Please follow these steps in order:

1. Prepare a spectral data file (CSV): two columns are required. Column 1 is wavelength in meters (m). For example, 700 nm should be written as 700e-9 (not 700). Column 2 is the corresponding spectral intensity.
2. Note: the file should contain data only; do not include any header row or comment lines.
3. Note: the wavelength range should strictly match the full spectral base width. For example, if the center wavelength is 800 nm and the base spans 750–850 nm, then the left boundary should be 750 nm and the right boundary should be 850 nm. Remove any extra data outside this range.
4. Open the tool: start the Fourier-Limited Pulse Width Calculator and click “Choose File”, then select your prepared spectral data file.
5. Process data: the tool will automatically read and preprocess the file, compute the spectral center wavelength, and generate plots to visualize the spectrum. It will also calculate the pulse duration and display it in the output area.
6. Analyze results: the computed pulse width will be shown. Use the generated plots to better interpret and analyze your data.
7. When importing a new dataset, please refresh the page first.
8. Authors: Pengfei Wang, Cheng Liu, ChatGPT-4.0, Shanghai YLaser Femtosecond Laser Technology Co., Ltd.
9. You may contact us for guidance.