Terahertz frequency combs exploiting an on-chip, solution-processed, graphene-quantum cascade laser coupled-cavity
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The ability to engineer quantum-cascade-lasers (QCLs) with ultrabroad gain spectra, and with a full compensation of the group velocity dispersion, at terahertz (THz) frequencies, is key for devising monolithic and miniaturized optical frequency-comb-synthesizers (FCSs) in the far-infrared. In THz QCLs four-wave mixing, driven by intrinsic third-order susceptibility of the intersubband gain medium, self-locks the optical modes in phase, allowing stable comb operation, albeit over a restricted dynamic range (∼20% of the laser operational range). Here, we engineer miniaturized THz FCSs, comprising a heterogeneous THz QCL, integrated with a tightly coupled, on-chip, solution-processed, graphene saturable-absorber reflector that preserves phase-coherence between lasing modes, even when four-wave mixing no longer provides dispersion compensation. This enables a high-power (8 mW) FCS with over 90 optical modes, through 55% of the laser operational range. We also achieve stable injection-locking, paving the way to a number of key applications, including high-precision tunable broadband-spectroscopy and quantum-metrology.
Date Issued
2020-12-16
Date Acceptance
2020-12-01
Citation
ACS Photonics, 2020, 7 (12), pp.3489-3498
ISSN
2330-4022
Publisher
American Chemical Society
Start Page
3489
End Page
3498
Journal / Book Title
ACS Photonics
Volume
7
Issue
12
Copyright Statement
© 2020 American Chemical Society. This is an open access article published under a Creative Commons Non-Commercial NoDerivative Works (CC-BY-NC-ND) Attribution License, which permits copying andredistribution of the article, and creation of adaptations, all for non-commercial purposes.
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/P02534X/2
Subjects
Science & Technology
Technology
Physical Sciences
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Optics
Physics, Applied
Physics, Condensed Matter
Science & Technology - Other Topics
Materials Science
Physics
nanoengineered devices
integrated nanostructures
graphene
saturable absorbers
semiconductor heterostucture lasers
frequency combs
INJECTION-LOCKING
ULTRAFAST
RANGE
0205 Optical Physics
0206 Quantum Physics
0906 Electrical and Electronic Engineering
Publication Status
Published
Date Publish Online
2020-12-03