U.S. Air Force Research Lab Summer Faculty Fellowship Program

U.S. Air Force Research Lab Summer Faculty Fellowship Program

U.S. Air Force Research Lab Summer Faculty Fellowship Program

AFRL/RD (Kirtland Air Force Base, New Mexico )

SF.10.21.B0001: non-linear Wavefront Sensing

Mateen, Mala - 505-846-0464

Program/Topic: Closely Spaced Object Detection/High Sensitivity Wavefront Sensing.
Abstract/Content:There is a gap between the fundamental limit at which wavefront sensing can be performed and the ground-based assets available to the AFRL to carry out wavefront sensing for SSA needs. This gap can be bridged by using wavefront sensors that fully utilize the spatial coherence of the aperture and are able to sense low spatial frequencies that dominate 70% of the atmospheric turbulence.
The non-linear curvature wavefront sensor is able to effectively sense low and high spatial frequencies in a photon starved environment allowing for high contrast imaging at a few lambda/D separation. We want to explore developing and implementing the non-linear Curvature Wavefront Sensor in the lab and on a telescope.

SF.10.20.B0004: Unconventional imaging, wavefront sensing, and adaptive optics

Spencer, Mark - 951-323-3374

Current imaging, wavefront-sensing, and adaptive-optics solutions are inadequate when in the presence of distributed-volume atmospheric aberrations and extended objects (aka the "deep-turbulence problem"). This shortcoming requires that we innovate towards new solutions. In leveraging a recent journal-article publication [https://doi.org/10.1364/JOSAA.36.000A20], this research opportunity will continue to develop imaging, wavefront-sensing, and adaptive-optics solutions that sense and correct for the disturbances found along the propagation path. Such solutions will enable advanced remote-sensing and directed-energy functions at extended standoffs.

SF.10.20.B0003: Wavefront Sensing Testbed

Mateen, Mala - 505-846-3950

In the astronomical world pyramid wavefront sensors (PWFS) have already proven to be high sensitivity wavefront sensors, to be used with Natural Guidestar adaptive optics system, which deliver high contrast images of exoplanets close to their parent stars. With the help of the PWFS academic institutions have imaged never-before-seen exo-planets around stars, such as HR8799.
We seek to leverage the technology developed by the astronomical community to enhance our capability to detect dim objects close to brighter high-value assets. To help the AFRL with this effort we would seek collaborators to spend a summer at the Starfire Optical Range where we will be integrating, aligning, and testing the PWFS. The objective is to build and implement a pyramid reconstructor so that we can close the adaptive optics loop using the PWFS and compare its performance with other wavefront sensors.

SF.10.20.B0002: Development of NIR and MIR active ion doped glasses

Henry, Leanne - 505-846-9302

Both near infrared (NIR) and mid infrared (MIR) optical materials are investigated in the novel materials lab with the aim of developing new laser materials emitting at novel wavelengths. The NIR thrust involves the investigation of bismuth doped glasses for laser applications between 1200-1500 nm and 1600-1800 nm. The research involves development of fabrication processes to enable luminescence in the wavelength range of interest as well as optimization of the gain bandwidth. This may involve the utilization of co-dopant ions and the study of energy transfer processes. The work will also involve the characterization of the optical material in the laboratory via luminescence, absorption, and lifetime. Also, Raman spectroscopy and X-ray diffraction are available at a local facility. Once an optimized composition has been arrived at, optical fiber can be prepared by the powder-in-the-tube method and drawn either on a local draw tower or at a contractor facility. Relative to the MIR thrust, the aim is the development of a tunable emitter in the 4 micron range. The hope is that this can be accomplished via a nanocrystal doped glass. The main focus of this project is the successful placement of nanocrystals into a MIR glassy material at varying concentration levels followed by characterization of the material via absorption, luminescence, lifetime, and X-ray diffraction. If a promising material is developed, an optical fiber will be fabricated and investigated relative to its ability to propagate light, losses, and laser efficiency. To conclude, the research carried out in this laboratory is at the fundamental / basic level. The end goal is the development of the next generation of laser materials to enable lasers at new wavelengths in addition to improving the efficiency of existing material systems.

