Laser Energy Meter Circuit for High-Pulse Measurement

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Solution Overview

Problem

Existing laser energy meters are inadequate for measuring excitation and ionization laser energy above 100 joules, as they often become damaged or provide false readings when exceeding this threshold, and are expensive for a wide range of wavelengths.

Innovation Solution

A laser energy meter circuit comprising a pyroelectric detector head, amplifier, sample-and-hold circuit, trigger circuit, switched capacitor bank, and peak detector circuit, which converts pulsed output voltage into a continuous signal to measure the maximum voltage of laser pulses, allowing for accurate measurement of excitation and ionization energy in high-resolution spectroscopy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing laser energy meters are used to measure high-energy laser pulses, then measurement capability is provided, but the meters become damaged or provide false readings when energy exceeds 100 joules

Engineering Contradiction:

Improvelaser energy measurement accuracyVSAvoidmeter reliability at high energy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The measurement system is segmented into multiple stages: pyroelectric detector for initial signal capture, amplifier for signal enhancement, sample-and-hold circuit for peak voltage capture, and peak detector for final measurement. This segmentation allows each component to operate within its optimal range, preventing damage while maintaining measurement accuracy for high-energy pulses above 100 joules

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sample-and-hold circuit acts as an intermediary between the amplifier and peak detector, capturing and holding the maximum pulse voltage. This intermediary component protects the measurement system by isolating the peak detector from direct exposure to high-energy pulse signals, enabling reliable measurement without damage or false readings

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional energy meters are used for wide range of wavelengths, then versatility is improved, but cost increases significantly

Engineering Contradiction:

Improvewavelength range coverageVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The pyroelectric detector head is inherently a broadband detector that can detect laser pulses across a wide range of wavelengths without requiring wavelength-specific components. This universal detection capability, combined with the wavelength-independent sample-and-hold and peak detection circuits, provides versatile wavelength coverage at lower cost compared to conventional specialized meters

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If laser energy measurement capability is extended beyond 100 joules, then measurement range is improved, but risk of damage and false readings increases

Engineering Contradiction:

Improveenergy measurement rangeVSAvoidmeasurement reliability at high energy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The sample-and-hold circuit performs preliminary action by capturing and holding the maximum pulse voltage before it reaches the peak detector. This preliminary capture ensures that the full dynamic range of high-energy pulses (beyond 100 joules) is recorded accurately, while the held voltage protects subsequent components from damage and prevents false readings

Inventive Principle:

Principle #10Preliminary action

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 precise measurement of short and low-intensity laser pulses, maintaining voltage constant until the next trigger pulse, and interfaces with digital oscilloscopes to accurately measure laser energy beyond the previous limitations, ensuring reliable data acquisition.

Implementation Method 1

a pyroelectric detector head configured to receive laser pulses and output current signals proportional to the laser pulses

Methodology Applied

Scientific EffectPyroelectric effect: Pyroelectric Effect

Data Source

PatentUS11435232B1Energy meter circuit for short and low-intensity laser pulses

Publication Date: 2022.09.06 KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS

AI summary

A laser energy meter circuit, method, and system for measuring excitation and ionization of a reactant. The laser energy meter circuit includes a pyroelectric detector head configured to receive laser pulses and output current signals; an amplifier having a first amplifier input and an amplifier output configured to generate amplified voltage signals; a sample-and-hold circuit; a trigger circuit connected to a second sample-and-hold input, wherein the trigger circuit is configured to receive a TTL signal and generate a delayed output pulse, Q1 and a trigger signal, Q2; a sample-and-hold circuit output configured to output the maximum pulse voltage when the trigger signal is received at the second sample-and-hold input; a switched capacitor bank connected to the sample-and-hold circuit output; and a peak detector circuit configured to measure a magnitude of the maximum pulse voltage and generate an averaged DC maximum pulse voltage signal.