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Interagency Funded Quantum Well Infrared Photodetector (QWIP) Research and Development at Jet Propulsion Laboratory for NASA and Defense Application
NASA, commercial, medical, and defense applications such as Earth observation systems, astronomy, weather monitoring, thermal mapping, thermography, missile tracking, and night vision aids, etc. require high performance large format long wavelength infrared (LWIR) detector arrays in the range of 8-16 µm.
Long-Wavelength 640 x 486 GaAs/AlGaAs Quantum Well Infrared Photodetector Snap-shot Camera
The performcance of this QWIP camera is reported including indoor and outdoor imaging.
Quantum Well Infrared Photodetectors (QWIPs) for Astronomy
In this paper, we discuss the development of highly uniform longwavelength QWIPs for astronomical applications.
Commercialization of Quantum Well Infrared Photodetector QWIP Focal Plane Arrays
Many commercial and government applications need high performance, large format, long-wavelength infrared (LWIR) detector arrays in the range of 6-20 mu.
PbE (E = S, Se) Colloidal Quantum Dot-Layered 2D Material Hybrid Photodetectors
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Solid state photodetectors and associated optical materials Final report
Solid state photoconductors and associated optical materials
Investigation of responsivity and noise in a direct-coupled photodetector-preamplifier for facsimile cameras
The direct-coupled (DC) mode of detector operation is evaluated for use in a facsimile camera. Photodiode-preamplifier sensitivity is described in terms of photodiode responsivity and possible noise sources resulting from the photodiode and preamplifier. Responsivity and noise limitations are experimentally verified and used to predict photodiode-preamplifier sensitivity under a wide range of operating conditions. Results demonstrate that the DC mode offers advantages in sensitivity and reduced mechanical complexity for facsimile cameras over the more common technique of chopping the radiation and ac amplifying the resultant signal.
Heterojunction III-V alloy photodetectors for high-sensitivity 1.06-micrometers optical receivers
It is pointed out that currently promising technical developments related to the Nd-YAG laser technology at 1.06 micrometers cannot be implemented because of the absence of a suitable detector. Such a detector could possibly be provided in connection with new advances related to the development of the heterojunction III-V alloy photodiode. Details of detector requirements for the considered applications are discussed along with approaches to satisfy these requirements by an appropriate detector design.
Rapid measurements of areal sensitivity and areal spectral response of photodetectors
A flying spot scanning system was used to obtain areal sensitivity and areal spectral response data for nineteen photomultipliers. The efficiency of the electron optics was shown to be dependent upon the type of dynode structure used in the several photomultipliers. From areal sensitivity measurements it was found that the relative spectral response per unit area can vary over the face of a photomultiplier.
A high-precision CdS photodetector for sun sensor applications
A sun detector developed for the Mariner Jupiter/Saturn mission is described. Redundant photopotentiometers for both pitch and yaw axes, positioned below slit apertures, provide spacecraft stabilization and biased operation over plus or minus 20-deg fields of view. The biased (off-sun) operation is required for pointing the 366-cm-diameter (spacecraft-fixed) radio antenna toward earth. Configuration and fabrication processes are presented, along with a summary of development history. Particular attention is given to the properties of cadmium sulfide as these affect adaptation to this application.
Correcting for Nonlinearity in a Photodetector
Simple positive-feedback circuit varies bias voltage as necessary. Ideal detector biased with constant voltage, detector current proportional to photon flux plus constant offset. Detector connected between inverting input and ground, and feedback from operational amplifier through feedback resistor Rf make voltage at inverting input equal to noninverting input. Bias voltage held constant. Principle applied to linearizing mercury cadmium telluride infrared detectors in Fourier-transform spectrometers and other spectral and imaging instruments.
Semiconductor superlattice photodetectors
Technical progress made in the study of superlattice photoconductors is summarized and papers submitted for publication are listed. Since the quantum-well regions may contain several subbands, each of which may be occupied by electrons depending on the doping concentrations, it is important to include the multi-subbands in calculating the impact ionization rate. The electrons occupying the higher subbands require a smaller amount of energy to get out of the quantum well; thus, those higher level subband electrons contribute significantly to the impact ionization rate. The results of the subbands have been calculated. Results concerning the nonparabolicity effect of the band structure, the effect of the quantum-well size, and the effect of the band-edge discontinuity and doping are also summarized.
High frequency GaAlAs modulator and photodetector for phased array antenna applications
A waveguide Mach-Zehnder electro-optic modulator and an interdigitated photoconductive detector designed to operate at 820 nm, fabricated on different GaAlAs/GaAs heterostructure materials, are being investigated for use in optical interconnects in phased array antenna systems. Measured optical attenuation effects in the modulator are discussed and the observed modulation performance up to 1 GHz is presented. Measurements of detector frequency response are described and results presented.
Alternating-Gradient Photodetector For Far Infrared
Proposed detector of photons of wavelengths in range of 30 to 200 micrometer made of alternating layers of lightly and heavily negatively doped germanium. Formed in sequence by conventional chemical-vapor deposition. Alternating-gradient structure enhances collection of photogenerated charge carriers while suppressing dark current, thus achieving high detectivity. Alternating layers of n+ and n- germanium provides high detectivity in far-infrared spectral region. Also possible to make similar structures with positive doping and with other semiconductors as silicon or gallium arsenide to obtain various spectral response.
High frequency GaAlAs modulator and photodetector for phased array antenna applications
A waveguide Mach-Zehnder electro-optic modulator and an interdigitated photoconductive detector designed to operate at 820 nm, fabricated on different GaAlAs/GaAs heterostructure materials, are being investigated for use in optical interconnects in phased array antenna systems. Measured optical attenuation effects in the modulator are discussed and the observed modulation performance up to 1 GHz is presented. Measurements of detector frequency response are described and results presented.