The IRsweep IRis-F1 spectrometer uses a dual frequency comb laser source to provide high signal-to-noise measurements with microsecond time resolution.

This spectrometer is an excellent complement to broadband FT-IR measurements where information about the dynamics of the system of interest is limited by the useful time resolution of rapid-scan measurements or by the reproducibility requirements of step-scan measurements.

Time-Resolved Measurement Modes

There are a number of different measurement modes with implications for time resolution.

Static Measurement

Closest to a traditional FT-IR rapid-scan measurement, but with faster measurement rates and times.

• Traditional background measurement
• Sample measurements can be repeated as needed
• Rapid multiple static acquisition limited by repetition rate / signal-to-noise requirements
  • Example: 1 ms acquisition has minimum 7 ms duty cycle for up to 3.4 s with good noise floor
  • Duty cycle can be specified
  • Measurement can continue indefinitely at reduced duty cycle (256 ms for above 1 ms example)
• Start of measurement can be triggered

Triggered Static

Same as Static Measurement, except each measurement is controlled externally.

• Single trigger to collect single measurement
• Duty cycle and repetition rate are determined by external trigger

Triggered Time-Resolved

Best time resolution, similar to FT-IR step-scan measurement.

• Background is collected as pre-trigger samples for each repetition
• Requires a sample system with a reproducible trigger (like step-scan)
• Finite time window
• Sample measurement repeated to build S/N (co-addition)
• Default time resolution is 4 µs, minimum is 1 µs

More Information

The IRsweep website has an introduction to the dual-comb laser technique and advantages:

• https://irsweep.com/technology/