Thermal imaging of buried heterostructure quantum cascade lasers (QCLs) and QCL arrays using CCD-based thermoreflectance microscopy

Becher, N.; Farzaneh, M.; Knipfer, B.; Sigler, C.; Kirch, Jeremy; Boyle, C.; Botez, D.; Mawst, Luke J.; Lindberg, D.; Earles, T.

doi:10.1063/1.5065507

Cited by 12 publications

(7 citation statements)

References 36 publications

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“…Several laser cores are placed equal-distance apart for efficient heat extraction. [30][31][32] However, because of thermal cross-talk, suboptimal beam quality in QCL arrays at high output power can prevent their CW operation. [31] We thus analyze the thermal behavior of QCL arrays and compare their performance with an isolated QCL.…”

Section: Resultsmentioning

confidence: 99%

Near‐Field Thermal Profiling and 3D Anisotropic Thermal Analysis of Quantum Cascade Lasers

Abbas

Daunis²,

Pandey³

et al. 2022

Physica Status Solidi (a)

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Quantum cascade lasers (QCLs) are unipolar light sources wherein intersubband transitions of electrons occur in repeated layers of superlattices composed of semiconductor gain media. [1] The emission wavelength of QCLs is determined by the superlattice layer thickness and the material composition. Therefore, it can be tuned over a wide range in a given material system. [2] The typical operation wavelength of QCLs is in the mid-infrared (3.5-24 μm) and terahertz (1.2-4.9 THz). [3,4] Because the vibrational modes of many chemical compounds lie in the wavelength range of 3 to 15 μm, mid-infrared QCLs have found various applications in biological and chemical warfare agent detection [5,6] and pollutant detection, [7] and noninvasive medical diagnostics. [5] They can also be used in optical wireless communication: [8] the "terahertz gap" appears due to the absence of radiation sources in this frequency range, and THz QCLs fill the terahertz gap and have been used in imaging and spectroscopy. [9][10][11] However, the low thermal conductivity of QCL's multilayer superlattice gain medium and the ample operational electrical power cause significant self-heating in QCLs, [12,13] which, over time, results in a rise in lasing threshold current, [6] a decrease in output power, [14] and even device failure. [15] Therefore, to better understand QCL's failure mechanism, thermal analysis and monitoring are necessary for designing QCLs with optimal performance.Techniques for temperature monitoring include microphotoluminescence, [16] Raman spectroscopy, [17] thermoreflectance spectroscopy, [18] lock-in IR Thermography, [19] and infrared scanning near field optical microscopy (IR-SNOM). [20] For example, Raman spectroscopy as a non-contact thermometer was used to study output facet heating in an uncoated high-power continuous-wave QCL emitting at 8.5 μm. [17] A comparison of the spatial and temperature resolutions of these techniques can be found in Ref. [21] In this work, we report on developing an IR-SNOM technique with high temperature and spatial resolutions, both achieved by opening a subwavelength aperture at the tip of an IR fiber optic probe. We apply this technique to study the time constants in InP/InAlAs/InGaAs buried heterostructure (BH) mounted epi-layer side down QCLs--a geometry reported to have the best thermal performance by Pieŕscínska et al. [22] To verify the experimental findings, we develop an anisotropic 3D model to study steady-state and

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Section: Resultsmentioning

confidence: 99%

Near‐Field Thermal Profiling and 3D Anisotropic Thermal Analysis of Quantum Cascade Lasers

Abbas

Daunis²,

Pandey³

et al. 2022

Physica Status Solidi (a)

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“…[1]- [3] High resolution experimental investigation of thermal effects in semiconductor lasers have been done with a number of techniques including IR-SNOM [4], [5]and CCD thermoreflectance imaging (CCD-TR). CCD-TR is a wellestablished technique to measure the surface temperature of electronic and optoelectronic devices and has been used for the thermal characterization of high power lasers [6], VCSELs [6]- [9], quantum dot lasers and quantum cascade lasers (QCLs) [10]- [12]. In this work we use CCD-TR imaging to image the surface temperature of a single frequency single-mode slotted semiconductor laser operating at approximately 1550 nm.…”

Section: Introductionmentioning

confidence: 99%

Thermoreflectance Imaging of Semiconductor Lasers With a Numerical Thermal Model

McKenna

Corbett

Naimi

et al. 2022

IEEE J. Select. Topics Quantum Electron.

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High resolution surface temperature maps of a slotted surface grating laser operating at approx. 1550 nm are obtained by means of CCD-thermoreflectance imaging. The resolution is such that the temperature of the 2 µm wide ridge can be determined. Experimental temperature profiles along the ridge and in the lateral direction are provided. A 2D numerical model is developed to simulate the steady state thermal distributions in the laser. There is good agreement between the experiment and simulation. This technique allows for high-resolution imaging and will be useful where hot spots occur on laser devices.

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“…The heat dissipation plays a critical role in the device performance of mid-IR QCLs. Among the methods used to reduce the laser overheating are the optimization of the laser active region and waveguide design, the processing technology, mounting and device packaging [ 11 , 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

In-Depth Experimental Analysis of Influence of Electroplated Gold Thickness on Thermal and Electro-Optical Properties of mid-IR AlInAs/InGaAs/InP Quantum Cascade Lasers

Pierścińska¹,

Pierściński²,

Sobczak³

et al. 2021

Materials

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In this paper, we have examined the influence of electroplated gold thickness on the thermal and electro-optical properties of mid-IR AlInAs/InGaAs, InP QCLs. The experimental results show a significant reduction of the temperature of QCL active region (AR) with increasing gold layer thickness. For QCLs with 5.0 μm gold thickness, we observed a 50% reduction of the active region temperature. An improvement of key electro-optical parameters, that is, threshold current density and maximum emitted power for structures with thick gold, was observed. The results of micro-Raman characterization show that the electroplated gold layer introduces only moderate compressive strain in top InP cladding, which is well below the critical value for the creation of misfit dislocations.

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Thermal imaging of buried heterostructure quantum cascade lasers (QCLs) and QCL arrays using CCD-based thermoreflectance microscopy

Cited by 12 publications

References 36 publications

Near‐Field Thermal Profiling and 3D Anisotropic Thermal Analysis of Quantum Cascade Lasers

Near‐Field Thermal Profiling and 3D Anisotropic Thermal Analysis of Quantum Cascade Lasers

Thermoreflectance Imaging of Semiconductor Lasers With a Numerical Thermal Model

In-Depth Experimental Analysis of Influence of Electroplated Gold Thickness on Thermal and Electro-Optical Properties of mid-IR AlInAs/InGaAs/InP Quantum Cascade Lasers

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