Terahertz quantum cascade lasers based on two-dimensional photonic crystal resonators

Abstract

We demonstrate high spectral control from surface emitting THz Quantum Cascade Lasers based on a two-dimensional photonic crystal cavity. The perforated top metallic contact acts as an in plane resonator in a tight double-metal plasmonic waveguide providing a strong optical feedback without needing three-dimensional cavity features. The optical far-field patterns do not exhibit the expected symmetry and the shape of the cavity mode. The difference is attributed to a metal surface plasmon mediated light outcoupling mechanism also responsible for the relatively low extraction efficiency.

Coupled Mode Theory of Photonic Crystal Lasers

“…The photonic crystal structures lasing wavelengths span from terahertz (Chassagneux et al (2009) ;Sirigu et al (2008)), through infrared (Kim et al (2006)) to visible (Lu et al (2008); Zhang et al (2006)). 14 www.intechopen.com…”

THz and sub‐THz quantum cascade lasers

“…Traditional dielectric waveguides are unpractical because of the large cladding thickness required; solutions relying on the use of metallic layers supporting surface plasmon modes have been developed for an efficient guiding of the THz radiation Two principal schemes have been developed to provide efficient optical resonators for THz QCLs: single plasmon and double metal waveguides. Based on these two main waveguides configurations, more refined structures have been realized where photonic bandstructure engineering is implemented [31][32][33][34][35].…”

“…16. The threshold current density drops by a factor of five when ω c > ΔE 31 . This is not true for sample A2664 for which the strong confinement limit is set at B = m * ΔE31 e ≈ 14.5 T. The threshold in the strong confinement region reduces to values below 5 A/cm 2 , which are the lowest measured for any intersubband laser.…”

Surface-emitting terahertz quantum cascade lasers with continuous-wave power in the tens of milliwatt range

“…11 In this Letter, we investigate device architectures that can provide high (tens of milliwatt) CW output powers. Specifically, we aim to obtain significantly higher powers than have been observed to date using either 2D photonic crystals [12][13][14][15][16][17][18] or second-order DFB gratings. [19][20][21][22][23][24] Recently, we have demonstrated surface-emitting THz QCLs based on graded photonic heterostructure (GPH) resonators (shown schematically in Fig.…”