Marcel Caes

Modulation transfer function measurement of an infrared focal plane array by use of the self-imaging property of a canted periodic target

We present a new technique for measuring the modulation transfer function (MTF) of a focal plane array (FPA). The main idea is to project a periodic pattern of thin lines that are canted with respect to the sensors columns. Practically, one aims the projection by using the self-imaging property of a periodic target. The technique, called the canted periodic target test, has been validated experimentally on a specific infrared FPA, leading to MTF evaluation to as great as five times the Nyquist frequency.

Room-temperature electroluminescence in the mid-infrared (2-3 μm) from bulk chromium-doped ZnSe

Electroluminescence associated with impact excitation or ionization of deep Cr(2+) impurity centers in bulk ZnSe is reported. A broad signal of mid-infrared luminescence between 2 and 3 microm is observed once the biased bulk ZnSe device runs into a nonlinear conduction regime. Optical powers in the nanowatt range have been measured at room temperature. The different mechanisms involved in this intracenter infrared light emission are discussed.

Evaluation of the modulation transfer function of an infrared focal plane array using the talbot effect

The purpose of this paper is to describe a new procedure for evaluating the modulation transfer function (MTF) of an infrared focal plane array. This technique is based on the generalized line spread function method in which the MTF is derived from the image of a periodic target consisting of thin lines. The self-imaging property of this kind of object is used to project the target on to the tested focal plane array.

Experimental evaluation of the modulation transfer function of an infrared focal plane array using the Talbot effect

A test bench for measuring the Modulation Transfer Function of an InfraRed Focal Plane Array (IRFPA) is described. The system is based on the use of the self-imaging property of a periodic target made of thin slits for a direct projection of a high-resolution pattern directly on to the tested sensor. The test bench has furnished two different types of experimental results on a specific IRFPA. On one hand, a global method called Canted Periodic Target Test has been developed and applied leading to MTF evaluation up to five times the Nyquist frequency. On the other hand, a local line scanning of every pixel has been made.

Implementation and measurement of gamma radiation on IR photodetectors HgCdTe IRCMOS

For some years, the IR laboratory of ONERA (France) carried out accurate electro-optical characterization on IR detectors. This paper presents some works about IR detector radiation hardness measurements: ONERA, in collaboration with DGA/CEG, measured the effects of gamma radiation on high wavelength IRCMOS. The test conditions respect hard constraints, particularly, during the radiation, detectors were cooled and operating. This paper reviews the implementation of these tests in very hard environment electromagnetic field, radiation, noise ...) and of a test protocol. In spite of severe environmental conditions, quality of measurement is comparable with those done in the laboratory. General component behaviors, transionnal and permanent effects, are summed up for very high dose rate.

SYSIPHE, airborne hyperspectral system: Focus on the SIELETERS thermal hyperspectral imaging instrument

The SYSIPHE system is the state of the art airborne hyperspectral imaging system developed in European cooperation. With a unique wide spectral range and a fine spatial resolution, its aim is to validate and quantify the information potential of hyperspectral imaging in military, security and environment applications. The first section of the paper recalls the architecture of the project. The second one describes the SIELETERS sensors, their implementation onboard the platform and the data processing chain. The last section gives illustrations on the work in progress.

Sieleters, an airbone Imaging Static Fourier Transform Spectrometer: design and preliminary laboratory results

Sieleters is an airborne hyperspectral imager, composed of two cryogenic instruments (MWIR and LWIR), both based on a static interferometer. Its first flight is expected for June, 2013. We present design details and preliminary laboratory results.

Hyperspectral study of a 320x240 uncooled microbolometer array

A test bench has been developed at the ONERA in order to measure the spectral responses of infrared focal plane arrays. This test bench can deliver hyperspectral cartographies with rather good resolutions (better than 16 cm-1) on large spectral ranges (from 1.3 μm to 20 μm). The principle of this test bench will be described and experimental results obtained with a 320x240 uncooled microbolometer array will be presented. As a conclusion, the ability of uncooled microbolometer arrays to make spectral measurements will be discussed.

Modulation transfer function measurement of an infrared focal plane array using a nondiffracting array generator

This paper describes a new test bench for measuring the modulation transfer function of an infrared focal plane array. The system is based on the use of a plane target made of eight gratings that projects in polychromatic light a biperiodic pattern of small and nondiffracting spots called a nondiffracting array.