GaSb-based type I InGaAsSb quantum well mid-infrared (mid-IR) light-emitting diodes (LEDs) operated at wavelengths up to 3.66 µm are demonstrated. The application of quinternary AlGaInAsSb barriers improved hole confinement in the quantum wells and enabled an LED radiant excitance of 1.3 W cm−2 (λ = 3.66 µm) at 100 K which corresponds to the emittance of a blackbody at 1350 K. High-contrast individually addressed 512 × 512 LED arrays were designed and fabricated using wet etching. An accurate characterization technique for mid-IR LEDs has been developed.

The emergence of spectrally multimode smart missiles requires hardware-in-the-loop (HWIL) facilities to simulate multiple spectral signatures simultaneously. While traditional diode-pumped solid-state (DPSS) sources provide a great basic testing source for smart missiles, they typically are bulky and provide substantially more power peak power than what is required for laboratory simulation, have fixed pulse widths, and require some external means to attenuate the output power. HWIL facilities require systems capable of high speed variability of the angular divergence and optical intensity over several orders of magnitude, which is not typically provided by basic DPSS systems. In order to meet the needs of HWIL facilities, we present a low-cost semi-active laser (SAL) simulator source using laser diode sources that emits laser light at the critical wavelengths of 1064 nm and 1550 nm, along with light in the visible for alignment, from a single fiber aperture. Fiber delivery of the multi-spectral output can provide several advantages depending on the testing setup. The SAL simulator source presented is capable of providing attenuation of greater than 70 dB with a response time of a few milliseconds and provides a means to change the angular divergence over an entire dynamic range of 0.02-6 degrees in less than 400 ms. Further, the SAL simulator is pulse width and pulse repetition rate agile making it capable of producing both current and any future coding format necessary.

We have designed and developed dual wavelength type I quantum well light emitting diodes (LEDs) operating at 2 μm and 3–3.4 μm wavelengths with independently controlled intensities. The room temperature quasicontinuous wave output power was 2.8 mW at 2 μm and 0.14 mW at 3 μm. The design of the dual wavelength structure allows for monolithically integrating LED pixels with different wavelengths opening the way for the fabrication of multiwavelength LED arrays for multispectral and hyperspectral imaging applications.

Type I GaSb-based light-emitting diodes (LEDs) have been demonstrated while operating at room temperature at wavelengths up to 3.66 mum with approximately 200 muW of quasi- continuous-wave optical power. A mid-infrared 6 times 6 addressable array of Type I LEDs was also demonstrated.

PurposeThe purpose of this paper is to expand understanding of the current global financial crisis in light of other large‐scale financial crises.Design/methodology/approachThe phenomenon of large‐scale financial crisis has not been modeled well by neo‐classical general equilibrium approaches; the paper explores whether evolutionary and complex systems approaches might be more useful. Previous empirical work and current data are coalesced to identify fundamental drivers of the boom and bust phases of the current crisis.FindingsMany features of financial crisis occur naturally in evolutionary and complex systems. The boom phase leading to this current crisis (early 1980s through 2006) and bust phase (2007‐) are associated with structural changes in institutions, technologies, monetary processes, i.e. changing “meso structures”. Increasingly, purely financial constructs and processes are dominant infrastructures within the global economy.Research limitations/implicationsRigorous analytical predictions of financial crisis variables are at present not possible using evolutionary and complex systems approaches; however, such systems can be fruitfully studied through simulation methods and certain types of econometric modeling.Practical implicationsCommon patterns in large‐scale financial crises might be better anticipated and guarded against. Better money‐liquidity supply decisions on the part of official institutions might help prevent economy‐wide money‐liquidity crises from turning into systemic solvency crises.Originality/valueScholars, policymakers, and practitioners might appreciate the more comprehensive evolutionary and complex systems framework and see that it suggests a new political economy of financial crisis. Despite a huge scholarly literature (organized recently as first‐ second‐ and third‐generation models of financial crises) and a flurry of topical essays in recent months, systemic understanding has been lacking.

Mid-IR (λ≈3–3.5 μm) light emitting diodes with quinternary AlInGaAsSb barriers and InGaAsSb strained quantum wells grown on GaSb substrates have been demonstrated. The devices produced a quasi-cw emission power of 0.7 mW at room temperature and 2.5 mW at T=80 K.

Aerius photonics' has developed a miniature laser rangefinder/altimeter for autonomous navigation and landing in small unmanned aerial vehicles (UAVs). The with a system weight of only 26 grams and a range response from 0 to 100 meters, the unit is capable of insertion into platforms with very small payloads and enables new navigation capabilities previously difficult to achieve.

The next generation of low-cost smart munitions will be capable of autonomously detecting and identifying targets aided partly by the ability to image targets with compact and robust scanning rangefinder and LADAR capabilities. These imaging systems will utilize arrays of high performance, low-cost semiconductor diode lasers capable of achieving high peak powers in pulses ranging from 5 to 25 nanoseconds in duration. Aerius Photonics is developing high-power Vertical-Cavity Surface-Emitting Lasers (VCSELs) to meet the needs of these smart munitions applications. The authors will report the results of Aerius' development program in which peak pulsed powers exceeding 60 Watts were demonstrated from single VCSEL emitters. These compact packaged emitters achieved pulse energies in excess of 1.5 micro-joules with multi kilo-hertz pulse repetition frequencies. The progress of the ongoing effort toward extending this performance to arrays of VCSEL emitters and toward further improving laser slope efficiency will be reported.

Air Force Research Laboratory and North Dancer Labs researchers have completed the initial development and transition to operational use of a high-speed holographic movie system. This paper documents the first fully operational use of a novel and unique experimental capability for high-speed holographic movies and high-speed cinema interferometry. In this paper we document the initial experiments that were performed with the High Speed Holographic Recorder (HSHR) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the possibilities for high-speed cine-laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool. After successful integration and testing the system was delivered to Arnold Engineering Development Center.

Air Force Research Laboratory and MetroLaser, Inc. researchers have completed the initial development and transition to operational use of portable field holography systems. This paper documents the first fully operational use of a novel and unique experimental capability for remote field holography. In this paper we document the field trials and initial experiments that were performed with the Remote Holographic Interferometry System (RHIS) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the effectiveness of remote pulsed laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool.

In this report, we show both theoretically and experimentally how the IR signature of a semiconductor scene (with band gap energy Eg) can be monitored through contactless emissivity control even if this scene thermometric temperature is kept constant. More specifically, we show how a scene emissivity in the spectral band beyond the fundamental absorption range (ω2 < Eg / h, 3 to 5 μm and 8 to 12 μm transparency windows) can be dynamically (frame frequency > 20 kHz) monitored by a shorter wavelength photo excitation of non-equilibrium charge carriers (ω1 > Eg/h, "visible range"). Experimental tests performed on Si and Ge scenes (300 < T < 600 K), demonstrate optically generated cold and hot images and, what is more important, negligible temperature contrast between an object and a background (Stealth effect in IR).

Future types of direct detection LADAR seekers will employ focal plane arrays in their receivers. Existing LADAR scene projection technology cannot meet the needs of testing these types of seekers in a Hardware-In-The-Loop environment. It is desired that the simulated LADAR return signals generated by the projection hardware be representative of the complex targets and background of a real LADAR image A LADAR scene projector has been developed that is capable of meeting these demanding test needs. It can project scenes of simulated two-dimensional LADAR return signals without scanning. In addition, each pixel in the projection can be represented by a "complex" optical waveform, which can be delivered with sub-nanosecond precision. Finally, the modular nature of the projector allows it to be configured to operate at different wavelengths. This paper describes the LADAR Scene Projector and. its full capabilities.