Demonstration of sub-luminal propagation of single-cycle terahertz pulses for particle acceleration.

ABSTRACT: The sub-luminal phase velocity of electromagnetic waves in free space is generally unobtainable, being closely linked to forbidden faster than light group velocities. The requirement of sub-luminal phase-velocity in laser-driven particle acceleration schemes imposes a limit on the total acceleration achievable in free space, and necessitates the use of dispersive structures or waveguides for extending the field-particle interaction. We demonstrate a travelling source approach that overcomes the sub-luminal propagation limits. The approach exploits ultrafast optical sources with slow group velocity propagation, and a group-to-phase front conversion through nonlinear optical interaction. The concept is demonstrated with two terahertz generation processes, nonlinear optical rectification and

SUBMITTER: Walsh DA 

PROVIDER: S-EPMC5583180 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature