• Ultrashort pulse characterization
  • MHz and kHz characterization
  • Power monitoring
  • Evaluation of pulse duration

Femtometer™ is a Michelson interferometer-based autocorrelator, combined with high quality computerized data acquisition, processing and evaluation software, developed for ultrashort pulse characterization. It consists of a compact interferometer head, a spectrometer and a controller interface. Femtometer is the only computerized pulse characterization tool that provides access to the time scale of the light oscillation period allowing the measurements of few-cycle pulses.


Combining data in the time and frequency domain allows efficient characterization, evaluation and documentation of the laser pulses. With the new compact design, Femtometer requires minimal space since it can be positioned either horizontally or vertically.

Ultrafast and Versatile

The Femtometer dispersion compensated design offers high fidelity pulse measurement down to 5 fs. It offers unique flexibility due to the removable detection modules, allowing the characterization of ultrafast oscillators using the MHz detector and of amplified pulses using the kHz detector. Operation as a plain Michelson interferometer is also possible. A special MHz detector is available for measurements in the focus of microscopes. Combined with a laptop computer (not included) for data acquisition, Femtometer yields a portable characterization tool offering several data export options.

Digital Storing Oscilloscope

The oscilloscope software module, designed to display the autocorrelation trace, offers a large display and all necessary settings for efficient, easy handling.

Spectrometer Module

The spectrometer software module shows the laser spectrum, including center wavelength and FWHM bandwidth.

Online Evaluation

Standard features are calculations of center wavelength, spectral width and pulse duration. The system is self-calibrating, based on the speed of light.


Interferometric autocorrelation
Background free autocorrelation
Coherence function measurement
Spectral characterization


Interferometer HeadkHz DetectorMHz DetectorMHz Detector / Microscopy3  
Delay Range 70 µm (150 µm optional)  
Spectral Range2 650–950 nm  
Accepted Repetition Rate ≥1 kHz (<1 kHz optional) ≥1 MHz ≥1 MHz  
Input Level @ 800 nm >5 mW  
Spectrometer Head     
Spectral Range2 550–1050 nm  
Resolution 1.5 nm  
Input Options Free space or via fiber  
PC Interface     
Pulse Duration Evaluation 5–150 fs (5–350 fs optional)  
Hardware Requirements (computer not included) Computer with DVD ROM drive; 2x USB port (minimum 2.0); 1 GB RAM
1.5 GB hard disk space; minimum resolution 1024 x 768 px
Software Requirements Microsoft® Windows® 7, Vista® or XP  

1. Due to our continuous product improvements, specifications are subject to change without notice.
2. Standard version. For other wavelengths, please contact Spectra-Physics.
3. For measurement in focus. Minimum working distance 150 µm.

Femtometer Dimensions

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