Pump Probe Device Optical Delay Modulation
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Solution Overview
Problem
Conventional pump probe measuring devices struggle to perform high-sensitivity measurements for fast phenomena occurring at 1 ns or faster due to limitations in modulation amplitude and frequency, leading to inaccurate results and mechanical vibrations.
Innovation Solution
A pump probe measuring device that uses an ultrashort optical pulse laser generator with multiple optical delay units and optical shutters, allowing for high-speed and large-amplitude delay time modulation without mechanical vibrations, enabling precise measurement of ultrafast phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mirror position is varied periodically to perform delay time modulation, then the delay time can be controlled precisely, but the modulation amplitude is limited and mechanical vibrations are generated
Solution Approach 1:
The patent replaces the mechanical mirror vibration system with an optical path length adjustment system using a retroreflector and lens. Instead of mechanically vibrating a mirror to modulate delay time, the system uses optical elements to achieve delay time modulation without mechanical vibrations, thereby eliminating the harmful vibrations while maintaining precise control.
2Measurement precision
If the mirror position is varied with large amplitude to achieve high modulation depth, then the measurement sensitivity is improved, but the modulation frequency must be extremely low
Solution Approach 1:
The patent eliminates the mechanical constraint by replacing the mirror vibration system with an optical path length adjustment system. This allows large amplitude delay time modulation to be achieved without the mechanical limitations that forced the modulation frequency to be extremely low, thereby improving both measurement sensitivity and modulation frequency.
3Duration of action of moving object
If mechanical vibration is used to modulate delay time, then the delay time can be modulated periodically, but the mechanical deformation of the driving mechanism prevents accurate modulation
Solution Approach 1:
The patent substitutes the mechanical vibration-based delay time modulation with an optical path length adjustment system. This replacement eliminates the mechanical deformation issues that degraded modulation accuracy, while still achieving periodic modulation capability through the optical system.
4Device complexity
If conventional delay time modulation is used, then the setup is simple, but it cannot perform high-sensitivity measurements for fast phenomena at 1 ns or faster
Solution Approach 1:
The patent replaces the conventional mechanical delay time modulation system with an optical path length adjustment system using retroreflector and lens. This substitution enables high-sensitivity measurements for fast phenomena at 1 ns or faster by eliminating mechanical vibrations and improving modulation performance, while maintaining relative simplicity of the setup.
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 highly sensitive and stable measurement of faint signals across a wide range of relaxation times, including phenomena as short as picoseconds, with improved time-resolved scanning capabilities.
Implementation Method 1
an optical parametric amplifier 54 for amplifying the optical pulses
Implementation Method 2
a piezoelectric element 52 for changing the optical path length of the probe light
Implementation Method 3
the laser pulse from the light source is divided by a half mirror 1 (HM1) into two optical paths
Data Source
Figure 1
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Figure 3
AI summary
A pump probe measuring device (1) comprises: an ultrashort optical pulse laser generator (2) for generating a first ultrashort optical pulse train which is a pump light (3a), second and third ultrashort optical pulse trains (3b), (3c) which are probe lights; an optical shutter unit (6) to which the second and the third ultrashort pulse trains (3b), (3c) are introduced; and a detecting unit (20) including an irradiation optical system (8) for directing the pump light (3a), the first probe light (3b) and the second probe light (3c) to a sample (7), a sensor (11) for detecting a probe signal from the sample (7), and a phase-sensitive detecting means (12) connected to the sensor (11). An optical shutter control unit (10) periodically modulates the delay time of the first probe light (3b) and that of the second probe light (3c) with respect to the pump light (3a), and the modulated first and second probe lights (3a), (3b) illuminate the sample (7) alternately to detect the probe signals from the sample (7) by the phase-sensitive detecting means (12) in synchronization with the periodic modulation signal of the delay time.