A. Laramée

10 mJ 5-cycle pulses at 1.8 μm through optical parametric amplification

We report the generation of 10 mJ, 5-cycle pulses at 1.8 μm (30 fs) at 100 Hz repetition rate using an optical parametric amplifier pumped by a high energy Titanium-Sapphire laser system (total energy of 23 mJ for Signal and Idler). This is the highest reported peak power (0.33 TW) in the infrared spectral range. This high-energy long wavelength laser source is well suited for driving various nonlinear optical phenomena such as high harmonic generation for high flux ultrafast soft X-ray pulses.

2.5 TW, two-cycle IR laser pulses via frequency domain optical parametric amplification

Broadband optical parametric amplification in the IR region has reached a new milestone through the use of a non-collinear Frequency domain Optical Parametric Amplification system. We report a laser source delivering 11.6 fs pulses with 30 mJ of energy at a central wavelength of 1.8 μm at 10 Hz repetition rate corresponding to a peak power of 2.5 TW. The peak power scaling is accompanied by a pulse shortening of about 20% upon amplification due to the spectral reshaping with higher gain in the spectral wings. This source paves the way for high flux soft X-ray pulses and IR-driven laser wakefield acceleration.

Laser stimulated plasma-induced luminescence for on-air material analysis

In this work, we present a method for performing analysis of the chemical composition and optical properties of materials using In-Air Plasma-Induced Luminescence. This is achieved by interaction of a focused high-energy laser with air, an interaction that produces a sub-millimetric plasma. The energetic electrons generated and accelerated in the plasma at energies higher than 5 keV reach the target surface of the sample to be analyzed, causing luminescence emission and plasmonic resonance. Each material is characterized by different chemical and optical properties that can be determined with the above-described technique. As such, our method allows obtaining an exact analysis of the sample, covering surfaces in the range of tens of mm2, in only a few minutes. We show that the acquired information with our method is identical to what obtained with more sophisticated methods, such as SEM-cathodoluminescence and photoluminescence.

Intense THz-coherent transition radiation from laser solid plasma interaction

We investigate intense broadband terahertz radiation generation based the interaction of high intensity ultrashort laser with solid plasma. THz pulse with electric field of hundreds of MV/cm are generated using laser with intensity of about 1018 W/cm2. Theoretical model, simulations agree well with experiments, and reveal that the THz radiation is coherent transition radiation by hot electrons produced in laser-plasma interaction. We have studied both planar and nanorod array targets, latter of which efficiently enhance the intensity and directionality of the THz source.

Frequency domain optical parametric amplification

General restrictions arising from gain-narrowing and phase-matching are circumvented by employing parametric amplification in the frequency rather than the time domain. Frequency-domain OPA has been used for amplifying few-cycle pulses and for high gain amplification.