Center for Quantum Devices - Most Downloaded Journal Articles

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1.	Room temperature operation of In_xGa_1-xSb/InAs type-II quantum well infrared photodetectors grown by MOCVD D. H. Wu, Y. Y. Zhang, and M. Razeghi Applied Physics Letters 112, 111103-- March 14, 2018 ...[Visit Journal] We demonstrate room temperature operation of In_0.5Ga_0.5Sb/InAs type-II quantum well photodetectors on InAs substrate grown by metal-organic chemical vapor deposition. At 300 K, the detector exhibits a dark current density of 0.12 A/cm², peak responsivity of 0.72 A/W corresponding to a quantum efficiency of 23.3%, with calculated specific detectivity of 2.4×10⁹ cm.Hz^1/2/W at 3.81 μm. [reprint (PDF)]
1.	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)]
1.	High power 1D and 2D photonic crystal distributed feedback quantum cascade lasers B. Gokden, Y. Bai, S. Tsao, N. Bandyopadhyay, S. Slivken and M. Razeghi SPIE Proceedings, San Francisco, CA (January 22-27, 2011), Vol. 7945, p. 79450C-- January 23, 2011 ...[Visit Journal] For many practical applications that need bright sources of mid-infrared radiation, single mode operation and good beam quality are also required. Quantum cascade lasers are prominent candidates as compact sources of mid-infrared radiation capable of delivering very high power both CW and under pulsed operation. While 1D photonic crystal distributed feedback structures can be used to get single mode operation from quantum cascade lasers with narrow ridge widths, novel 2D photonic crystal cavity designs can be used to improve spectral and spatial purity of broad area quantum cascade lasers. In this paper, we demonstrate high power, spatially and spectrally pure operation at room temperature from narrow ridge and broad area quantum cascade lasers with buried 1D and 2D photonic crystal structures. Single mode continuous wave emission at λ = 4.8 μm up to 700 mW in epi-up configuration at room temperature was observed from a 11 μm wide 5 mm long distributed feedback quantum cascade laser with buried 1D gratings. High peak powers up to 34 W was obtained from a 3mm long 400 μm wide 2D photonic crystal distributed feedback laser at room temperature under pulsed operation. The far field profile had a single peak normal to the laser facet and the M2 figure of merit was as low as 2.5. Emission spectrum had a dominating single mode at λ = 4.36 μm. [reprint (PDF)]
1.	High power photonic crystal distributed feedback quantum cascade lasers emitting at 4.5 micron B. Gokden, S. Slivken and M. Razeghi SPIE Proceedings, San Francisco, CA (January 22-28, 2010), Vol. 7608, p. 760806-1-- January 22, 2010 ...[Visit Journal] Quantum cascade lasers possess very small linewidth enhancement factor, which makes them very prominent candidates for realization of high power, nearly diffraction limited and single mode photonic crystal distributed feedback broad area lasers in the mid-infrared frequencies. In this paper, we present room temperature operation of a two dimensional photonic crystal distributed feedback quantum cascade laser emitting at 4.5 µm. peak power up to ~0.9 W per facet is obtained from a 2 mm long laser with 100 µm cavity width at room temperature. The observed spectrum is single mode with a very narrow linewidth. Far-field profile has nearly diffraction limited single lobe with full width at half maximum of 3.5 degree normal to the facet. The mode selection and power output relationships are experimentally established with respect to different cavity lengths for photonic crystal distributed feedback quantum cascade lasers. [reprint (PDF)]
