In recent years, an interest in the detection of the ShortWave Infra-Red (SWIR) band has grown. On the ground, the development of telescopes (ELTs) requires the construction of large focal planes in the SWIR for imaging, spectroscopy, or wavefront sensing applications. In space, the SWIR band can have many applications whether for communications or for imaging space and earth. The state-of-the-art III-V detectors in the SWIR are InGaAs photodiodes on InP substrate that are limited by a 1.7μm cut-off wavelength. Superlattice (SL) based detectors, that have been increasingly studied in recent years, make it possible to reach new cut-off wavelengths. Starting from the InGaAs on InP detector technology that has been mastered for more than ten years by THALES, the III-V Lab we propose to extend the detection range beyond 1.7μm by introducing a SL in the active region of an InGaAs photodiode. We will present the results obtained up to 2.6μm, as well as the solutions implemented to limit the carrier localization in the superlattice and the associated QE degradation. We will also discuss the consequence of minority carrier lifetime on the performance and the consequence of localization on MTF.
In recent years, an interest in the detection of the Short Wave Infra-Red (SWIR) band has grown. In these wavelengths, we benefit both from the properties of the visible and thermal infrared, offering new information and a different contrast to the image. In the defense field, this band offers the possibility of passive and active imaging, as well as the detection of laser or thermal radiation from bodies above ambient temperature. The state-of-the-art III-V detectors in the SWIR are InGaAs photodiodes on InP substrate that are limited by a 1.7 μm cut-off wavelength. Super-lattice (SL) based detectors, that have been increasingly studied in recent years, make it possible to reach new cut-off wavelengths. Starting from the InGaAs on InP detector technology that has been mastered for more than ten years by THALES, the III-V Lab we propose to extend the detection range beyond 1.7 μm by introducing a SL in the active region of an InGaAs photodiode. We will present the results obtained up to 2.5 μm, as well as the solutions implemented to limit the carrier localization in the super-lattice and the associated QE degradation.
This paper presents a new concept of frequency comb LIDAR instrument for atmospheric CO2 mapping. The French space agency (CNES) has initiated the development of an airborne proof of concept. The main originality of this instrument lies in the use of two probe combs crossing the same atmospheric path and used for self-phase correction. This technique, named Double Heterodyne Detection (DHD), allows us to coherently average interferograms beyond the coherence time of the laser source. The LIDAR airborne instrument is designed for real-conditions atmospheric CO2 measurements at 1.572 μm and mainly relies on commercial telecom components. We present experimental results on a breadboard laboratory version of the instrument and our data processing method. Then, we extend the study to a space instrument and provide a first estimation of radiometric performances.
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