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Title: Metasurface quantum-cascade laser with electrically switchable polarization

Dynamic control of a laser’s output polarization state is desirable for applications in polarization sensitive imaging, spectroscopy, and ellipsometry. Using external elements to control the polarization state is a common approach. Less common and more challenging is directly switching the polarization state of a laser, which, however, has the potential to provide high switching speeds, compactness, and power efficiency. Here, we demonstrate a new approach to achieve direct and electrically controlled polarization switching of a semiconductor laser. This is enabled by integrating a polarization-sensitive metasurface with a semiconductor gain medium to selectively amplify a cavity mode with the designed polarization state, therefore leading to an output in the designed polarization. Here, the demonstration is for a terahertz quantum-cascade laser, which exhibits electrically controlled switching between two linear polarizations separated by 80°, while maintaining an excellent beam with a narrow divergence of ~3°×3° and a single-mode operation fixed at ~3.4 THz, combined with a peak power as high as 93 mW at a temperature of 77 K. The polarization-sensitive metasurface is composed of two interleaved arrays of surface-emitting antennas, all of which are loaded with quantum-cascade gain materials. Each array is designed to resonantly interact with one specific polarization; when electricalmore » bias is selectively applied to the gain material in one array, selective amplification of one polarization occurs. The amplifying metasurface is used along with an output coupler reflector to build a vertical-external-cavity surface-emitting laser whose output polarization state can be switched solely electrically. In conclusion, this work demonstrates the potential of exploiting amplifying polarization-sensitive metasurfaces to create lasers with desirable polarization states—a concept which is applicable beyond the terahertz and can potentially be applied to shorter wavelengths.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1]
  1. Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering; Univ. of California, Los Angeles, CA (United States). California NanoSystems Inst.
  2. Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center of Integrated Nanotechnologies
Publication Date:
Report Number(s):
SAND-2016-12371J
Journal ID: ISSN 2334-2536; 649740
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Optica
Additional Journal Information:
Journal Volume: 4; Journal Issue: 4; Journal ID: ISSN 2334-2536
Publisher:
Optical Society of America
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION
OSTI Identifier:
1360798