Center for Quantum Devices - Most Downloaded Journal Articles

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4.	Room temperature terahertz semiconductor frequency comb Quanyong Lu, Feihu Wang, Donghai Wu, Steven Slivken & Manijeh Razeghi Nature Communications 10, 2403-- June 3, 2019 ...[Visit Journal] A terahertz (THz) frequency comb capable of high-resolution measurement will significantly advance THz technology application in spectroscopy, metrology and sensing. The recently developed cryogenic-cooled THz quantum cascade laser (QCL) comb has exhibited great potentials with high power and broadband spectrum. Here, we report a room temperature THz harmonic frequency comb in 2.2 to 3.3 THz based on difference-frequency generation from a mid-IR QCL. The THz comb is intracavity generated via down-converting a mid-IR comb with an integrated mid-IR single mode based on distributed-feedback grating without using external optical elements. The grating Bragg wavelength is largely detuned from the gain peak to suppress the grating dispersion and support the comb operation in the high gain spectral range. Multiheterodyne spectroscopy with multiple equally spaced lines by beating it with a reference Fabry-Pérot comb confirms the THz comb operation. This type of THz comb will find applications to room temperature chip-based THz spectroscopy. [reprint (PDF)]
4.	High performance photodiodes based on InAs/InAsSb type-II superlattices for very long wavelength infrared detection A. M. Hoang, G. Chen, R. Chevallier, A. Haddadi, and M. Razeghi Appl. Phys. Lett. 104, 251105 (2014)-- June 23, 2014 ...[Visit Journal] Very long wavelength infrared photodetectors based on InAs/InAsSb Type-II superlattices are demonstrated on GaSb substrate. A heterostructure photodiode was grown with 50% cut-off wavelength of 14.6 μm. At 77 K, the photodiode exhibited a peak responsivity of 4.8 A/W, corresponding to a quantum efficiency of 46% at −300 mV bias voltage from front side illumination without antireflective coating. With the dark current density of 0.7 A/cm², it provided a specific detectivity of 1.4 × 10¹⁰ Jones. The device performance was investigated as a function of operating temperature, revealing a very stable optical response and a background limited performance below 50 K. [reprint (PDF)]
4.	High Power Mid-Infrared Quantum Cascade Lasers Grown on Si Steven Slivken, Nirajman Shrestha, and Manijeh Razeghi Photonics, vol. 9, 626 ...[Visit Journal] This article details the demonstration of a strain-balanced, InP-based mid-infrared quantum cascade laser structure that is grown directly on a Si substrate. This is facilitated by the creation of a metamorphic buffer layer that is used to convert from the lattice constant of Si (0.543 nm) to that of InP (0.587 nm). The laser geometry utilizes two top contacts in order to be compatible with future large-scale integration. Unlike previous reports, this device is capable of room temperature operation with up to 1.6 W of peak power. The emission wavelength at 293 K is 4.82 um, and the device operates in the fundamental transverse mode. [reprint (PDF)]
4.	High Power Mid-Infrared Quantum Cascade Lasers Grown on GaAs Steven Slivken and Manijeh Razeghi Photonics 2022, 9(4), 231 (COVER ARTICLE) ...[Visit Journal] The motivation behind this work is to show that InP-based intersubband lasers with high power can be realized on substrates with significant lattice mismatch. This is a primary concern for the integration of mid-infrared active optoelectronic devices on low-cost photonic platforms, such as Si. As evidence, an InP-based mid-infrared quantum cascade laser structure was grown on a GaAs substrate, which has a large (4%) lattice mismatch with respect to InP. Prior to laser core growth, a metamorphic buffer layer of InP was grown directly on a GaAs substrate to adjust the lattice constant. Wafer characterization data are given to establish general material characteristics. A simple fabrication procedure leads to lasers with high peak power (>14 W) at room temperature. These results are extremely promising for direct quantum cascade laser growth on Si substrates. [reprint (PDF)]
