Circularly polarized sub-1.5 cycle laser pulses at 1.8 μm.

The generation of intense carrier-envelope-phase-stabilized sub-1.5 cycle circularly polarized pulses at 1.8 μm is reported. After changing the polarization of the pulses produced by an optical parameter amplifier to circular, selected nonlinear medium parameters are found to be able to expand the spectrum to supercontinuum (1,300-2,100 nm) with a extremely high transmittance (>65 %). Using such laser pulses, polarization control of terahertz emission is demonstrated. [ABSTRACT FROM AUTHOR]