1.	Fabrication of nanostructured heterojunction LEDs using self-forming Moth-Eye Arrays of n-ZnO Nanocones Grown on p-Si (111) by PLD D.J. Rogers; V.E. Sandana; F. Hosseini Teherani; M. Razeghi; H.-J. Drouhin Proc. SPIE 7217, Zinc Oxide Materials and Devices IV, 721708 (February 17, 2009)-- February 17, 2009 ...[Visit Journal] ZnO nanostructures were grown on Si (111) substrates using Pulsed Laser Deposition. The impact of growth temperature (T_s) and Ar pressure (P_Ar) on the morphology, crystal structure and photoluminescence was investigated. Various types of ZnO nanostructures were obtained. Self-forming arrays of vertically-aligned nanorods and nanocones with strong c-axis crystallographic orientation and good optical response were obtained at higher T_s. The nanocone, or "moth-eye" type structures were selected for LED development because of their graded effective refractive index, which could facilitate improved light extraction at the LED/air interface. Such moth-eye arrays were grown on p-type Si (111) substrates to form heteroj unction LEDs with the n-type ZnO nanocones acting as an active component of the device. These nanostructured LEDs gave rectifying I/V characteristics with a threshold voltage of about 6V and a blueish-white electroluminescence, which was clearly visible to the naked eye. [reprint (PDF)]
1.	Room temperature continuous wave operation of quantum cascade lasers with 12.5% wall plug efficiency Y. Bai, S. Slivken, S.R. Darvish, and M. Razeghi Applied Physics Letters, Vol. 93, No. 2, p. 021103-1-- July 14, 2008 ...[Visit Journal] An InP based quantum cascade laser heterostructure emitting at 4.6 µm was grown with gas-source molecular beam epitaxy. The wafer was processed into a conventional double-channel ridge waveguide geometry with ridge widths of 19.7 and 10.6 µm without semi-insulating InP regrowth. An uncoated, narrow ridge device with a 4.8 mm cavity length was epilayer down bonded to a diamond submount and exhibits 2.5 W maximum output power with a wall plug efficiency of 12.5% at room temperature in continuous wave operation. [reprint (PDF)]
1.	ZnO 3D flower-like nanostructure synthesized on GaN epitaxial layer by simple route hydrothermal process J.M. Jung, C.R. Kim, H. Ryu, M. Razeghi and W.G. Jung Journal of Alloys and Compounds-- September 15, 2007 ...[Visit Journal] The 3D type, flower-like ZnO nanostructures from particle to flower-like or chestnut bur are fabricated on the GaN epitaxial layer substrate through the simple-route hydrothermal process. Structural characterization was made for the ZnO 3D nanostructures synthesized in different pH ranging from 9.5 to 11.0. The growth model was proposed and discussed regarding the fabrication mechanism and morphology of ZnO 3D flower-like nanostructure. The flower-like ZnO is composed of many thin single crystals ZnO nanorods. Bigger and thicker ZnO structure is fabricated with the increase of pH in solution. The enhanced UV emission in the PL measurement and the spectra in the Raman spectroscopy for ZnO–GaN heterojunction material were discussed. [reprint (PDF)]
1.	Type-II InAs/GaSb Superlattice Focal Plane Arrays for High-Performance Third Generation Infrared Imaging and Free-Space Communication M. Razeghi, A. Hood and A. Evans SPIE Conference, January 25-29, 2007, San Jose, CA Proceedings – Optoelectronic Integrated Circuits IX, Vol. 6476, p. 64760Q-1-9-- January 29, 2007 ...[Visit Journal] Free-space optical communications has recently been touted as a solution to the "last mile" bottleneck of high speed data networks providing highly secure, short to long range, and high bandwidth connections. However, commercial near infrared systems experience atmospheric scattering losses and scintillation effects which can adversely affect a link's uptime. By moving the operating wavelength into the mid or long wavelength infrared enhanced link uptimes and increased range can be achieved due to less susceptibility atmospheric affects. The combination of room temperature, continuous wave' high power quantum cascade lasers and high operating temperature Type-II superlattice photodetectors offers the benefits of mid and long wavelength infrared systems as well as practical operating conditions. [reprint (PDF)]
1.	Fabrication of GaN nanotubular material using MOCVD with aluminum oxide membrane W.G. Jung, S.H. Jung, P. Kung, and M. Razeghi SPIE Conference, San Jose, CA, Vol. 6127, pp. 61270K-- January 23, 2006 ...[Visit Journal] GaN nanotubular material is fabricated with aluminum oxide membrane in MOCVD. SEM, XRD, TEM and PL are employed to characterize the fabricated GaN nanotubular material. An aluminum oxide membrane with ordered nano holes is used as template. Gallium nitride is deposited at the inner wall of the nano holes in aluminum oxide template, and the nanotubular material with high aspect ratio is synthesized using the precursors of TMG and ammonia gas. Optimal synthesis condition in MOCVD is obtained successfully for the gallium nitride nanotubular material in this research. The diameter of GaN nanotube fabricated is approximately 200 ~ 250 nm and the wall thickness is about 40 ~ 50 nm. GaN nanotubular material consists of numerous fine GaN particulates with sizes ranging 15 to 30 nm. [reprint (PDF)]