4.	Microstrip Array Ring FETs with 2D p-Ga2O3 Channels Grown by MOCVD Manijeh Razeghi, Junhee Lee, Lakshay Gautam, Jean-Pierre Leburton, Ferechteh H. Teherani, Pedram Khalili Amiri, Vinayak P. Dravid and Dimitris Pavlidis Photonics 2021, 8(12), 578; ...[Visit Journal] Gallium oxide (Ga2O3) thin films of various thicknesses were grown on sapphire (0001) substrates by metal organic chemical vapor deposition (MOCVD) using trimethylgallium (TMGa), high purity deionized water, and silane (SiH4) as gallium, oxygen, and silicon precursors, respectively. N2 was used as carrier gas. Hall measurements revealed that films grown with a lower VI/III ratio had a dominant p-type conduction with room temperature mobilities up to 7 cm2/Vs and carrier concentrations up to ~1020 cm−3 for thinner layers. High resolution transmission electron microscopy suggested that the layers were mainly κ phase. Microstrip field-effect transistors (FETs) were fabricated using 2D p-type Ga2O3:Si, channels. They achieved a maximum drain current of 2.19 mA and an on/off ratio as high as ~108. A phenomenological model for the p-type conduction was also presented. As the first demonstration of a p-type Ga2O3, this work represents a significant advance which is state of the art, which would allow the fabrication of p-n junction based devices which could be smaller/thinner and bring both cost (more devices/wafer and less growth time) and operating speed (due to miniaturization) advantages. Moreover, the first scaling down to 2D device channels opens the prospect of faster devices and improved heat evacuation [reprint (PDF)]
4.	Room temperature quantum cascade lasers with 22% wall plug efficiency in continuous-wave operation F. Wang, S. Slivken, D. H. Wu, and M. Razeghi Optics Express Vol. 28, Issue 12, pp. 17532-17538-- June 8, 2020 ...[Visit Journal] We report the demonstration of quantum cascade lasers (QCLs) with improved eﬃciency emitting at a wavelength of 4.9 µm in pulsed and continuous-wave(CW)operation. Based on an established design and guided by simulation, the number of QCL-emitting stages is increased in order to realize a 29.3% wall plug eﬃciency (WPE) in pulsed operation at room temperature. With proper fabrication and packaging, a 5-mm-long, 8-µm-wide QCL with a buried ridge waveguide is capable of 22% CW WPE and 5.6 W CW output power at room temperature. This corresponds to an extremely high optical density at the output facet of ∼35 MW/cm², without any damage. [reprint (PDF)]
4.	Avalanche Photodetector Based on InAs/InSb Superlattice Arash Dehzangi, Jiakai Li, Lakshay Gautam and Manijeh Razeghi Quantum rep. 2020, 2(4), 591-599; https://doi.org/10.3390/quantum2040041 (registering DOI)-- December 4, 2020 ...[Visit Journal] This work demonstrates a mid-wavelength infrared InAs/InSb superlattice avalanche photodiode (APD). The superlattice APD structure was grown by molecular beam epitaxy on GaSb substrate. The device exhibits a 100 % cut-off wavelength of 4.6 µm at 150 K and 4.30 µm at 77 K. At 150 and 77 K, the device responsivity reaches peak values of 2.49 and 2.32 A/W at 3.75 µm under −1.0 V applied bias, respectively. The device reveals an electron dominated avalanching mechanism with a gain value of 6 at 150 K and 7.4 at 77 K which was observed under −6.5 V bias voltage. The gain value was measured at different temperatures and different diode sizes. The electron and hole impact ionization coefficients were calculated and compared to give a better prospect of the performance of the device. [reprint (PDF)]
4.	High power continuous wave operation of single mode quantum cascade lasers up to 5 W spanning λ∼3.8-8.3 µm Quanyong Lu, Steven Slivken, Donghai Wu, and Manijeh Razeghi Optics Express Vol. 28, Issue 10, pp. 15181-15188-- May 4, 2020 ...[Visit Journal] In this work, we report high power continuous wave room-temperature operation single mode quantum cascade lasers in the mid-infrared spectral range from 3.8 to 8.3 µm. Single mode robustness and dynamic range are enhanced by optimizing the distributed feedback grating coupling design and the facet coatings. High power single mode operation is secured by circumventing the over-coupling issue and spatial hole burning effect. Maximum single-facet continuous-wave output power of 5.1 W and wall plug efficiency of 16.6% is achieved at room temperature. Single mode operation with a side mode suppression ratio of 30 dB and single-lobed far field with negligible beam steering is observed. The significantly increased power for single mode emission will boost the QCL applications in long-range free-space communication and remote sensing of hazardous chemicals. [reprint (PDF)]
