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Title: Large tuning of narrow-beam terahertz plasmonic lasers operating at 78 K

A new tuning mechanism is demonstrated for single-mode metal-clad plasmonic lasers, in which the refractive-index of the laser’s surrounding medium affects the resonant-cavity mode in the same vein as the refractive-index of gain medium inside the cavity. Reversible, continuous, and mode-hop-free tuning of ~57 GHz is realized for single-mode narrow-beam terahertz plasmonic quantum-cascade lasers (QCLs), which is demonstrated at a much more practical temperature of 78 K. The tuning is based on post-process deposition/etching of a dielectric (silicon-dioxide) on a QCL chip that has already been soldered and wire-bonded onto a copper mount. This is a considerably larger tuning range compared to previously reported results for terahertz QCLs with directional far-field radiation patterns. The key enabling mechanism for tuning is a recently developed antenna-feedback scheme for plasmonic lasers, which leads to the generation of hybrid surface-plasmon-polaritons propagating outside the cavity of the laser with a large spatial extent. The effect of dielectric deposition on QCL’s characteristics is investigated in detail including that on maximum operating temperature, peak output power, and far-field radiation patterns. Single-lobed beam with low divergence (<7°) is maintained through the tuning range. The antenna-feedback scheme is ideally suited for modulation of plasmonic lasers and their sensing applicationsmore » due to the sensitive dependence of spectral and radiative properties of the laser on its surrounding medium.« less
 [1] ;  [1] ;  [2] ; ORCiD logo [1]
  1. Lehigh Univ., Bethlehem, PA (United States). Dept. of Electrical and Computer Engineering
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center of Integrated Nanotechnologies
Publication Date:
Report Number(s):
Journal ID: ISSN 2378-0967; 647329; TRN: US1701124
Grant/Contract Number:
AC04-94AL85000; ECCS 1351142; CMMI 1437168
Accepted Manuscript
Journal Name:
APL Photonics
Additional Journal Information:
Journal Volume: 2; Journal Issue: 2; Journal ID: ISSN 2378-0967
American Institute of Physics (AIP)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lehigh Univ., Bethlehem, PA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; quantum cascade lasers; plasmons; laser resonators; diffraction gratings; finite element methods
OSTI Identifier: