Dynamic Infrared Scene Projector Research Articles

Photoinduced opaque effect model for light down-converter of dynamic infrared scene projection

Dynamic infrared scene projection is a technology for converting infrared (IR) digital image sequences into IR radiating image sequences. One of the most promising technologies is light down-conversion technology based on photoinduced opaque (PIO) effect. A parametric end-to-end steady-state model was proposed to describe the PIO mechanism. It consisted of three submodels such as the silicon parameter model, the photoinduced free carrier model, and the constitutive relation model. Furthermore, the parametric full-link from pump photons’ power density, photoinduced free carrier concentration, complex dielectric constant, and complex refractive index to the emissivity was constructed and mathematically analyzed by the above model. In order to verify the model, an intrinsic silicon wafer was pumped by a continuous-wave running Nd:YAG laser when the wafer was heated up to 321, 423, 459, and 498 K, respectively. Correspondingly, the emissivity integrated from 3 to 5 μm, with the increase of the pump power density measured by an IR camera. The measurement result agreed well with the theoretical result computed by the parametric end-to-end steady-state model. The maximum apparent temperature of the region illuminated by the laser with a pump power density of 407 W cm − 2 is up to 453 K when the silicon wafer was kept at 498 K. At the same time, the background temperature was elevated to 330 K owing to the initial free-carrier absorption enhancement.

红外捕获跟踪设备辐射式仿真试验技术研究

The radiation simulation system for IR acquisition and tracking device were introduced based on the DMD dynamic infrared scene projector. The optical principle of the DMD projector was introduced. The requirements and methods of the optical matching between the DMD projector and system under tested were analyzed. The time modulation of the DMD projector was introduced, and the requirements and methods of the synchronization between the DMD projector and system under tested were analyzed. The factors which influence on the energy transmission between DMD projector and system under tested were analyzed, and the methods of calibration and energy matching between DMD projector and system under tested were analyzed. The experiments were carried out for certain IR acquisition and tracking device using the simulation system, and some performance of the device were simply assessed.

Bulk silicon as photonic dynamic infrared scene projector

A Si-based fast (frame rate >1 kHz), large-scale (scene area 100 cm2), broadband (3–12 μm), dynamic contactless infrared (IR) scene projector is demonstrated. An IR movie appears on a scene because of the conversion of a visible scenario projected at a scene kept at elevated temperature. Light down conversion comes as a result of free carrier generation in a bulk Si scene followed by modulation of its thermal emission output in the spectral band of free carrier absorption. The experimental setup, an IR movie, figures of merit, and the process's advantages in comparison to other projector technologies are discussed.

Infrared negative luminescent devices and higher operating temperature detectors

Infrared LEDs and negative luminescent devices, where less light is emitted than in equilibrium, have been attracting an increasing amount of interest recently. They have a variety of applications, including as a ‘source’ of IR radiation for gas sensing; radiation shielding for, and non-uniformity correction of, high sensitivity staring infrared detectors; and dynamic infrared scene projection. Similarly, infrared (IR) detectors are used in arrays for thermal imaging and, discretely, in applications such as gas sensing. Multi-layer heterostructure epitaxy enables the growth of both types of device using designs in which the electronic processes can be precisely controlled and techniques such as carrier exclusion and extraction can be implemented. This enables detectors to be made which offer good performance at higher than normal operating temperatures, and efficient negative luminescent devices to be made which simulate a range of effective temperatures whilst operating uncooled. In both cases, however, additional performance benefits can be achieved by integrating optical concentrators around the diodes to reduce the volume of semiconductor material, and so minimise the thermally activated generation-recombination processes which compete with radiative mechanisms. The integrated concentrators are in the form of Winston cones, which can be formed using an iterative dry etch process involving methane/hydrogen and oxygen. We present results on negative luminescence in the mid- and long-IR wavebands, from devices made from indium antimonide and mercury cadmium telluride, where the aim is sizes greater than 1 cm×1 cm . We also discuss progress on, and the potential for, operating temperature and/or sensitivity improvement of detectors, where very high-performance imaging is anticipated from systems which require no mechanical cooling.

Dynamic infrared scene projection: a review

Since the early 1990s, there has been major progress in the developing field of dynamic infrared scene projection, driven principally by the need for hardware-in-the-loop simulation of the oncoming generation of imaging infrared missile seekers and more recently by the needs for realistic simulation of the new generation of thermal imagers and forward-looking infrared systems. In this paper the current status of the dynamic infrared projection field is reviewed, commencing with an outline of its history. The requirements for dynamic infrared scene projection are examined, allowing a set of validity criteria to be developed. Each class of infrared projector that has been investigated—emissive, transmissive, reflective, laser scanner and phosphor—together with the specific technology initiatives within the class is described and examined against the validity criteria. In this way the leading dynamic infrared scene projection technologies are identified.

Applications of negative luminescence

The application of non-equilibrium transport techniques to narrow-gap semiconductor materials has produced practical, negative luminescent devices. These structures contravene Kirchhoff's law because they will absorb infrared radiation in a limited band without emitting it. They have many potentially important applications which include toxic gas sensing, cold shields for IR detectors, radiometric reference sources and dynamic infrared scene projectors.

Review of infrared scene projector technology-1993

The importance of testing IR imagers and missile seekers with realistic IR scenes warrants a review of the current technologies used in dynamic infrared scene projection. These technologies include resistive arrays, deformable mirror arrays, mirror membrane devices, liquid crystal light valves, laser writers, laser diode arrays, and CRTs. Other methods include frustrated total internal reflection, thermoelectric devices, galvanic cells, Bly cells, and vanadium dioxide. A description of each technology is presented along with a discussion of their relative benefits and disadvantages. The current state of each methodology is also summarized. Finally, the methods are compared and contrasted in terms of their performance parameters.

Electron-beam-addressed membrane mirror light modulator for projection display

The performance of a prototype, reflection-mode projection display based on an electron-beam-addressed membrane mirror light modulator (e-MLM) is described. The e-MLM converts electronic video information into a two-dimensional phase object, that is then schlieren imaged onto a screen. High-contrast dynamic projection of images is demonstrated over a broad range of wavelengths, from the visible to the midinfrared. As such this device is expected to find applications in large-screen visible displays and dynamic infrared scene projectors.