3.	High-performance short-wavelength infrared photodetectors based on type-II InAs/InAs_1-xSb_x/AlAs_1-xSb_x superlattices M. Razeghi, A. Haddadi, X. V. Suo, S. Adhikary, P. Dianat, R. Chevallier, A. M. Hoang, A. Dehzangi Proc. SPIE 9819, Infrared Technology and Applications XLII, 98190A -- May 20, 2016 ...[Visit Journal] We present a high-performance short-wavelength infrared n-i-p photodiode, whose structure is based on type-II superlattices with InAs/InAs_1-xSb_x/AlAs_1-xSb_x on GaSb substrate. At room temperature (300K) with front-side illumination, the device shows the peak responsivity of 0.47 A/W at 1.6mm, corresponding to 37% quantum efficiency at zero bias. At 300K, the device has a 50% cut-off wavelength of ~1.8mm. For −50mV applied bias at 300 K the photodetector has dark current density of 9.6x10^-5 A/cm² and RxA of 285 Ω•cm², and it revealed a detectivity of 6.45x10¹⁰ cm•Hz^½/W. Dark current density reached to 1.3x10^-8 A/cm² at 200 K, with 36% quantum efficiency which leads to the detectivity value of 5.66x10¹² cm•Hz^½/W. [reprint (PDF)]
3.	Background limited performance of long wavelength infrared focal plane arrays fabricated from type-II InAs/GaSb M-structure superlattice P.Y. Delaunay, B.M. Nguyen and M. Razeghi SPIE Porceedings, Vol. 7298, Orlando, FL 2009, p. 72981Q-- April 13, 2009 ...[Visit Journal] Recent advances in growth techniques, structure design and processing have lifted the performance of Type-II InAs/GaSb superlattice photodetectors. The introduction of a M-structure design improved both the dark current and R0A of Type-II photodiodes. This new structure combined with a thick absorbing region demonstrated background limited performance at 77K for a 300K background and a 2-π field of view. A focal plane array with a 9.6 μm 50% cutoff wavelength was fabricated with this design and characterized at 80K. The dark current of individual pixels was measured around 1.3 nA, 7 times lower than previous superlattice FPAs. This led to a higher dynamic range and longer integration times. The quantum efficiency of detectors without anti-reflective coating was 72%. The noise equivalent temperature difference reached 23 mK. The deposition of an anti-reflective coating improved the NEDT to 20 mK and the quantum efficiency to 89%. [reprint (PDF)]
3.	Generation-recombination and trap-assisted tunneling in long wavelength infrared minority electron unipolar photodetectors based on InAs/GaSb superlattice F. Callewaert, A.M. Hoang, and M. Razeghi Applied Physics Letters, 104, 053508 (2014)-- February 6, 2014 ...[Visit Journal] A long wavelength infrared minority electron unipolar photodetector based on InAs/GaSb type-II superlattices is demonstrated. At 77 K, a dark current of 3 × 10⁻⁵ A/cm² and a differential resistance-area of 3 700 Ω·cm² are achieved at the turn-on bias, with a 50%-cutoff of 10.0 μm and a specific detectivity of 6.2 × 10¹¹ Jones. The dark current is fitted as a function of bias and temperature using a model combining generation-recombination and trap-assisted tunneling. Good agreement was observed between the theory and the experimental dark current. [reprint (PDF)]
3.	High power, room temperature, Terahertz sources and frequency comb based on Difference frequency generation at CQD Manijeh Razeghi Proc. of SPIE 12230, 1223006, September 2022 ...[Visit Journal] Quantum cascade laser (QCL) is becoming the leading laser source in the mid-infrared and terahertz range due to its rapid development in power, efficiency, and spectral covering range. Owing to its unique intersubband transition and fast carrier lifetime, QCL possesses strong nonlinear susceptibilities that makes it the ideal platform for a variety of nonlinear optical generations. Among this, terahertz (THz) source based on difference-frequency generation (DFG)and frequency comb based on four wave mixing effect are the most exciting phenomena which could potentially revolutionize spectroscopy in mid-infrared (mid-IR) and THz spectral range. In this paper, we will briefly discuss the recent progress of our research. This includes high power high efficiency QCLs, high power room temperature THz sources based on DFG-QCL, room temperature THz frequency comb, and injection locking of high-power QCL frequency combs. The developed QCLs are great candidates as next generation mid-infrared source for spectroscopy and sensing. [reprint (PDF)]
