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Center emission wavelength vs temperature. The inset illustrates the spectra for T = 300 K (dashed) and 315 K (solid).
Source publication
Type-II “W” diode lasers with ten quantum-well periods operated in pulsed mode to 315 K, where the emission wavelength was 4.02 μm. The devices with uncoated facets had a threshold current density of 145 A∕cm2 and slope efficiency of 47 mW∕A per facet at 78 K, and displayed a characteristic temperature T0≈46 K in the range 78–300 K.
Contexts in source publication
Context 1
... powers and slope efficiencies are corrected for the collection efficiency of 67%, which was determined by comparing to cw measurements that employed a large-area thermopile detector to collect all of the emitted light. Figures 2 and 3 show temperature dependencies of the pulsed threshold current density and emission wavelength, respectively, as determined from measurements of the L -I and spectral characteristics. At T = 78 K, where = 3.56 m, the threshold of 145 A / cm 2 is only slightly higher (up to a factor of 2.3) than the j th for previous W diodes emitting at shorter wavelengths. ...Context 2
... structures contained only five QW periods, and most showed a more rapid increase of j th at higher temperatures. For fits covering the entire temperature range between 78 and 300 K, the present characteristic temperature of T 0 = 46 K exceeds all earlier results, and T max = 315 K = 4.02 m. The temperature shift of the emission wavelength in Fig. 3 is due primarily to the variation of the energy gap. The inset to Fig. 3 shows spectra for T = 300 and 315 K. The linewidths of 12 nm are comparable to the narrowest results for optically pumped W lasers operating in pulsed mode in this wavelength range. 14 The short-pulse nature of the present excitation may contribute to the ...Context 3
... increase of j th at higher temperatures. For fits covering the entire temperature range between 78 and 300 K, the present characteristic temperature of T 0 = 46 K exceeds all earlier results, and T max = 315 K = 4.02 m. The temperature shift of the emission wavelength in Fig. 3 is due primarily to the variation of the energy gap. The inset to Fig. 3 shows spectra for T = 300 and 315 K. The linewidths of 12 nm are comparable to the narrowest results for optically pumped W lasers operating in pulsed mode in this wavelength range. 14 The short-pulse nature of the present excitation may contribute to the linewidth. Figure 4 plots the temperature dependence of the external slope ...Similar publications
Single-mode and single-beam surface emission (675–680 nm) has been achieved from visible red GaInP/AlGaInP laser diodes by applying the surface mode emission technique. The laser diodes emit a single beam via the surface with a beam divergence of 0.16° and show single-mode emission both in ac as well as in dc operation with a minimum spectral linew...
Citations
... The first ICLs designed, grown, processed, and characterized at NRL were reported in 2006 [53]. At that time, "W" diode lasers with similar active QWs were operating in pulsed mode at RT [54], albeit with threshold current densities well in excess of 10 kA/cm 2 . The early NRL ICL designs employed "W" active regions, single-QW hole injectors, and relatively thick electron injectors with low doping in four of the wells. ...
... The typical top cladding thickness of 1.5 µm for NRL structures emitting at λ = 4 µm (and assuming thick SCLs) is designed to reduce the nominal loss to < 0.1 cm −1 . Additional loss also occurs if the bottom cladding is too thin, since the mode then leaks into the high-index GaSb substrate [54]. The maximum value of this spectrally-modulated loss is: ...
We review the history, development, design principles, experimental operating characteristics, and specialized architectures of interband cascade lasers for the mid-wave infrared spectral region. We discuss the present understanding of the mechanisms limiting the ICL performance and provide a perspective on the potential for future improvements. Such device properties as the threshold current and power densities, continuous-wave output power, and wall-plug efficiency are compared with those of the quantum cascade laser. Newer device classes such as ICL frequency combs, interband cascade vertical-cavity surface-emitting lasers, interband cascade LEDs, interband cascade detectors, and integrated ICLs are reviewed for the first time.
... The first ICLs designed, grown, processed, and characterized at NRL were reported in 2006 [53]. At that time, "W" diode lasers with similar active QWs were operating in pulsed mode at RT [54], albeit with threshold current densities well in excess of 10 kA/cm 2 . The early NRL ICL designs employed "W" active regions, single-QW hole injectors, and relatively thick electron injectors with low doping in four of the wells. ...
