Mid-infrared quantum cascade detectors on InP (original) (raw)

2006, Infrared and Photoelectronic Imagers and Detector Devices II

ABSTRACT We report on the characteristics of two InP-based quantum cascade detectors (QCDs) whose responses are centered at 5.35 and 9 µm. The working principle is based on a vertical intersubband transition followed by a carefully designed extraction cascade, which is adapted to the LO-phonon energy. This device architecture leads to 10 K responsivities R of 8 and 26 mA/W and background limited detectivities D* BLIP of 1.7 x 10 10 and 0.9 x 10 10 jones, for the 5.35 µm and the 9 µm device, respectively. The temperature up to which background limited operation is seen is 115 K for the 5.35 µm device and roughly 65 K for the 9 µm detector. Designed for zero bias operation, QCDs produce a minimal dark current and therefore suffer very little from dark current noise. In addition, capacitance saturation at long integration times can be avoided, making them ideal devices for large focal plane arrays. The 5.35 µm detector was tested at high speed and room temperature. An optical beating signal generated by two slightly de-tuned singlemode quantum cascade lasers was used to test the detector's response at frequencies of up to 23 GHz.

InGaAs∕AlAsSb quantum cascade detectors operating in the near infrared

The authors report on short-wavelength In0.53Ga0.47As/AlAs0.56Sb0.44 quantum cascade detectors QCDs. At room temperature, one device detects at 505 meV (2.46 microns) with a responsivity of 2.57 mA/W, while a second QCD is sensitive at 580 meV (2.14 microns) with a responsivity of 0.32 mA/W.

Mid-Infrared Quantum Cascade Detectors for Thermal Imaging and Environmental Sensors

Proceedings of IRS2

Introduction: There are various photodetector applications in the mid-infrared (MIR) spectral range, both in military and civil applications. Thermal imaging in the MIR is of general interest as the emission of a room temperature black body peaks at a wavelength of 10 µm. Cameras sensitive at this wavelength are thus commonly used in construction to detect thermal bridges, in fire protection to pinpoint pockets of embers, as well as in security and military applications such as missile detection. Dynamic area thermometry is used for breast cancer detection based on the detection of subtle temporal changes of the skin temperature [1]. Heat seeking of hot targets such as aircraft engine exhaust plumes also takes place in the MIR, namely between 3 µm and 8 µm. MIR spectroscopy is an important tool in chemistry and biology, as many molecules and atoms have specific absorption lines between 1 µm and 10 µm. Light detection at 17 µm is of interest for detection of cold interstellar molecular Hydrogen (H2) using heterodyne spectroscopy [2], as the shortest pure rotational line of H2 lies at 17.035 µm [3]. Intersubband (ISB) photodetectors detect in the MIR and are well suited for high speed operation in the GHz range. Due to their narrow linewidth, ISB detectors are a promising choice for molecular and atomar spectroscopy, where often only a small part of the spectrum is of interest. The high speed of ISB detectors makes them interesting for heterodyne spectroscopy in the MIR, which allows to distinguish spectrally close absorption lines. Another pecularity of ISB detectors is that their peak detection wavelength is to a large extent fixed by design and not by material. This allows to engineer narrowband ISB detectors across the whole MIR range.

Mid-IR optical amplification and detection using quantum cascade lasers

Optics express, 2013

Amplification and detection characteristics of mid-infrared quantum cascade lasers (QCLs) are studied. The QCL amplifier has an adjustable bandwidth and tunable gain peak to function as a tunable mid-IR filter. By biasing the QCL slightly below its threshold, we demonstrated more than 11dB optical gain and over 28dB electrical gain at specified wavelengths. In the electrical gain measurement process, the resonant amplifier also functioned as a detector. Mid-IR amplification and detection can be achieved using the same material for the laser source. This indicates that intersubband based gain materials can be ideal candidates for mid-IR photonic integrations.

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