High Intensity Laser Technology

Dan Dakin, UD undergraduate alumni aligning the terawatt laser system in Walker Lab.
Renovated lab of Prof. Walker, thanks to diligent work of all graduate and undergraduate students, is in 014A Sharp Lab.

The optical technology part of the program currently involves the development of compact terawatt amplifier with an industrial partner ALTOS, Inc. The goal of this project is to build a laser system at the level of 1 microcent per watt of peak power. This project is being funded by the Delaware Research Partnership (DRP). The DRP encourages industrial partnerships with the University of Delaware to best meet the needs of both parties and serve the community. The laser (shown on the right) is composed of two 10 Hz repetition rate, unstable oscillator pump lasers that are frequency doubled in KTP and used to pump a 4-pass bowtie Ti:sapphire amplifier. The system currently operates at a conversion efficiency of about 35% green to red and produces, at maximum power, pulses with 0.28 J of energy. The final goal of this system is to be able to amplify light from the 5 mJ level to 300 mJ level across a bandwidth of about 20 THz.

Experimental studies of ultrahigh intensity light-matter interactions are also underway in the laboratory. Currently, we are interested in measurements of how very intense light interacts with atoms. As atoms are exposed to the laser fields, we observe the products from this excitation process. The chamber used to measure the ions from the interaction is shown to the right. This chamber measures the interaction of light with single atoms in a vacuum less than one-trillionth of an atmosphere (<10-13). The intensity of the light in the focus of the laser beam is about 10,000 trillion W/cm2.

The experimental apparatus has resulted from graduate and undergraduate students working to gain insights into the new and exciting physics. The exploratory research experience is a unique educational opportunity relevant to many careers including optical communications technology and fundamental studies in atomic, molecular, optical, or plasma physics. Skills learned in the program range from machining and computer aided drafting and design (CADD) to quantum mechanics and numerical calculations of the Schrodinger equation.

Research Projects and Technology:

  • Atom interactions with ultraintense laser fields: The interaction of atoms with laser intensities from 1017 W/cm2 to 1019 W/cm2 gives rise to very high-energy particles and radiation. The electrons ripped off the atom by ultra-intense lasers will have kinetic energies exceeding their rest mass. They will travel near the speed of light and have millions of electron volts of energy. The dynamics are relativistic and the physics is only now beginning to be understood.
  • Laser technology for high power, ultrafast lasers: Intense laser interactions and measurements of the fast dynamics for processes in atoms and molecules require lasers that can generate very short pulses of light with high peak intensities. This research laboratory is also involved in laser and optical technology development with some of the highest peak power lasers in the world. These efforts are aimed to meet the scientific demands for high repetition rate, high peak power, ultrashort pulse duration light sources with wavelengths between 300 eV and 0.5 eV. Recent advances in beam shaping technology allow amplification to the terawatt peak power level with a spatial beam profile better than what is available with many 5 milliwatt HeNe lasers.
  • The research in high intensity laser physics has significant overlap with commercial interests. These range from laser induced breakdown spectroscopy (LIBS) to high data rate communications in optical fibers.

Research Highlights: