Modeling of an infrared stationary micro-spectrometer integrated on a focal plane array

During the last few years, considerable efforts have been made in developing innovative spectrometric techniques at ONERA [1,2]. These instruments are dedicated to applications such as measurements of chemical agents spectral signatures, high temperature gas or objects at room temperature. There is therefore a real need for dedicated technology, as well as embedded processing modules able to extract the radiometric physical parameter from a raw signal. In this paper, a modeling approach for a static infrared spectrometer, Microspoc, is discussed in order to obtain good quality spectra

Dazzling sensitivity analysis of a microbolometer array on an infrared laser irradiation breadboard

International audienceLaser sources have evolved towards lower cost and higher power, and the risk of imaging system disturbance due to laser dazzling effects can no more be ignored. In this paper we first present an experimental bench which has been developed specifically to perform dazzling experiments on infrared focal plane arrays. With this breadboard, dazzling experiments have been conducted on various types of focal plane arrays. We will focus on results obtained on a standard microbolometer array. The main parameters affecting dazzling phenomena were varied and conclusions on the dazzling phenomena are proposed. Since the major impact of laser pulses on microbolometer focal plane is due to heating, a first and simple phenomenological model of laser dazzling of these uncooled detectors is presented. Moreover thanks to the high level of performance of this breadboard, a new method is described for the direct measurement of the thermal time constant of the microbolometer array

High acquisition rate infrared spectrometers for plume measurement

International audienceFor a few years, Onera has developed static Fourier transform spectrometers. These spectrometers are napshot and benefit from a high étendue, thus making them well suited for measuring fast moving scenes, such as rocket plumes. In particular, Onera has developed two cryogenic infrared instruments, Mistere and Microspoc, which can measure spectra at a high repetition rate (few hundred of Hertz), on a wide spectral range ([2.9μm ; 9.6μm] and [1.5μm ; 5μm]), and with a moderate spectral resolution (15cm-1 and 30cm-1). The design of these spectrometers will be presented, as well as examples of experimental results

Overview of alternative infrared detectors and focal plane arrays for LWIR applications

For a variety of scientific, space and defence applications, there is an increasing demand for long-wavelength infrared (LWIR) detector focal plane arrays and compact infrared instruments. In the first part, we present an overview of alternative detectors to standard mercury cadmium telluride photodiodes for LWIR detection, such as the HgCdTe avalanche photodiode, the quantum-well infrared photo-detectors, the superlattice detectors and the carbone nanotubes-based bolometers. In the second part, we focus on new concepts developed to meet the requirement of miniaturization of infrared instruments. Original IRFPA-based micro-optical assemblies have been achieved, demonstrating several optical functions such as imagery, spectral filtering, spectrometry and wavefront sensing

Publisher Correction: Control of laser plasma accelerated electrons for light sources

The original version of this Article contained an error in the last sentence of the first paragraph of the Introduction and incorrectly read ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime in equation 11, nx(n-β) x β: n the two times and beta the two times should be bold since they are vectorsin Eq. 12, β should be bold as well.’ The correct version is ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime.’This has been corrected in both the PDF and HTML versions of the Article

Tunable High Spatio-Spectral Purity Undulator Radiation from a Transported Laser Plasma Accelerated Electron Beam

International audienceUndulator based synchrotron light sources and Free Electron Lasers (FELs) are valuable modern probes of matter with high temporal and spatial resolution. Laser Plasma Accelerators (LPAs), delivering GeV electron beams in few centimeters, are good candidates for future compact light sources. However the barriers set by the large energy spread, divergence and shot-to-shot fluctuations require a specific transport line, to shape the electron beam phase space for achieving ultrashort undulator synchrotron radiation suitable for users and even for achieving FEL amplification. Proof-of-principle LPA based undulator emission, with strong electron focusing or transport, does not yet exhibit the full specific radiation properties. We report on the generation of undulator radiation with an LPA beam based manipulation in a dedicated transport line with versatile properties. After evidencing the specific spatio-spectral signature, we tune the resonant wavelength within 200–300 nm by modification of the electron beam energy and the undulator field. We achieve a wavelength stability of 2.6%. We demonstrate that we can control the spatio-spectral purity and spectral brightness by reducing the energy range inside the chicane. We have also observed the second harmonic emission of the undulator

Control of laser plasma accelerated electrons for light sources

Electron beam quality in accelerators is crucial for light source application. Here the authors demonstrate beam conditioning of laser plasma electrons thanks to a specific transport line enabling the control of divergence, energy, steering and dispersion and the application to observe undulator radiation

Publisher Correction: Control of laser plasma accelerated electrons for light sources

The original version of this Article contained an error in the last sentence of the first paragraph of the Introduction and incorrectly read ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime in equation 11, nx(n-β) x β: n the two times and beta the two times should be bold since they are vectorsin Eq. 12, β should be bold as well.’ The correct version is ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime.’This has been corrected in both the PDF and HTML versions of the Article

An application of laser–plasma acceleration: towards a free-electron laser amplification

International audienc