1.	A detailed analysis of carrier transport in InAs0.3Sb0.7 layers grown on GaAs substrates by metalorganic chemical vapor deposition C. Besikci, Y.H. Choi, G. Labeyrie, E. Bigan and M. Razeghi with J.B. Cohen, J. Carsello, and V.P. Dravid Journal of Applied Physics 76 (10)-- November 15, 1994 ...[Visit Journal] InAs_0.3Sb_0.7 layers with mirrorlike morphology have been grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition. A room‐temperature electron Hall mobility of 2×10⁴ cm²/V· s has been obtained for a 2 μm thick layer. Low‐temperature resistivity of the layers depended on TMIn flow rate and layer thickness. Hall mobility decreased monotonically with decreasing temperature below 300 K. A 77 K conductivity profile has shown an anomalous increase in the sample conductivity with decreasing thickness except in the near vicinity of the heterointerface. In order to interpret the experimental data, the effects of different scattering mechanisms on carrier mobility have been calculated, and the influences of the lattice mismatch and surface conduction on the Hall measurements have been investigated by applying a three‐layer Hall‐effect model. Experimental and theoretical results suggest that the combined effects of the dislocations generated by the large lattice mismatch and strong surface inversion may lead to deceptive Hall measurements by reflecting typical n‐type behavior for a p‐type sample, and the measured carrier concentration may considerably be affected by the surface conduction up to near room temperature. A quantitative analysis of dislocation scattering has shown significant degradation in electron mobility for dislocation densities above 10⁷ cm⁻². The effects of dislocation scattering on hole mobility have been found to be less severe. It has also been observed that there is a critical epilayer thickness (∼1 μm) below which the surface electron mobility is limited by dislocation scattering. [reprint (PDF)]
1.	Infrared Imaging Arrays Using Advanced III-V Materials and technology M. Razeghi, J.D. Kim, C. Jelen, S. Slivken, E. Michel, H. Mohseni, J.J. Lee, J. Wojkowski, K.S. Kim, H.I. Jeon, and J. X IEEE Proceedings, Advanced Workshop on Frontiers in Electronics (WOFE), Tenerife, Spain;-- January 6, 1997 ...[Visit Journal] Photodetectors operating in the 3-5 and 8-12 μm atmospheric windows are of great importance for applications in infrared (IR) thermal imaging. HgCdTe has been the dominant material system for these applications. However, it suffers from instability and non-uniformity problems over large areas due to high Hg vapor pressure during the material, growth. There has been a lot of interest in the use of heteroepitaxially grown Sb-based alloys, its strained layer superlattices, and GaAs based quantum wells as alternatives to MCT. This interest has been driven by the advanced material growth and processing technology available for the III-V material system [reprint (PDF)]
1.	High-Power Continuous-Wave Operation of a 6 µm Quantum-Cascade Laser at Room Temperature J.S. Yu, S. Slivken, A. Evans, L. Doris, and M. Razeghi Applied Physics Letters, 83 (13)-- September 29, 2003 ...[Visit Journal] We report continuous-wave (cw) operation of quantum-cascade lasers (λ= 6 µm) using a thick electroplated Au top contact layer and epilayer-up bonding on a copper heat sink up to a temperature of 308 K (35 °C). The high cw optical output powers of 132 mW at 293 K and 21 mW at 308 K are achieved with threshold current densities of 2.29 and 2.91 kA/cm², respectively, for a high-reflectivity-coated 15 µm wide and 2 mm long laser. [reprint (PDF)]
