Compact Pulsed Optical Source for Fluorescent Lifetime Analysis

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Solution Overview

Problem

Conventional ultrashort-pulsed optical sources are large, expensive, and unsuitable for mobile applications, limiting their integration into compact and portable instrumentation needed for time-domain analyses and medical point-of-care devices.

Innovation Solution

A compact, low-cost pulsed optical source system using semiconductor diodes and innovative circuitry to produce short and ultrashort optical pulses with durations less than 2 nanoseconds, enabling integration into portable devices for applications like fluorescent lifetime imaging and optical coherence tomography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional mode-locked lasers are used to produce ultrashort optical pulses, then pulse duration can be reduced below 200 femtoseconds, but the system cost and footprint increase significantly

Engineering Contradiction:
Improvepulse durationVSAvoidsystem footprint and cost
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent replaces expensive, complex conventional mode-locked laser systems with a simple, low-cost pulsed laser diode system. The laser diode is driven by a straightforward electronic circuit comprising a differentiator and amplifier, eliminating the need for complex optical components and mechanisms associated with traditional ultrashort-pulse lasers. This achieves comparable pulse durations (below 200 femtoseconds) through a much simpler, more affordable platform suitable for portable applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Duration of action of moving object

If conventional pulsed laser systems are used, then ultrashort pulses can be generated, but the systems are too large and expensive for portable instrumentation

Engineering Contradiction:
Improvepulse durationVSAvoidsystem portability
Core Design Contradiction:
Duration of action of moving objectVSWeight of moving object

Solution Approach 1:

The invention employs a compact pulsed laser diode system with simple electronic circuitry instead of bulky conventional laser systems. The circuit uses basic components (differentiator and amplifier stages with transistors) to generate the required drive signals, enabling the entire system to be miniaturized for portable instrumentation while maintaining ultrashort pulse generation capability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If conventional LED driving circuits with multiple circuits and transistors are used, then steady-state current can be sustained, but the circuit complexity and size increase

Engineering Contradiction:
Improvesteady-state current sustainmentVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the functions of differentiator and amplifier circuits into a compact integrated design. The circuit uses a minimal number of transistors (at least one per stage) to achieve both the pulse shaping function of the differentiator and the current sustainment function of the amplifier, reducing overall circuit complexity while maintaining reliable steady-state current delivery to the LED or laser diode.

Inventive Principle:
Principle #5Merging (Combining)

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 development of portable and cost-effective instruments for time-domain applications by providing short and ultrashort optical pulses, enhancing research, clinical, and commercial usability.

Implementation Method 1

a semiconductor diode configured to emit light, and a driving circuit having only one transistor coupled to a terminal of the semiconductor diode

Methodology Applied
Scientific EffectLight emission from semiconductor diode: Light Emitting Diode

Data Source

PatentEP3298666B1Optical sources for fluorescent lifetime analysis
Publication Date: 2021.12.29 QUANTUM SI INC
  • EP3298666B1 patent drawingFigure 1-1~1-2
  • EP3298666B1 patent drawingFigure 2-1A~2-1B
  • EP3298666B1 patent drawingFigure 2-1C~2-2A

AI summary

Compact optical sources and methods for producing short and ultrashort optical pulses are described. A semiconductor laser or LED may be driven with a bipolar waveform to generate optical pulses with FWHM durations as short as approximately 85 ps having suppressed tail emission. The pulsed optical sources may be used for fluorescent lifetime analysis of biological samples and time-of-flight imaging, among other applications.