- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A unified figure of merit for interband and intersubband cascade devices
摘要： By exploring a semi-empirical model, the saturation current density J0 is identified to manifest the significant difference in carrier lifetime between interband cascade devices (ICDs) and intersubband quantum cascade devices (QCDs). Based on this model, the values of J0 have been extracted for a large number of ICDs and QCDs from their current-voltage characteristics at room temperature. By analyzing and comparing available ICD and QCD data, we demonstrate how J0 can be used as a unified figure of merit to evaluate both interband and intersubband cascade configurations for their device functionality. The significance of J0 on the performances of mid-infrared detectors and photovoltaic cells is illustrated by comparing the measured detectivity (D*) and the estimated open-circuit voltage (Voc), respectively. From extracted values of J0, which are more than one order of magnitude lower in ICDs than that in QCDs with similar transition energies in active regions, and discussion of the consequences on device performance, the advantages of interband cascade configurations over intersubband quantum cascade configurations have been clearly revealed based on the same framework. The overall picture for both QCDs and ICDs sheds light from the perspective of a united figure of merit, which will provide useful guidance and stimulation to the future development of both ICDs and QCDs.
关键词： Saturation current density,Interband cascade,Quantum cascade,Open-circuit voltage
更新于2025-09-23 15:22:29
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Mid-infrared dual-comb spectroscopy with room-temperature bi-functional interband cascade lasers and detectors
摘要： Interband cascade (IC) laser structures offer attractive potential for operation at room temperature as both broadband coherent sources of mid-infrared light and fast photodetectors. This makes the realization of extremely compact spectrometers on a monolithic platform possible, and even dual-comb spectroscopy (DCS) configurations. IC comb devices are perfect candidates for this configuration, since they develop near-THz-wide optical frequency comb spectra from a millimeter-sized cavity, using a multi-stage structure that can also function as a very fast photodetector. In this work, we leverage IC photodetectors with a gigahertz bandwidth to demonstrate a self-contained, free-running, room-temperature DCS system in the mid-infrared. The DCS system used detection by the same bi-functional IC device structure to measure 1,1-difluoroethane over (cid:2)600 GHz of optical coverage around 3.6 mm. These results show that the IC platform is suitable for full integration as a broadband, high-resolution on-chip spectrometer in a future chemical sensing system.
关键词： mid-infrared,photodetectors,dual-comb spectroscopy,interband cascade lasers,room-temperature
更新于2025-09-23 15:21:01
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Ultrahigh resolution spectroscopy for dimethyl sulfide at the ??1- and ??8-bands by a distributed feedback interband cascade laser
摘要： The ultrahigh-resolution, air-broadened mid-infrared absorption spectrum of dimethyl sulfide (DMS) was recorded in the spectral region of 2994.17–2999.03 cm?1, where the strong ν1-/ν8-bands are located. Benefitting from the tunable laser absorption spectrometry with a distributed feedback interband cascade laser, the spectral resolution achieved 5.69 × 10?6 cm?1. The recorded spectra of DMS are very close to that in the Pacific Northwest National Laboratory (PNNL) database, however it has a much lower absorbance uncertainty of 0.38%. And the maximum relative difference of the full width at half maximum and the integrated area of spectral peaks between the recorded spectra and the PNNL data are as large as 16.7% and 27.9%, respectively, which could mainly come from the difference of the spectral resolution. The more accurate reference spectrum is hopeful to be applied to absolute measurement and remote sensing for gaseous DMS.
关键词： Tunable laser absorption spectroscopy (TLAS),Dimethyl sulfide (DMS),Ultrahigh-resolution spectrum,Interband cascade laser (ICL),Mid-infrared
更新于2025-09-23 15:19:57
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Ppb-level formaldehyde detection system based on a 3.6???μm interband cascade laser and mode-locked cavity enhanced absorption spectroscopy with self-calibration of the locking frequency
摘要： A mid-infrared formaldehyde (H2CO) detection system was demonstrated using a continuous-wave distributed-feedback interband cascade laser (DFB-ICL) emitting at 3.6 μm as light source and an assembly F-P cavity with 20 m effective optical path length as gas chamber. The laser and the cavity were locked to the H2CO absorption peak simultaneously by an electro-optic modulation based automatic Pound-Drever-Hall (PDH) scheme which consist of two steps: dynamic PDH locking and continuous PDH locking. Before continuous PDH locking, the dynamic PDH locking was conducted to acquire the H2CO absorption spectrum and calibration the locking frequency. Then, the cavity transmitted intensity was detected continuously to characterize the gas concentration. H2CO measurements were conducted to evaluate the performance of the sensor system. A linear relationship was observed between the voltage of the absorption signal and the H2CO concentration within the range of 0–6 ppm. Based on Allan deviation analysis, a minimum detection limit of 5.8 ppb was achieved with an averaging time of 30 s.
