- Avoids Sensitive Calibration
- Direct Reconstruction, No Iterative Search Algorithm Required
- 50 Attosecond Phase Delay Precision
- Dispersion Free
- Octave-Spanning Bandwidth
- Fundamental and Up-Converted Spectrum Measured in Same Device
- Fully Automated
- Guide Laser for Easy Set Up
Thorlabs' solution for measuring sub-two-cycle pulses is Two-Dimensional Spectral Shearing Interferometry (2DSI). 2DSI measures an ultrashort pulse envelope by interfering neighboring spectral components. This technique was developed in close collaboration with MIT.
2DSI overcomes certain disadvantages in other femtosecond pulse measurement techniques by encoding the spectral group delay in the spectrum of a single nonlinearly transformed pulse, rather than two. This avoids the need to calibrate the delay between two pulses to high precision, a potential complication with other techniques for few-cycle pulses and below. In addition, the interferogram produced by 2DSI is a direct representation of the spectral group delay of the pulse, allowing for reconstruction of the pulse shape without the need for iterative search algorithms.
This allows 2DSI to accurately measure the spectral group delay of pulses with time-bandwidth products in excess of 20, precisely resolving all pulse features, such as weak satellite pulses, which other techniques can miss. The 2DSI geometry also inherently avoids having the pulse pass through any dispersive materials and uses type II up-conversion with a phase-matching bandwidth of nearly an octave.
Thorlabs' 2DSI automates the measurement process so that the only user intervention required is the initial alignment, which is made simple by a green counter-propagating alignment laser. The mechanical setup is based on our proven flexure stage design for all critical components. Long-term hands-off operation was one of the major design goals. A high-quality, high-dynamic-range spectrometer allows for simultaneous measurement of both the 2DSI inteferogram and fundamental spectrum.
|Wavelength||650 - 1000 nm||650 - 1100 nm|
|Pulse Width*||4 - 50 fs|
|Time-Bandwidth Product||>20 (Max)|
|Spectral Phase Precision||50 attoseconds|
|Pulse Energy||1 nJ - 1 µJ|
|Refresh Rate||Up to 10 Hz|
|Dimensions||326 mm x 240 mm (12.85" x 9.45")|
*Longer pulse widths are available upon request.