Measurement precision
If the pulse width of the probe light is made narrower than that of the terahertz wave by several digits, then higher time resolution is achieved, but the synchronization and timing control becomes more difficult
Solution Approach 1:
The patent employs feedback mechanisms through correlation detection between the terahertz wave and probe light. The detection element measures the correlation value, and this information is used to optimize the timing synchronization, thereby managing the complexity of controlling ultrashort pulse synchronization effectively
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 miniaturization of the apparatus while maintaining the ability to accurately measure terahertz wave temporal waveforms, improving signal-to-noise ratio and reducing the complexity of the optical system.
Implementation Method 1
a delay providing medium disposed on an optical path of the terahertz wave from the terahertz wave generation element to the terahertz wave detection element, formed of a material of which a refractive index for the terahertz wave depends on the temperature, and configured to provide a delay according to the temperature to the terahertz wave
Implementation Method 2
the terahertz wave and the probe light are coupled by a coupling part and input to the electrooptical crystal, a birefringence is induced in the electrooptical crystal along with propagation of the terahertz wave, and the birefringence changes a polarization state of the probe light
Implementation Method 3
a current expressing the correlation value between the terahertz wave and the probe light is generated between two electrodes of the photoconductive antenna element according to the inputs of the terahertz wave and the probe light
Data Source
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AI summary
A terahertz wave temporal waveform acquisition apparatus (1) includes a light source (10), a branch pant (20), a terahertz wave generation element (31), a terahertz wave detection element (32), a delay providing medium (40), a temperature adjustment unit (50), and an analysis unit (60). The delay providing medium is disposed on an optical path of a terahertz wave (LT) from the terahertz wave generation element to the terahertz wave detection element, is formed of a material of which a refractive index for the terahertz wave depends on the temperature, and provides a delay according to the temperature to the terahertz wave. Accordingly, the terahertz wave temporal waveform acquisition apparatus which is capable of easily being miniaturized is realized.