关键词： Cavity enhanced absorption spectroscopy,Mid-infrared,Interband cascade laser,Formaldehyde detection
更新于2025-09-19 17:13:59
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Performance analysis of narrow-bandgap interband cascade thermophotovoltaic cells
摘要： We present the detailed characterization and performance analysis of two sets of four interband cascade thermophotovoltaic (TPV) devices with InAs/GaSb type-II superlattice (SL) absorbers. The bandgaps of the SL absorbers in the four devices were between 0.22 and 0.25 eV at 300 K. With different numbers of cascade stages and individual absorber thicknesses, we are able to show how possible material quality variations and current mismatch between stages can affect the device performance. Based on the calculated effective quantum efficiency in each stage and experimental results, it is shown that the current mismatch between stages due to the deviation of absorption coefficient from the designed value can be substantial with more stages. On the other hand, the collection efficiency can be much improved with more stages and thin individual absorbers. Also, the carrier lifetime is extracted through measured dark current density to evaluate the material quality. The effects of material quality, current mismatch and collection efficiency on device performance are quantified and a comparison shows that material quality plays the most important role.
关键词： Interband cascade,current mismatch,carrier lifetime,thermophotovoltaic cells
更新于2025-09-19 17:13:59
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High-Speed Mid-Infrared Interband Cascade Photodetector Based on InAs/GaAsSb Type-II Superlattice
摘要： High-speed mid-wave infrared (MWIR) photodetectors have applications in the areas such as free space optical communication and frequency comb spectroscopy. However, most of the research on the MWIR photodetectors have been focused on how to increase the quantum efficiency and reduce the dark current, in order to improve the detectivity (D*), and the 3dB bandwidth performance of the corresponding MWIR photodetectors is still not fully studied. In this work, we report and characterize a MWIR interband cascade photodetector based on InAs/GaAsSb type-II superlattice with a 50% cutoff wavelength at ~5.3 μm at 300 K. The 3 dB cutoff frequency is 2.4 GHz at 300 K, for a 40 μm circular diameter device under -5 V applied bias. Limitations on the detector high-speed performance are also discussed.
关键词： high-speed photodetector,mid-wave infrared photodetector,Interband cascade infrared photodetector
更新于2025-09-16 10:30:52
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Type-II superlattice photodetectors versus HgCdTe photodiodes
摘要： The development of the HgCdTe alloy as the most important intrinsic semiconductor for infrared (IR) technology is well established and recognized. In spite of the achievements in material and device quality, the drawbacks still exist due to bulk and surface instability, lower yields and higher costs particularly in fabrication of long wavelength infrared arrays. The dif?culties with this material encouraged to research on other compounds to improve device performance. Since the ?rst paper published by Sakaki and Esaki in 1978 it is well known that InAs and GaSb constitute a nearly lattice-matched material system offering great ?exibility in the design of IR optoelectronic devices. After four decades, the III-V type-II superlattice (T2SL) detector technology is under strong development as a possible alternative to HgCdTe. The novel ideas coming in design of detectors have enhanced the position of T2SLs in IR materials detector technology. It appears that T2SLs are especially helpful in the design of unipolar barriers. In this paper fundamental physical properties of two material systems, HgCdTe and T2SLs, are compared together with their in?uence on detector performance: dark current density, RA product, quantum ef?ciency, and noise equivalent different temperature. In comparison with HgCdTe, fundamental properties of T2SLs are inferior. On the other hand, T2SL and barrier detectors have several advantages to include lower tunnelling and surface leakage currents, and suppressed Auger recombination mechanism. Up to date, the promise of superior performance of these detectors has not been realized yet. In the paper we present that the performance of T2SL detectors (dark current, current responsivity, and noise equivalent difference temperature) is lower than bulk HgCdTe photodiodes. Due to stronger, less ionic chemical bonding of III-V semiconductors, these materials are attractive due to manufacturability and stability. It is also predicted that the interband T2SL quantum cascade devices will outperform the performance of the high operating temperature HgCdTe detectors.
