Intense terahertz generation in two-color laser filamentation: energy scaling with terawatt laser systems

Abstract

We investigate high-power terahertz (THz) generation in two-color laser filamentation using terawatt (TW) lasers including a 0.5 TW, 1 kHz system, as well as 2 and 30 TW systems both operating at 10 Hz. With these lasers, we study the macroscopic effect in filamentation that governs THz output energy yields and radiation profiles in the far field. We also characterize the radiation spectra at a broad range of frequencies covering radio–micro-waves to infrared frequencies. In particular, our 1 kHz THz source can provide high-energy (>1 μ J), high average power (>1 mW), intense (>1 MV cm ^−1 ) and broadband (0.01–60 THz) THz radiation via two-color filamentation in air. Based on our scaling law, an ∼30 TW laser can produce >0.1 mJ of THz radiation with multi-gigawatt peak power in ∼1.5 m long filamentation.