Tolk's group


Free Electron Laser Lab

Although the Vanderbilt Free Electron Laser is no longer active, we maintain a lab in the facility with multiple ultra-high vacuum chambers, including Low-energy electron difffaction (LEED) and quadrapole mass spectrometry (QMS) capabilities. Also at the FEL is a 9 T superconducting magnet with four optical windows.

Spectra-Physics ultrafast laser system

includes a Ti:Sapphire oscillator with a cw pumping laser (MaiTai) and a 45 W pulsed Nd:YLF laser (Empower) to pump a regenerative amplifier (Spitfire Ace) with 6.5 W output power and a variable repetition rate (from 1 Hz to 10 kHz with a step of 1 Hz). This system is state-of-the art among high-energy ultrafast systems with pulse duration (bandwidth) of 100 fs (12 nm). The Spitfire Ace-PA-401K provides low noise, long-term power and temperature stability, day-to-day reproducibility. It is fully compatible with our existing two Optical Parametric Amplifiers (Quantronix/ Light Conversion TOPAS). The stable spectral range achievable extends from ~ 200 nm to > 20 µm (roughly 6.0 eV – 0.06 eV). The system is designed so that such wavelength selection is operationally readily facilitated.

To upgrade the experimental system, two existing optical parametric amplifiers (TOPAS) were adapted to the new laser system. A telescope to limit a diameter of the beam from amplifier was built.

TITAN / TOPAS amplification system:

  • Photon Energy Range: 0.06-6 eV
  • Pulse Width: 150fs or 3.5ps
  • Pulse Energy: 10uJ
  • Repetition Rate: 1 KHz
  • Three-color experiments with coherent pulses



Outer Laser Lab

Ti:Sapphire Laser

Inner Laser Lab

Ti:Saphire Laser