关键词： Type-II superlattices,Responsivity,HgCdTe,Operability,Dark current,Interband cascade infrared detectors,Carrier lifetime
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Rate Equation Modeling of Interband Cascade Lasers
摘要： Interband cascade lasers (ICLs) are power-efficient mid-infrared laser sources for applications in sensing of numerous molecules and in free-space optical communications. The static performances of ICLs including the lasing threshold and the output power have been significantly improved since its first demonstration by R. Yang [1]. GaSb-based ICLs have optimal performance in the spectral range of 3-4 μm, which is hard to reach for the quantum cascade laser counterpart [2]. This work proposes a rate equation model for studying dynamical characteristics of ICLs including the intensity modulation (IM) response, the relative intensity noise (RIN), and the frequency noise (FN). Taking into account carrier dynamics in the W-shape active region while ignoring those in the electron and hole injectors [3], the rate equations for the carrier number N, the photon number S, and the phase φ of the electric field read. Based on the standard small-signal analysis of the above rate equations, we obtain analytical formulas for IM response, RIN, and FN, respectively (not shown in this paper). The inset of Fig. 1(a) shows that ICLs exhibit an underdamped resonance peak in the IM response at a low pump current, and the modulation bandwidth increases with increasing pump current as conventional laser diodes. Figure 1(a) proves that more gain stages are desirable for enhancing the modulation bandwidth of ICLs. The inset of Fig. 1(b) shows that the RIN is raised at the resonance frequency, while a small stage number reduces the RIN in the whole spectral range. Figure 1(b) demonstrates that the RIN at the low-frequency range (<1.0 GHz) increases nonlinearly with the gain stage number. The inset of Fig. 1(c) shows that the FN of ICLs is raised at the resonance frequency, while a small stage number reduces the FN in the whole spectral range as well. The intrinsic spectral linewidth of ICLs in Fig. 1(c) is obtained from the low-frequency FN level. It is found that the intrinsic linewidth linearly increases with the gain stage number, which is consistent with the derived analytical formula. In summary, we theoretically prove that a large gain stage number is desirable for enhancing the modulation bandwidth, while a small stage number is favorable to reduce both the RIN and the FN/linewidth of ICLs.
关键词： Interband cascade lasers,rate equation model,frequency noise,intensity modulation,relative intensity noise
更新于2025-09-12 10:27:22
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Linewidth broadening factor of an interband cascade laser
摘要： This work reports the linewidth broadening factor (LBF) of a continuous-wave interband cascade laser operated both below and above threshold. Using the Hakki-Paoli method, the below-threshold LBFs around the gain peak are determined to be in the range of 1.1–1.4, where the thermal effect is carefully removed. Employing the self-mixing interferometry technique, the above-threshold LBFs are measured to be around 2.2, which do not increase with increasing pump current.
关键词： linewidth broadening factor,interband cascade laser,Hakki-Paoli method,self-mixing interferometry
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Ring Interband Cascade Lasers for Environmental Monitoring
摘要： Interband cascade lasers (ICLs) combine the concept of quantum cascade lasers (QCLs) and conventional photodiodes, because they rely on the voltage-efficient in-series connection of multiple active regions as in QCLs as well as the long upper-level recombination lifetimes of photodiodes. The distinctive low power consumption of ICLs makes them especially attractive for mobile applications in the mid-infrared, such as process control, medical applications and spectroscopy. As a first proof of principle we present ICLs fabricated into ring-shaped cavities. A second order distributed feedback (DFB) grating is used for the light outcoupling of our ring ICLs, in vertical direction through the GaSb substrate. The first demonstrated devices with a waveguide width of 10 μm and 400 μm outer diameter show light emission at a wavelength of ~3.7 μm. A pulsed threshold current density <1 kA/cm2 is measured at 20°C. We are currently working on the second generation of such ring ICLs with smaller waveguides for better suppression of higher order lateral modes and larger outer diameter (e.g. 800 μm) for increased optical output power. The newly developed devices are used in a project for trace gas sensing via the principle of photothermal interferometry.
关键词： Interband cascade lasers,trace gas sensing,distributed feedback grating,photothermal interferometry,ring-shaped cavities
更新于2025-09-12 10:27:22