1.	High power InAsSb/InPAsSb/InAs mid-infrared lasers A. Rybaltowski, Y. Xiao, D. Wu, B. Lane, H. Yi, H. Feng, J. Diaz, and M. Razeghi Applied Physics Letters 71 (17)-- October 27, 1997 ...[Visit Journal] We demonstrate high-power InAsSb/InPAsSb laser bars (λ ≈ 3.2 μm) consisting of three 100 μm-wide laser stripes of 700 μm cavity length, with peak output power up to 3 W at 90 K, and far-fields for the direction perpendicular to the junction as narrow as 12° full width half maximum. Spectra and far-field patterns of the laser bars are shown to have excellent characteristics for a wide range of operating conditions, suggesting the possibility of even higher light power emission with good beam quality. Joule heating is shown to be the major factor limiting higher power operation. [reprint (PDF)]
1.	Type-II InAs/GaSb/AlSb superlatticebased heterojunction phototransistors: back to the future Abbas Haddadi, Arash Dehzangi, Romain Chevallier, Thomas Yang, Manijeh Razeghi Proc. SPIE 10540, Quantum Sensing and Nano Electronics and Photonics XV- Page-1054004-1-- January 26, 2018 ...[Visit Journal] Most of reported HPTs in literatures are based on InGaAs compounds that cover NIR spectral region. However, InGaAs compounds provide limited cut-off wavelength tunability. In contrast, type-II superlattices (T2SLs) are a developing new material system with intrinsic advantages such as great flexibility in bandgap engineering, low growth and manufacturing cost, high-uniformity, auger recombination suppression, and high carrier effective mass that are becoming an attractive candidate for infrared detection and imaging from short-wavelength infrared to very long wavelength infrared regime. We present the recent advancements in T2SL-based heterojunction phototransistors in e– SWIR, MWIR and LWIR spectral ranges. A mid-wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb superlattices on GaSb substrate has been demonstrated. Then, we present the effect of vertical scaling on the optical and electrical performance of heterojunction phototransistors, where the performance of devices with different base width was compared as the base was scaled from 60 down to 40 nm. [reprint (PDF)]
1.	Effect of sidewall surface recombination on the quantum efficiency in a Y₂O₃ passivated gated type-II InAs/GaSb long-infrared photodetector array G. Chen, A. M. Hoang, S. Bogdanov, A. Haddadi, S. R. Darvish, and M. Razeghi Appl. Phys. Lett. 103, 223501 (2013)-- November 25, 2013 ...[Visit Journal] Y₂O₃ was applied to passivate a long-wavelength infrared type-II superlattice gated photodetector array with 50% cut-off wavelength at 11 μm, resulting in a saturated gate bias that was 3 times lower than in a SiO₂ passivated array. Besides effectively suppressing surface leakage, gating technique exhibited its ability to enhance the quantum efficiency of 100 × 100 μm size mesa from 51% to 57% by suppressing sidewall surface recombination. At 77 K, the gated photodetector showed dark current density and resistance-area product at −300 mV of 2.5 × 10⁻⁵ A/cm² and 1.3 × 10⁴ Ω·cm², respectively, and a specific detectivity of 1.4 × 10¹² Jones. [reprint (PDF)]
1.	Advances in UV sensitive visible blind GaN-based APDs M. Ulmer, R. McClintock and M. Razeghi SPIE Proceedings, San Francisco, CA (January 22-27, 2011), Vol. 7945, p. 79451G-- January 23, 2011 ...[Visit Journal] In this paper, we describe our current state-of-the-art process of making visible-blind APDs based on GaN. We have grown our material on both conventional sapphire and low dislocation density free-standing c- and m-plane GaN substrates. Leakage current, gain, and single photon detection efficiency (SPDE) of these APDs are compared. The spectral response and Geiger-mode photon counting performance of UV APDs are studied under low photon fluxes. Single photon detection capabilities with over 30% are demonstrated. We show how with pulse height discrimination the Geiger-mode operation conditions can be optimized for enhanced SPDE versus dark counts. [reprint (PDF)]
1.	Very high wall plug efficiency of quantum cascade lasers Y. Bai, S. Slivken, S.R. Darvish, and M. Razeghi SPIE Proceedings, San Francisco, CA (January 22-28, 2010), Vol. 7608, p. 76080F-1-- January 22, 2010 ...[Visit Journal] We demonstrate very high wall plug efficiency (WPE) of mid-infrared quantum cascade lasers (QCLs) in low temperature pulsed mode operation (53%), room temperature pulsed mode operation (23%), and room temperature continuous wave operation (18%). All of these values are the highest to date for any QCLs. The optimization of WPE takes the route of understanding the limiting factors of each sub-efficiency, exploring new designs to overcome the limiting factor, and constantly improving the material quality. [reprint (PDF)]
