Amplitude-Modulated Laser Pulses for Higher Fluorescence Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing ultrashort optical pulses fail to optimize fluorescence in applications like protein or gene sequencing, as they either cause dye decay or do not increase fluorescence when using small dye quantities, leading to reduced detection efficiency.
Innovation Solution
A compact mode-locked laser module produces an amplitude-modulated pulse train with ultrashort laser pulses of varying amplitude, which increases fluorescence while minimizing dye decay by allowing the dye to recover in a non-radiative state, and automatically adjusts parameters for optimal performance with small dye quantities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the dye is excited for longer periods to increase total fluorescence, then fluorescence yield increases, but dye decay (bleaching) increases
Solution Approach 1:
The patent applies periodic pulsed excitation instead of continuous excitation. The mode-locked laser generates ultrashort pulses (≤100 ps) at controlled repetition rates, allowing the dye to fluoresce during pulse intervals and recover during off periods. This periodic action enables multiple excitation cycles before bleaching occurs, increasing total fluorescence yield while preserving dye stability.
Solution Approach 2:
The patent uses amplitude modulation to pre-shape the excitation pulse train according to the dye's fluorescence lifetime characteristics. By adjusting pulse amplitudes and intervals beforehand to match the dye's recovery time constants, the system optimizes fluorescence extraction while preventing excessive excitation that would cause bleaching.
2Reliability
If the time between excitations is increased to allow dye recovery, then dye decay is reduced, but detection rate decreases
Solution Approach 1:
The mode-locked laser provides periodic ultrashort pulses at optimized repetition rates that match the dye's fluorescence lifetime. This regular pulsing allows the dye to recover during intervals while enabling high-speed detection through the repetitive nature of the excitation, simultaneously improving dye stability and detection throughput.
Solution Approach 2:
The system dynamically adjusts the pulse repetition rate and amplitude based on the specific dye's fluorescence lifetime characteristics. This dynamic optimization allows faster detection rates for dyes with shorter lifetimes while providing adequate recovery time for dyes with longer lifetimes, maximizing both productivity and reliability across different applications.
3Quantity of substance
If conventional laser pulse trains are used to excite small dye quantities, then fluorescence is produced, but fluorescence yield is not optimized
Solution Approach 1:
The patent changes key laser parameters including pulse width (≤100 ps), repetition rate, and amplitude modulation depth to match the fluorescence lifetime of the dye. These parameter optimizations enable efficient excitation of trace dye quantities, maximizing photons emitted per dye molecule and significantly improving fluorescence efficiency for applications like single-molecule detection.
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 amplitude-modulated pulse train enhances fluorescence yield and extends the dye's non-radiative recovery time, maintaining or increasing overall fluorescence while allowing for more frequent detections without dye degradation.
Implementation Method 1
In certain embodiments, the laser is a mode-locked laser. The laser produces an amplitude-modulated pulse train.
Implementation Method 2
Ultrashort optical pulses may be useful for fluorescent lifetime imaging (FLI) and lifetime-resolved fluorescent detection. Ultrashort pulses are useful in these applications because they can cause different materials to fluoresce
Implementation Method 3
This bleaching effect can be alleviated by allowing the dye to return to a non-radiative state for some time.
Data Source
AI summary
Systems and methods are described for producing an amplitude-modulated laser pulse train. The laser pulse train can be used to cause fluorescence in materials at which the pulse trains are directed. The parameters of the laser pulse train are selected to increase fluorescence relative to a constant-amplitude laser pulse train. The amplitude-modulated laser pulse trains produced using the teachings of this invention can be used to enable detection of specific molecules in applications such as gene or protein sequencing.