Highly Efficient Terahertz Generation Using 3D Dirac Semimetals

Abstract

It is shown that three-dimensional Dirac semimetals are promising candidates for highly efficient optical-to-terahertz conversion due to their extreme optical nonlinearities. In particular, it is predicted that the conversion efficiency of Cd 3 As 2 exceeds typical materials like LiNbO 3 by >5000 times over nanoscale propagation distances. Studies show that even when no restrictions are placed on propagation distance, Cd 3 As 2 still outperforms LiNbO 3 in efficiency by >10 times. The results indicate that by tuning the Fermi energy, Pauli blocking can be leveraged to realize a step-like efficiency increase in the optical-to-terahertz conversion process. It is found that large optical-to-terahertz conversion efficiencies persists over a wide range of input frequencies, input field strengths, Fermi energies, and temperatures. These results could pave the way to the development of ultrathin-film terahertz sources for compact terahertz technologies.

Table-Top Tunable Chiral Photonic Emitter

“…As a result, emissions observed along the ẑ direction become a pivotal metric for deducing the Weyl nodes' separation, b. Besides, since the nonlinearity of the emitted harmonics is proportional to the Fermi velocities [58] as shown in Eqs. (2)(3)(4), the Fermi velocities of WSMs can be retrieved by obtaining the amplitude of a given harmonic.…”

High-harmonic generation in semi-Dirac and Weyl semimetals with broken time-reversal symmetry: exploring the case of multiple semi-Dirac points

“…The investigation of high harmonic generation (HHG) in condensed matter systems has garnered considerable attention, driven by its potential applications in ultrafast optics [1][2][3][4][5][6][7][8] and its role as a characterization method. 9-16 HHG's efficiency in Dirac (DSMs) and Weyl semimetals (WSMs) is attributed to their gapless nature and linear energy dispersion, [16][17][18][19][20][21][22][23][24] along with their high carrier mobilities. [25][26][27][28][29] In WSMs, the linear anomalous response, i.e.…”

Narrowband, Angle-Tunable, Helicity-Dependent Terahertz Emission from Nanowires of the Topological Dirac Semimetal Cd3As2

“…Interest is now extended to the THz range, where its nonlinearity has been probed through high-harmonic generation via THz-pump THz-probe spectroscopy, , and intense THz pulses have generated Raman phonon coherences that can drive topological phase transitions . Alongside these, theoretical studies have predicted an enhancement in optical-to-terahertz conversion efficiency in Cd 3 As 2 that is 5000 times higher than the current state of the art for high-energy narrowband THz emissionlithium niobate . However, this enhancement has yet to be realized experimentally.…”