1.	Thermal analysis of buried heterostructure quantum cascade lasers for long-wavelength infrared emission using 2D anisotropic heat-dissipation model H.K. Lee, K.S. Chung, J.S. Yu and M. Razeghi Physica Status Solidi (a), Vol. 206, p. 356-362-- February 1, 2009 ...[Visit Journal] We have theoretically investigated and compared the thermal characteristics of 10.6 μm InGaAs/InAlAs/InP buried heterostructure (BH) quantum cascade lasers (QCLs) with different heat-sinking configurations by a steady-state heat-transfer analysis. The heat-source densities were obtained from laser threshold power densities measured experimentally under room-temperature continuous-wave mode. The two-dimensional anisotropic heat-dissipation model was used to calculate the temperature distribution, heat flux, and thermal conductance (Gth) inside the device. For good thermal characteristics, the QCLs in the long-wavelength infrared region require the relatively narrow BH structure in combination with epilayer-down bonding due to thick active core/cladding layers and high insulator losses. The single-ridge BH structure results in slightly higher thermal conductance by 2-4% than the double-channel (DC) ridge BH structure. For W = 12 m with 5 μm thick electroplated Au, the single-ridge BH laser with epilayer-down bonding exhibited the highest G_th value of 201.9 W/K cm², i.e. increased by nearly 36% with respect to the epilayer-up bonded DC ridge waveguide laser. This value is improved by 50% and 62% with respect to the single-ridge BH laser and DC ridge waveguide laser with W = 20 μm in the epilayer-up bonding scheme, respectively. [reprint (PDF)]
1.	Investigations of ZnO thin films grown on c-Al(2)O(3) by pulsed laser deposition in N(2) + O(2) ambient D.J. Rogers, D.C. Look, F.H. Teherani, K. Minder, M. Razeghi, A. Largeteau, G. Demazeau, J. Morrod, K.A. Prior, A. Lusson, and S. Hassani Physica Status Solidi (c), Vol. 5, No. 9, p. 3084-3087-- July 1, 2008 ...[Visit Journal] ZnO films were deposited on c-Al₂O₃ using pulsed laser deposition both with and without N₂ in the growth ambient. X-ray diffraction revealed poorer crystal quality and surface morphology for one-step growths with N₂ in the ambient. A marked improvement in both the crystallographic and surface quality was obtained through use of two-step growths employing nominally undoped ZnO buffer layers prior to growth with N₂ in the ambient. All films showed majority n-type conduction in Hall measurements. Post-annealing for 30 minutes at 600 ºC in O₂ systematically reduced both the carrier concentration and the conductivity. A base room temperature carrier concentration of ~ 10¹⁶ cm^-3 was linked to Al diffusing from the substrate. 4.2 K photoluminescence spectra exhibited blue bands associated with the growths having N₂ in the ambient. Temperature dependent Hall measurements were consistent with N being incorporated in the films. Processed devices did not, however, show rectifying behavior or electroluminescence. [reprint (PDF)]
1.	Scaling in back-illuminated GaN avalanche photodiodes K. Minder, J.L. Pau, R. McClintock, P. Kung, C. Bayram, M. Razeghi and D. Silversmith Applied Physics Letters, Vol. 91, No. 7, p. 073513-1-- August 13, 2007 ...[Visit Journal] Avalanche p-i-n photodiodes of various mesa areas were fabricated on AlN templates for back illumination for enhanced performance through hole-initiated multiplication, and the effects of increased area on device performance were studied. Avalanche multiplication was observed in mesa sizes up to 14,063 µm^2 under linear mode operation. Uniform gain and a linear increase of the dark current with area were demonstrated. [reprint (PDF)]