... The typical top cladding thickness of 1.5 µm for NRL structures emitting at λ = 4 µm (and assuming thick SCLs) is designed to reduce the nominal loss to < 0.1 cm −1 . Additional loss also occurs if the bottom cladding is too thin, since the mode then leaks into the high-index GaSb substrate [54]. The maximum value of this spectrally-modulated loss is: ...
We review the history, development, design principles, experimental operating characteristics, and specialized architectures of interband cascade lasers for the mid-wave infrared spectral region. We discuss the present understanding of the mechanisms limiting the ICL performance and provide a perspective on the potential for future improvements. Such device properties as the threshold current and power densities, continuous-wave output power, and wall-plug efficiency are compared with those of the quantum cascade laser. Newer device classes such as ICL frequency combs, interband cascade vertical-cavity surface-emitting lasers, interband cascade LEDs, interband cascade detectors, and integrated ICLs are reviewed for the first time.
... The longest wavelength reported so far under CW and RT is a single stage "W" laser emitting at 4.02 tm [21]. ...
A diode laser emitting at mid-infrared wavelength (2~5 pm) is an ideal light source for petrochemical or industrial-important gas sensing. Antimony-based III-V compound semiconductor material is the most prominent pseudomorphic epitaxy candidate for this application. However, phosphide-based material not only has the potential to reach this wavelength utilizing a strained active region but also takes the advantage of sophisticated material study from telecommunication technology. This thesis presents the realization of a 1.97 pm emission ridge waveguide laser in design, fabrication, and characterization phases. Ino.85 Gao.15As/Alo.1Ino.4 8Gao.42As strained multiple quantum wells structures have being built on InP substrates. Structural, optical, and electrical properties of the material have being tested and summarized.
... The tremendous interest in mid-infrared spontaneous emission lies mainly in the fields of industrial trace-gas sensing application [1], environmental pollution control [2], and the inspection of industrial chemical processes. Mostly group III-V [3, 4] and IV-VI semiconductor materials [5 – 7] in the periodic table are pioneers in manufacturing mid-infrared light emitters to meet the application requirements. Easy spectral tunability of emitted light by joule-heating method, comparatively narrower full width ** The author is currently a visiting scholar at the University of Oklahoma. ...
An optimal design of two dimensional (2D) hexagonal photonic bandgap (PBG) resonating micro-optical defect cavity on IV-VI lead salt material has been carried out. The nature of both the transverse electric (TE) and transverse magnetic (TM) band structure for the electromagnetic waves in the periodic triangular lattice pattern is formulated by the well-established plane wave expansion (PWE) method. The defect cavity is engineered to resonate at ~4.17 μm in TM bandgap. The field distribution in the defect cavity has been analyzed based on two very efficient and popular schemes – perturbation correction finite difference (FD) method and finite difference time domain (FDTD) mechanism which is truncated by uniaxial perfectly matched layer (UPML) absorbing boundary condition (ABC). FD method efficiently solves Helmholtz equations to evaluate the field distribution in the semiconducting waveguide for any single spectral wavelength. The numerical results by FD method are re-established by the FDTD scheme that incorporates a precise numerical analysis within a specified wavelength range.
... This type of laser is extensively employed for the monitoring of environmental pollution [2], industrial chemical processes, vehicle exhaust, and other harmful gases. Type I band alignment III-V quantum-cascade lasers [3], GaSb-based type-II quantum-well (QW) semiconductor lasers [4], and IV-VI semiconductor lasers [5]- [7] have been developed in response to these application requirements. Among these leading approaches, IV-VI lasers have the advantage of larger wavelength tunability and a narrow spectral linewidth. ...
The fabrication of an electrically pumped lead salt- based edge-emitting laser on a polished [110]-oriented PbSnSe substrate is presented. The laser structure was grown by molecular beam epitaxy and consisted of a PbSrSe-PbSe multiple quantum- well active region sandwiched between PbSrSe confinement layers. Pulsed laser emission was observed at lambda = 5.2 mum wavelength up to 158 K with a maximum of 40% duty cycle of current pumping. The repeatability in continuous lasing emission power was also examined.
... For such application, high performance MWIR semiconductor laser diodes operating at room temperature (RT) in continuous wave (cw) regime are required with single optical mode emission [1]. Among the different technologies used to achieve this goal, like quantum cascade lasers [2,3] or highly strained type-I Sb-based multi-quantum well (MQW) lasers [4], type-II "W" quantum well lasers grown on GaSb or InAs substrates are very promising [5]. ...
