Frequently Asked Questions
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1) What is pulse shaping? Femtosecond pulse shaping refers to a variety of techniques that modify the time and/or frequency profiles of an ultrashort laser pulse. These changes can have useful effects on laser induced processes.
2) Why would someone want to shape ultrashort pulses? Modifying temporal or spectral domain of an ultrashort pulse can be desirable for many reasons: shortening the pulse duration, lengthening the pulse duration, manipulating the amplitude (spectrum) to obtain a desirable profile, manipulating the phase to coherently control non-linear processes. Pulse shaping opens an important dimension of control for ultrashort laser pulses.
3) How can ultrashort pulses be shaped? They can be shaped in the time or in the frequency domain.
4) What is MIIPS? Multiphoton Intrapulse Interference Phase Scan is a single-beam method to characterize femtosecond pulses. It combines iterative spectral phase characterization and compensation using a pulse shaper. In MIIPS, a known phase function is used to extract the unknown phase distortions. MIIPS is extremely accurate and does not require autocorrelation or interferometric analysis.
5) What are the benefits of MIIPS-based devices over other commercially available pulse shapers? MIIPS-based pulse shapers, like the Silhouette from Coherent, provide accurate built-in pulse characterization, therefore, they produce accurate arbitrary pulse shaping AND fast pulse compression.
6) Can a MIIPS-enabled pulse shaper help an existing femtosecond laser system produce shorter pulses, with greater reliability and stability? By measuring and automatically compensating for phase distortions, MIIPS will achieve the shortest pulses (transform limited) using any femtosecond laser system.
7) How long does it take to measure femtosecond pulses using MIIPS? Quick scan takes 15-20s. For more demanding applications the fine setting takes 4 minutes.
8) Should I build a pulse shaper or should I buy one? There are two aspects to consider; hardware and software. The optical setup is not too complex, but knowing all the parameters to achieve the desired optical resolution is very important. Note that a shaper by itself is like a computer without software. Writing software that calibrates the shaper is not easy. Writing software that can measure and compress pulses like MIIPS is definitively challenging. The time it would take to program a system to be accurate and user friendly is extensive and not cost effective. We recommend purchasing the commercial system that is ready to work out of the box, comes with a user manual and has great support.
9) Why not use a prism pair or a grating pair for compression? Prism or grating pairs can compensate for second order dispersion. Ultrashort pulses carry higher order phase distortions that can not be corrected by prism or grating pairs.
10) How does MIIPS compare to the other ultrashort pulse characterization methods? MIIPS, unlike other methods, provides additionally automatic phase compensation. Statistical errors (adapted from the reference) are:
11) Is MIIPS compatible with high intensity femtosecond lasers? We have shown that the MIIPS pulse shaper can be placed between the oscillator and the amplifier. This setup has been demonstrated with a 2.5 mJ/pulse system. There is no reason why the same idea cannot be extended to any power level.
12) Can MIIPS be used for industrial applications? MIIPS was designed for automated femtosecond laser optimization, making it ideal for all industrial applications. If you have an application in mind, contact us. We are sure you will not find another product that can provide the level of optimization and reproducible performance that MIIPS can.