Raman Tools
Acquisition time and signal-to-noise ratio (SNR)
You improve a weak Raman signal over time: in a shot-noise-limited measurement, SNR increases with the square root of time. Check how much integration time (or how many accumulations) is needed to go from the current SNR to the target SNR — and why a twofold better signal costs four times longer.
Starting point and target
Model and assumptions
SNR ∝ √(time) (shot-noise-limited measurement)
t₂ = t₁ · ( SNR₂ / SNR₁ )²
N accumulations = t₂ / single accumulation time
The square-root relationship holds when signal/background shot noise dominates (typical for longer integrations). When detector readout noise dominates, accumulating many short frames may be worse than a single long exposure. Fluorescence background also scales with time — if it is the limiting factor, simply extending acquisition time will not help (consider a different laser).
Approximate result — actual time depends on laser power, optics, detector, and the sample itself.
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