A new class of dilute-nitride laser structure to be grown on InAs substrate is simulated for room temperature emission near 3.3 µm. The active region is composed of several strain-compensated type-II InAsN/GaSb/InAsN quantum wells having the “W” geometry so as to maximized the electron and hole wavefunctions overlap. Optical gain calculations at 300 K show high material gain values, of the order of 1000 cm–1 with injected carrier density of 1 × 1012 cm–2. Radiative current density inferior to 100 A/cm2 is predicted for room temperature operation. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
... For such application, high performance MWIR semiconductor laser diodes operating at room temperature (RT) in continuous wave (cw) regime are required with single optical mode emission [1]. Among the different technologies used to achieve this goal, like quantum cascade lasers [2,3] or highly strained type-I Sb-based multi-quantum well (MQW) lasers [4], type-II "W" quantum well lasers grown on GaSb or InAs substrates are very promising [5]. ...
... Continued improvements in the design of these lasers show the potential for developing continuous-wave (CW), room-temperature (RT) devices across this range. CW emission up to 257 K has been achieved at λ = 3.7 µm, and above RT pulsed operation has been realised at an emission wavelength of 4.02 µm [3][4][5]. A greater understanding of the loss processes which limit the performance of these devices is the primary aim of the work presented here. ...
Using high hydrostatic pressure and spontaneous emission characterisation techniques we have investigated the important loss processes in type-II “W” diode lasers, which emit at 3.24 μm at 78 K. Our studies indicate that Auger recombination involving the excitation of holes in the valence band and/or inter-valence-band absorption may contribute to the temperature sensitivity of these devices, even at cryogenic temperatures. Defect/impurity related recombination, which was of concern in these structures does not appear to make a significant contribution to the threshold current over the temperature and pressure ranges investigated. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
... Each period of the four-layer ''W'' gain region consists of a Ga(In)Sb hole quantum well (QW) surrounded by two InAs electron QWs, which are in turn bounded by AlGa(As)Sb barrier layers. Earlier noncascaded ''W'' diodes demonstrated pulsed lasing at room temperature 6,7 and cw operation to 200 K, 8 while interband cascade lasers with 12-25 stages of the W active region recently lased cw up to 214 K (l 5 3.4 mm) 9 and 223 K (l 5 3.2 mm). 10 The present work reports a series of mid-IR ''W'' diode lasers fabricated from 16 different wafer growths. All of the devices share a common baseline design approach, which was then modified in a vari-ety of ways. ...
... The I-V characteristics also require further attention, although the present devices improve on earlier ''W'' diodes. 7,8,15 The threshold voltages in Table I are well above the theoretical limit (E g /e), and further reduction of the series resistance would substantially impact the maximum cw power that can be generated. This would result in a considerable enhancement of the wallplug efficiency as well as a reduction of the excess heat that must be dissipated. ...
We report an experimental investigation of 16 different mid-infrared diode laser samples with type-II “W” active regions.
A number of design modifications were employed to study effects on the I–V characteristics, lasing threshold, and wallplug
efficiency. Contrary to expectations, the threshold current density at low temperatures did not vary significantly with the
number of active quantum-well periods, nor was there any clear correlation between lasing threshold and photoluminescence
intensity. A shorter-wavelength device (3.2–3.6 µm) produced >500 mW of cw power at 80 K, and a second device displayed a
wallplug efficiency >10%. The maximum lasing temperature was 317 K for pulsed operation and 218 K for cw operation. At T=100
K, cavity-length studies indicated an internal loss of 7 cm−1 and nominal internal efficiency of 96%. Hakki-Paoli measurements of the gain spectrum implied an intrinsic linewidth enhancement
factor of ∼1.3, which slightly exceeds the theoretical prediction. Longer-wavelength devices (λ ≈ 3.8–4.5 µm) showed similarly
low threshold current densities at T=80 K but degraded more rapidly with increasing temperature.
Quantum cascade (QC) lasers are semiconductor light sources based on intersubband (ISB) transitions, that is, electronic transitions between quantized conduction-band states in quantum-wells. As such, their emission wavelength is independent of the specific materials system employed and can be tuned by design over a broad spectral range. Following extensive research efforts, QC lasers have now become the leading semiconductor laser technology for the mid- and far-infrared spectral regions. This chapter begins with an introduction to the basic physics of ISB transitions, followed by a discussion of the key design principles of QC-laser gain media and optical cavities. The main operational parameters, including steady-state, dynamic, and spectral properties, are then described based on a simple rate-equation model. Finally, the performance of current state-of-the-art QC lasers and prospects for further developments are reviewed.
