FLIM approach using modulated excitation and phase/modulation analysis to determine lifetime.
Imagine shining a flickering light on fluorophores. The fluorescence also flickers, but with a delay (phase shift) and reduced contrast (demodulation).
Both effects arise because the excited state has a finite lifetime:
For single-exponential decay, τφ = τm. Disagreement indicates multi-exponential decay—multiple lifetime components.
The Idea: Instead of pulsed excitation, use light that smoothly oscillates in brightness. The fluorescence follows but is delayed and damped. These effects reveal the lifetime.
Both approaches measure the same physical property (lifetime) using different methods:
QF-ProLoading... systems can use either approach; the choice depends on specific application requirements.
Two ways to measure lifetime:
Same physics, different measurement strategy.
