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Pump-probe Spectroscopy

Time-resolved measurements with up to femtosecond resolution

  • Time resolved spectroscopy
  • Multi-beam configuration
  • Coherent, synchronized beams
  • Ultrashort pulses < 15 fs
  • Wavelength coverage 488 nm - 2200 nm
  • Control of pulse properties

Pump-probe spectroscopy was honored with the 1999 nobel prize awarded to Ahmed Zewail. In femtochemistry and material research, ultrafast dynamics of molecules are visualized with snap shots delivered by femtosecond and picosecond lasers: in a first step, a laser pulse pumps the population of a molecule into an excited state. The state itself exhibits relaxation dynamics in the femtosecond or picosecond time regime. In a second step, another laser pulse probes the population in the excited state at different time delays in respect to the excitation. During the last decade the focus shifted from pure observation to active control and manipulation of dynamical reactions: So-called coherent control methods are employed. These are based on controlling the spectral phase and/or amplitude of the laser pulses by using spatial light modulators (SLMs). The excitation with shaped laser pulses allows for the investigation of quantum interference phenomena like the specific break of chemical bonds in molecules and other ultrafast processes in the investigated material.

TOPTICA contributes to this field with newest fiber technology which is outstanding in performance and versatility. A single laser system can be equipped with various outputs that are intrinsically optically synchronized down to the attosecond level. All of these can be configured individually to satisfy the experimental needs: Pulse durations as short as 15 fs or broad tuning ranges of 490 nm to 700 nm, 850 nm to 1000 nm or 980 nm to 2200 nm are available. Within the third generation of TOPTICA’s ultrafast fiber lasers a novel, versatile toolbox is available to realize even more advanced pump-probe spectroscopy schemes. The FemtoFiber dichro bioMP outputs two different wavelength simultaneously (1050/780 nm at 150 fs), while the system can control the relative time delay of both colors and the GDD as well. Additionally the laser is capable of modulating the intensity of both colors by tuning the transmission of the fast internal AOM’s to adjust for the correct excitation power.