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 µJ), 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 multigigawatt peak power in ∼1.5 m long filamentation.

THz radiation by amplitude-modulated self-focused Gaussian laser beam in ripple density plasma

“…This kind of density ripple can be created by different techniques (Hazra et al, 2004;Pai et al, 2005;Layer et al 2007;Liu et al, 2008). The laser propagates in the z-direction and polarized in the x-direction.…”

“…Experimental studies have also been done to generate intense THz pulses using two color laser filamentation using TW lasers. High-energy (>1 μJ), high average power (>1 mW), intensity (>1 MV cm −1 ), and broadband (0.01-60 THz) THz via two color filamentations have been reported (Oh et al, 2013). There are several techniques available for the study of self-focusing in the plasma.…”

Aligned copper nanorod arrays for highly efficient generation of intense ultra-broadband THz pulses

“…Stimulated by such applications, the generation of intense THz pulses has recently been the subject of great interest, and several table-top techniques have been studied in detail1011. For example, optical rectification sources and THz generation from air plasma1213 have been the subject of many extensive efforts to scale up both THz peak electric field and energy10. THz pulses with more than 100 MV/cm peak electric field have been demonstrated by difference-frequency mixing of two parametrically amplified pulses14.…”

Effect of two-color laser pulse intensity ratio on intense terahertz generation

“…Conventional THz sources were usually achieved by semiconductor photoconductive switches [11,12] or optical rectification in nonlinear crystals [13], while the THz field intensity by the two schemes is relatively low and its spectral range is narrow. Recently, as an alternative approach, two-color laser field has been proposed to generate the intense and broadband THz pulse [14][15][16]. In this two-color scheme, a fundamental femtosecond laser field combining with its second harmonic field are focused in air to generate gaseous plasma, and an intense THz pulse can be irradiated in the forward direction.…”