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Title: Metasurface quantum-cascade laser with electrically switchable polarization

Abstract

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:
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)
OSTI Identifier:
1360798
Report Number(s):
SAND-2016-12371J
Journal ID: ISSN 2334-2536; 649740
Grant/Contract Number:
AC04-94AL85000
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Optica
Additional Journal Information:
Journal Volume: 4; Journal Issue: 4; Journal ID: ISSN 2334-2536
Publisher:
Optical Society of America
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Xu, Luyao, Chen, Daguan, Curwen, Christopher A., Memarian, Mohammad, Reno, John L., Itoh, Tatsuo, and Williams, Benjamin S.. Metasurface quantum-cascade laser with electrically switchable polarization. United States: N. p., 2017. Web. doi:10.1364/OPTICA.4.000468.
Xu, Luyao, Chen, Daguan, Curwen, Christopher A., Memarian, Mohammad, Reno, John L., Itoh, Tatsuo, & Williams, Benjamin S.. Metasurface quantum-cascade laser with electrically switchable polarization. United States. doi:10.1364/OPTICA.4.000468.
Xu, Luyao, Chen, Daguan, Curwen, Christopher A., Memarian, Mohammad, Reno, John L., Itoh, Tatsuo, and Williams, Benjamin S.. Thu . "Metasurface quantum-cascade laser with electrically switchable polarization". United States. doi:10.1364/OPTICA.4.000468. https://www.osti.gov/servlets/purl/1360798.
@article{osti_1360798,
title = {Metasurface quantum-cascade laser with electrically switchable polarization},
author = {Xu, Luyao and Chen, Daguan and Curwen, Christopher A. and Memarian, Mohammad and Reno, John L. and Itoh, Tatsuo and Williams, Benjamin S.},
abstractNote = {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 electrical 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.},
doi = {10.1364/OPTICA.4.000468},
journal = {Optica},
number = 4,
volume = 4,
place = {United States},
year = {Thu Apr 20 00:00:00 EDT 2017},
month = {Thu Apr 20 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 5works
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  • A terahertz vertical-external-cavity surface-emitting-laser (VECSEL) is demonstrated using an active focusing reflectarray metasurface based on quantum-cascade gain material. The focusing effect enables a hemispherical cavity with flat optics, which exhibits higher geometric stability than a plano-plano cavity and a directive and circular near-diffraction limited Gaussian beam with M 2 beam parameter as low as 1.3 and brightness of 1.86 × 10 6 Wsr –1m –2. As a result, this work initiates the potential of leveraging inhomogeneous metasurface and reflectarray designs to achieve high-power and high-brightness terahertz quantum-cascade VECSELs.
  • Light emitted from single-mode semiconductor lasers generally has large divergence angles, and high numerical aperture lenses are required for beam collimation. Visible and near infrared lasers are collimated using aspheric glass or plastic lenses, yet collimation of mid-infrared quantum cascade lasers typically requires more costly aspheric lenses made of germanium, chalcogenide compounds, or other infrared-transparent materials. We report mid-infrared dielectric metasurface flat lenses that efficiently collimate the output beam of single-mode quantum cascade lasers. The metasurface lenses are composed of amorphous silicon posts on a flat sapphire substrate and can be fabricated at low cost using a single step conventionalmore » UV binary lithography. Mid-infrared radiation from a 4.8 μm distributed-feedback quantum cascade laser is collimated using a polarization insensitive metasurface lens with 0.86 numerical aperture and 79% transmission efficiency. The collimated beam has a half divergence angle of 0.36° and beam quality factor of M² =1.02.« less
  • A terahertz quantum-cascade (QC) vertical-external-cavity surface-emitting-laser (VECSEL) is demonstrated with over 5 mW power in continuous-wave and single-mode operation above 77 K, in combination with a near-Gaussian beam pattern with full-width half-max divergence as narrow as ~5° × 5°, with no evidence of thermal lensing. This is realized by creating an intra-cryostat VECSEL cavity to reduce the cavity loss and designing an active focusing metasurface reflector with low power dissipation for efficient heat removal. Compared with a conventional quantumcascade laser based on a metal-metal waveguide, the intra-cryostat QC-VECSEL exhibits significant improvements in both output power level and beam pattern. Also,more » the intra-cryostat configuration newly allows evaluation of QC-VECSEL operation vs. temperature, showing a maximum pulsed mode operating temperature of 129 K. While the threshold current density in the QC-VECSEL is worse in comparison to a conventional edge-emitting metal-metal waveguide QClaser, the beam quality, slope efficiency, maximum power, and thermal resistance are all significantly improved.« less