Experimental analysis of phase-locked harmonic generation in absorptive materials: application to TW laser beam characterization
Abstract
We propose to conduct experimental investigations highlighting the dependence of the phase locked component of the second and third harmonic generation in absorptive materials on the We propose an application of this effect to the TW laser beam spatial profile characterization. When a beam is tuned in the transparency region of a generic nonlinear crystal, two components of second harmonic beams are generated; the well-known homogeneous component that travels with the group velocity and experiment the absorption given by material dispersion, and the inhomogeneous component it is trapped and dragged along in the same direction as the pump. These phase-locked harmonic component propagates into the material with the same phase and group velocities and absorption coefficients as the fundamental beam, regardless of the dispersion at the harmonic frequency. This behavior was experimentally validated first by the measurement of the two different SH components in transparent materials, and latter, it has been proved that the phase and group velocity locking leads to the inhibition of linear absorption when the pump is tuned to a transparency region. In spite of these theoretical and experimental studies, there is still a relative lack of knowledge regarding the dynamics of the short pulses generated in the mismatched regime where the phase locked components can be observed. The availability of laser sources with ever decreasing pulse durations and huge pick power make necessary a systematic investigation of the phase locked SH and the possible applications. Objective 1 Study of the angular dependence of the phase-locked SH and TH components Objective 2. Polarization dependence of the phase-locked harmonic components Objective 3. Measurement of the harmonic phase-locked components in reflection Objective 4. Spatial distribution of the harmonic phase-locked components
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 22, 2018
- Source ID
- W911NF1810259
Entities
People
- Crina Cojocaru
Organizations
- Army Contracting Command
- Polytechnic University of Catalonia
- United States Army