Carrier-envelope-phase-dependent below-threshold harmonic generation in few-cycle mid-infrared laser fields.

We theoretically study the dependence of below-threshold harmonic generation (BTHG) of atoms on the carrier-envelope phase (CEP) driven by few-cycle mid-infrared laser pulses. The BTHG spectra can be accurately and efficiently calculated by solving the three-dimensional time-dependent Schrödinger equation using the time-dependent generalized pseudospectral method. We present the BTHG spectra as a function of the laser-field CEP.