3.	Antimonite-based gap-engineered type-II superlattice materials grown by MBE and MOCVD for the third generation of infrared imagers Manijeh Razeghi, Arash Dehzangi, Donghai Wu, Ryan McClintock, Yiyun Zhang, Quentin Durlin, Jiakai Li, Fanfei Meng Proc. SPIE Defense + Commercial Sensing,Infrared Technology and Applications XLV, 110020G -- May 7, 2019 ...[Visit Journal] Third generation of infrared imagers demand performances for higher detectivity, higher operating temperature, higher resolution, and multi-color detection all accomplished with better yield and lower manufacturing costs. Antimonidebased gap-engineered Type-II superlattices (T2SLs) material system is considered as a potential alternative for MercuryCadmium-Telluride (HgCdTe) technology in all different infrared detection regimes from short to very long wavelengths for the third generation of infrared imagers. This is due to the incredible growth in the understanding of its material properties and improvement of device processing which leads to design and fabrication of better devices. We will present the most recent research results on Antimonide-based gap-engineered Type-II superlattices, such as highperformance dual-band SWIR/MWIR photo-detectors and focal plane arrays for different infrared regimes, toward the third generation of infrared imaging systems at the Center for Zuantum Devices. Comparing metal-organic chemical vapor deposition (MOCVD), vs molecular beam epitaxy (MBE). [reprint (PDF)]
3.	Toward realization of small-size dual-band long-wavelength infrared photodetectors based on InAs/GaSb/AlSb type-II superlattices Romain Chevallier, Abbas Haddadi, Manijeh Razeghi Solid-State Electronics 136, pp. 51-54-- June 20, 2017 ...[Visit Journal] In this study, we demonstrate 12 × 12 µm² high-performance, dual-band, long-wavelength infrared (LWIR) photodetectors based on InAs/GaSb/AlSb type-II superlattices. The structure consists of two back-to-back heterojunction photodiodes with 2 µm-thick p-doped absorption regions. High quality dry etching combined with SiO₂ passivation results in a surface resistivity value of 7.9 × 10⁵ Ω·cm for the longer (red) channel and little degradation of the electrical performance. The device reaches dark current density values of 4.5 × 10⁻⁴ A/cm² for the longer (red) and 1.3 × 10⁻⁴ A/cm² for the shorter (blue) LWIR channels at quantum efficiency saturation. It has 50% cut-off wavelengths of 8.3 and 11.2 µm for the blue and red channel, respectively, at 77 K in back-side illumination configuration and exhibits quantum efficiencies of 37% and 29%, respectively. This results in specific detectivity values of 2.5 × 10¹¹ cm·Hz^½/W and 1.3 × 10¹¹ cm·Hz^½/W at 77 K. [reprint (PDF)]
3.	Type-II ‘M’ Structure Photodiodes: An Alternative Material Design for Mid-Wave to Long Wavelength Infrared Regimes B-M. Nguyen, M. Razeghi, V. Nathan, and G.J. Brown SPIE Conference, January 25-29, 2007, San Jose, CA Proceedings – Quantum Sensing and Nanophotonic Devices IV, Vol. 6479, p. 64790S-1-10-- January 29, 2007 ...[Visit Journal] In this work, an AlSb-containing Type-II InAs/GaSb superlattice, the so-called M-structure, is presented as a candidate for mid and long wavelength infrared detection devices. The effect of inserting an AlSb barrier in the GaSb layer is discussed and predicts many promising properties relevant to practical use. A good agreement between the theoretical calculation based on Empirical Tight Binding Method framework and experimental results is observed, showing the feasibility of the structure and its properties. A band gap engineering method without material stress constraint is proposed. [reprint (PDF)]
