Terahertz amplification and lasing in pump-probe experiments with hyperbolic polaritons in h-BN

arXiv (Cornell University)

Abstract

We discuss terahertz pump-probe experiments in hBN from the perspective of Floquet optical materials and photonic time crystals. Anisotropic nature of this material results in a large separation of frequencies of in-plane and out-of-plane optical phonons and leads to several branches of phonon-polariton excitations. We consider a slab of finite thickness pumped at the frequency of middle polaritons, around 25 THz. We theoretically analyze properties of the pump induced state and identify several interesting features, including possible light amplification and parametric instability at 2 THz. We relate these features to resonant pair scattering processes of polaritons excited by the pump pulse. We show that amplification/instability frequency ranges depend on both the pump intensity and the slab thickness. We point out that this setup can be used utilized to strongly enhance optical nonlinearities at terahertz frequencies. Richness and tunability of this system suggests that it holds promise for practical applications in terahertz technology.

Authors 4

1. Khachatur G. Nazaryan

   Massachusetts Institute of Technology

   Affiliation as printed

   Department of Physics , Massachusetts Institute of Technology , Cambridge , MA 02139

2. Ivan Ridkokasha Aachen Instituut-Lorentz

   Leiden University

   Affiliation as printed

   Instituut-Lorentz , Universiteit Leiden , P.O. Box 9506 , 2300 RA Leiden , The Netherlands

3. Marios H. Michael

   Max Planck Institute for the Structure and Dynamics of Matter

   Affiliation as printed

   Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chausse 149 , 22761 Hamburg , Germany

4. Eugene Demler

   ETH Zurich · Institute for Theoretical Physics

   Affiliation as printed

   Institute for Theoretical Physics , Wolfgang Pauli Str. 27 , ETH Zurich , 8093 Zurich , Switzerland