1.	Techniques for High-Quality SiO₂ Films J. Nguyen and M. Razeghi SPIE Conference, January 25-29, 2007, San Jose, CA Proceedings – Quantum Sensing and Nanophotonic Devices IV, Vol. 6479, p. 64791K-1-8-- January 29, 2007 ...[Visit Journal] We report on the comparison of optical, structural, and electrical properties of SiO₂ using plasma-enhanced chemical vapor deposition and ion-beam sputtering deposition. High-quality, low-temperature deposition of SiO₂ by ion-beam sputtering deposition is shown to have lower absorption, smoother and more densely packed films, a lower amount of fixed oxide charges, and a lower trapped-interface density than SiO₂ by plasma-enhanced chemical vapor deposition. This high-quality SiO₂ is then demonstrated as an excellent electrical and mechanical surface passivation layer on Type-II InAs/GaSb photodetectors [reprint (PDF)]
1.	Avalanche multiplication in AlGaN based solar-blind photodetectors R. McClintock, A. Yasan, K. Minder, P. Kung, and M. Razeghi Applied Physics Letters, 87 (24)-- December 12, 2005 ...[Visit Journal] Avalanche multiplication has been observed in solar-blind AlGaN-based p-i-n photodiodes. Upon ultraviolet illumination, the optical gain shows a soft breakdown starting at relatively low electric fields, eventually saturating without showing a Geiger mode breakdown. The devices achieve a maximum optical gain of 700 at a reverse bias of 60 V. By modeling the device, it is found that this corresponds to an electric-field strength of 1.7 MV/cm. [reprint (PDF)]
1.	Optoelectronic Integrated Circuits (OEICs) for Next Generation WDM Communications M. Razeghi and S. Slivken SPIE Conference, Boston, MA, -- July 29, 2002 ...[Visit Journal] This paper reviews some of the key enabling technologies for present and future optoelectronic intergrated circuits. This review concentrates mainly on technology for lasers, waveguides, modulators, and fast photodetectors as the basis for next generation communicatiosn systems. Emphasis is placed on intergrations of components and mass production of a generic intelligent tranciever. [reprint (PDF)]
1.	Photoluminescence Study of AlGaN-based 280 nm Ultraviolet Light-Emitting Diodes A. Yasan, R. McClintock, K. Mayes, D.H. Kim, P. Kung, and M. Razeghi Applied Physics Letters, 83 (20)-- November 17, 2003 ...[Visit Journal] We investigated optical properties of single quantum well AlGaN-based UV 280 nm light-emitting diodes using temperature-dependent photoluminescence (PL) measurement. We found an "S-shaped" temperature dependence of the peak energy. From the Arrhenius plot of integrated PL intensity, we speculate that dislocations as well as thermal emission of carriers out of the quantum well are responsible for the PL quenching behavior. Also a second nonradiative channel with much lower activation energy was found, the origin of which we believe to be quenching of the bound excitons [reprint (PDF)]
1.	Broadband monolithically-tunable quantum cascade lasers Wenjia Zhou, Ryan McClintock, Donghai Wu, Steven Slivken, Manijeh Razeghi Proc. SPIE 10540, Quantum Sensing and Nano Electronics and Photonics XV, 105400A-- January 26, 2018 ...[Visit Journal] Mid-infrared lasers, emitting in the spectral region of 3-12 μm that contain strong characteristic vibrational transitions of many important molecules, are highly desirable for spectroscopy sensing applications. High efficiency quantum cascade lasers have been demonstrated with up to watt-level output power in the mid-infrared region. However, the wide wavelength tuning, which is critical for spectroscopy applications, is still largely relying on incorporating external gratings, which have stability issues. Here, we demonstrate the development a monolithic, widely tunable quantum cascade laser source emitting between 6.1 and 9.2 μm through an on-chip integration of a sampled grating distributed feedback tunable laser array with a beam combiner. A compact tunable laser system was built to drive the individual lasers within the array and coordinate the driving of the laser array to produce desired wavelength. A broadband spectral measurement (520cm^-1) of methane shows excellent agreement with Fourier transform infrared spectrometer measurement. Further optimizations have led to high performance monolithic tunable QCLs with up to 65 mW output while delivering fundamental mode outputs. [reprint (PDF)]

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