3.	Recent Advances in InAs/GaSb Superlattices for Very Long Wavelength Infrared Detection G.J. Brown, F. Szmulowicz, K. Mahalingam, S. Houston, Y. Wei, A. Gin and M. Razeghi SPIE Conference, San Jose, CA, Vol. 4999, pp. 457-- January 27, 2003 ...[Visit Journal] New infrared (IR) detector materials with high sensitivity, multi-spectral capability, improved uniformity and lower manufacturing costs are required for numerous long and very long wavelength infrared imaging applications. One materials system has shown great theoretical and, more recently, experimental promise for these applications: InAs/In_xGa_1-xSb type-II superlattices. In the past few years, excellent results have been obtained on photoconductive and photodiode samples designed for infrared detection beyond 15 microns. The infrared properties of various compositions and designs of these type-II superlattices have been studied. The infrared photoresponse spectra are combined with quantum mechanical modeling of predicted absorption spectra to provide insight into the underlying physics behind the quantum sensing in these materials. Results for superlattice photodiodes with cut-off wavelengths as long as 25 microns are presented. [reprint (PDF)]
3.	High Frequency Extended Short-Wavelength Infrared Heterojunction Photodetectors Based on InAs/GaSb/AlSb Type-II Superlattices Romain Chevallier, Abbas Haddadi, Ryan McClintock, Arash Dehzangi , Victor Lopez-Dominguez, Pedram Khalili Amiri, Manijeh Razeghi IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 54, NO. 6-- December 1, 2018 ...[Visit Journal] InAs/GaSb/AlSb type-II superlattice-based photodetectors, with 50% cut-off wavelength of 2.1 µm and a −3 dB cut-off frequency of 4.8 GHz, are demonstrated, for 10 µm diameter circular mesas under 15 V applied reverse bias. A study of the cut-off frequency with applied bias and mesa size was performed to evaluate some of the limiting factors of photodetectors high frequency performance. [reprint (PDF)]
3.	Recent advances in IR semiconductor laser diodes and future trends M. Razeghi; Y. Bai; N. Bandyopadhyay; B. Gokden; Q.Y. Lu; S. Slivken Photonics Society Summer Topical Meeting Series, IEEE [6000041], pp. 55-56 (2011)-- July 18, 2011 ...[Visit Journal] The wall plug efficiency of the mid-infrared quantum cascade laser in room temperature continuous wave (cw) operation is brought to 21%, with a maximum output power of 5.1 W. Using a surface grating distributed feedback (DFB) approach, we demonstrated 2.4 W single mode output in room temperature cw operation. With a photonic crystal distributed feedback (PCDFB) design, we achieved single mode spectrum and close to diffraction limited far field with a room temperature high peak power of 34 W. [reprint (PDF)]
3.	Background limited performance of long wavelength infrared focal plane arrays fabricated from M-structure InAs/GaSb superlattices P.Y. Delaunay, B.M. Nguyen, D. Hoffman, E.K. Huang, P. Manurkar, S. Bogdanov and M. Razeghi SPIE Proceedings, San Jose, CA Volume 7222-0W-- January 26, 2009 ...[Visit Journal] Recent advances in the design and fabrication of Type-II InAs/GaSb superlattices allowed the realization of high performance long wavelength infrared focal plane arrays. The introduction of an Mstructure barrier between the n-type contact and the pi active region reduced the tunneling component of the dark current. The M-structure design improved the noise performance and the dynamic range of FPAs at low temperatures. At 81K, the NEDT of the focal plane array was 23 mK. The noise of the camera was dominated by the noise component due to the read out integrated circuit. At 8 µm, the median quantum efficiency of the detectors was 71%, mainly limited by the reflections on the backside of the array. [reprint (PDF)]
3.	Modeling of Type-II InAs/GaSb Superlattices Using Empirical Tight-Binding Method and Interface Engineering Y. Wei and M. Razeghi Physical Review B, 69 (8)-- February 15, 2004 ...[Visit Journal] We report the most recent work on the modeling of type-II InAs/GaSb superlattices using the empirical tight binding method in an sp3s* basis. After taking into account the antimony segregation in the InAs layers, the modeling accuracy of the band gap has been improved. Our calculations agree with our experimental results within a certain growth uncertainty. In addition, we introduce the concept of Ga_xIn_1-x type interface engineering in order to reduce the lattice mismatch between the superlattice and the GaSb (001) substrate to improve the overall superlattice material quality. [reprint (PDF)]
3.	High performance LWIR Type-II InAs/GaSb superlattice photodetectors and infrared focal plane array Y. Wei, A. Hood, A. Gin, V. Yazdanpanah, M. Razeghi and M. Tidrow SPIE Conference, Jose, CA, Vol. 5732, pp. 309-- January 22, 2005 ...[Visit Journal] We report on the demonstration of a focal plane array based on Type-II InAs-GaSb superlattices grown on n-type GaSb substrate with a 50% cutoff wavelength at 10 μm. The surface leakage occurring after flip-chip bonding and underfill in the Type-II devices was suppressed using a double heterostructure design. The R₀A of diodes passivated with SiO₂ was 23 Ω·cm² after underfill. A focal plane array hybridized to an Indigo readout integrated circuit demonstrated a noise equivalent temperature difference of 33 mK at 81 K, with an integration time of 0.23 ms. [reprint (PDF)]
3.	2.4 W room temperature continuous wave operation of distributed feedback quantum cascade lasers Q.Y. Lu, Y. Bai, N. Bandyopadhyay, S. Slivken and M. Razeghi Applied Physics Letters, Vol. 98, No. 18, p. 181106-1-- May 4, 2011 ...[Visit Journal] We demonstrate high power continuous-wave room-temperature operation surface-grating distributed feedback quantum cascade lasers at 4.8 μm. High power single mode operation benefits from a combination of high-reflection and antireflection coatings. Maximum single-facet continuous-wave output power of 2.4 W and peak wall plug efficiency of 10% from one facet is obtained at 298 K. Single mode operation with a side mode suppression ratio of 30 dB and single-lobed far field without beam steering is observed. [reprint (PDF)]
3.	High performance Type-II InAs/GaSb superlattices for mid, long, and very long wavelength infrared focal plane arrays M. Razeghi, Y. Wei, A. Gin, A. Hood, V. Yazdanpanah, M.Z. Tidrow, and V. Nathan SPIE Conference, Orlando, FL, Vol. 5783, pp. 86-- March 28, 2005 ...[Visit Journal] We present our most recent results and review our progress over the past few years regarding InAs/GaSb Type-II superlattices for photovoltaic detectors and focal plane arrays. Empirical tight binding methods have been proven to be very effective and accurate in designing superlattices for various cutoff wavelengths from 3.7 µm up to 32 µm. Excellent agreement between theoretical calculations and experimental results has been obtained. High quality material growths were performed using an Intevac modular Gen II molecular beam epitaxy system. The material quality was characterized using x-ray, atomic force microscopy, transmission electron microscope and photoluminescence, etc. Detector performance confirmed high material electrical quality. Details of the demonstration of 256×256 long wavelength infrared focal plane arrays are presented. [reprint (PDF)]
3.	Dark current reduction in microjunction-based double electron barrier type-II InAs/InAsSb superlattice long-wavelength infrared photodetectors Romain Chevallier, Abbas Haddadi, & Manijeh Razeghi Scientific Reports 7, Article number: 12617-- October 3, 2017 ...[Visit Journal] Microjunction InAs/InAsSb type-II superlattice-based long-wavelength infrared photodetectors with reduced dark current density were demonstrated. A double electron barrier design was employed to reduce both bulk and surface dark currents. The photodetectors exhibited low surface leakage after passivation with SiO2, allowing the use of very small size features without degradation of the dark current. Fabricating microjunction photodetectors (25 × 25 µm² diodes with 10 × 10 µm² microjunctions) in combination with the double electron barrier design results in a dark current density of 6.3 × 10⁻⁶ A/cm² at 77 K. The device has an 8 µm cut-off wavelength at 77 K and exhibits a quantum efficiency of 31% for a 2 µm-thick absorption region, which results in a specific detectivity value of 1.2 × 10¹² cm·Hz^½/W. [reprint (PDF)]
3.	Optimizing facet coating of quantum cascade lasers for low power consumption Y. Bai, S.R. Darvish, N. Bandyopadhyay, S. Slivken and M. Razeghi Journal of Applied Physics, Vol. 109, No. 5, p. 053103-1-- March 1, 2011 ...[Visit Journal] Typical high power consumption (∼10 W) of mid-infrared quantum cascade lasers (QCLs) has been a serious limitation for applications in battery powered systems. A partial high-reflection (PHR) coating technique is introduced for power downscaling with shorter cavity lengths. The PHR coating consists of a double layer dielectric of SiO₂ and Ge. With this technique, a 4.6 μm QCL with an ultra low threshold power consumption of less than a watt (0.83 W) is demonstrated in room temperature continuous wave operation. At 25°C, the maximum output power and wall plug efficiency are 192 mW and 8.6%, respectively. [reprint (PDF)]

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