SF.10.20.B0001: Optical and Thermo-mechanical performance characterization of novel ceramic materials under high energy laser illumination

Morley, Nick - 505-846-0805

This research topic will investigate ceramic materials made of ZrB2 and SiC for use in the high energy laser (HEL) applications. These materials show great promise for use as HEL mirror face sheets due to their intrinsic stiffness, thermal stability, and low density. The researcher will leverage Air Force Research Lab Directed Energy Directorate`s optics damage laboratory and optical measurement resources to explore the overall response of these novel lightweight materials and then feedback the understanding gained from the effort back into the material design process for second generation ceramic development.

SF.10.19.B0001: AFRL New Mexico Tech Engagement Office

Fetrow, Matthew - 505-620-5204

The AFRL New Mexico Tech Engagement Office (AFRL/RDMX) supports the AFRL Directed Energy Directorate (RD) and Space Vehicles Directorate (RV) in the following areas: Technology Transfer, Economic Development, Small Business Outreach and Media Relations/Corporate Communications. Areas of interest include: Federal Laboratory intellectual property processes as well as Patent License Agreement, Cooperative Research and Development Agreement (CRADA), Education Partnership Agreement, Commercial Test Agreement, Information Transfer Agreement, and Material Transfer Agreement opportunities.

SF.10.19.B0001: AFRL New Mexico Tech Engagement Office

Fetrow, Matthew - 505-620-5204

The AFRL New Mexico Tech Engagement Office (AFRL/RDMX) supports the AFRL Directed Energy Directorate (RD) and Space Vehicles Directorate (RV) in the following areas: Technology Transfer, Economic Development, Small Business Outreach and Media Relations/Corporate Communications. Areas of interest include: Federal Laboratory intellectual property processes as well as Patent License Agreement, Cooperative Research and Development Agreement (CRADA), Education Partnership Agreement, Commercial Test Agreement, Information Transfer Agreement, and Material Transfer Agreement opportunities.

SF.10.17.B0001: Rayleigh beacon adaptive optics on a small telescope

Johnson, Robert - (505)-846-6699

AFSPACE needs affordable, small, portable telescopes for space situational awareness applications, such as distinguishing closely spaced objects at low-Earth orbits up to geosynchronous-Earth orbit. This research topic would model, design, and build a Rayleigh beacon adaptive optics system for a 1-m telescope. Candidates would have a background in laser beacon adaptive optics and would have at least a secret clearance (or could receive one before starting). They must also be a U.S. citizen.

SF.10.13.B1205: Modeling studies of complex nonlinear systems for defense applications

Bochove, E - (505) 846-4639

Participants in the program are expected to perform analysis of complex nonlinear systems, the nature of which is subject to his or her choice.

Topics of special interest will be given priority, such as, for example: atmospheric propagation of laser arrays through deep turbulence with application to targeting and destroying enemy missiles; modeling of biological and physiological systems, including sensory and cognitive behaviors of the central neural system; pattern recognition; the spread and control of pandemics; the treatment of disease by medication, radiation or other therapies; ecological and environmental studies, including predictions of climate change and its effects; political, social and economic system modeling, etc.

New mathematical and/or computational methods are sought, e.g. based on neural-net techniques, but the features in the models of nonlinearity, feedback, scaling capacity and complexity, massive interconnectivity, or others relevant to the proposed subject, are desired. Phenomena of interest include bifurcations and instabilities, chaos, and self-organization, but mathematical models should be founded on empirical precedent.

SF.10.03.B9101: Simulation of Plasmas and High Power Microwave Devices

Mardahl, P - (505) 846-8571

The Air Force Research Laboratory is at the forefront of high-performance computing for the Department of Defense. The High Power Microwave Division has a solid record of developing plasma and electromagnetic simulation software. Researchers use these codes to investigate various concepts involving collisional and collisionless plasmas, in collaboration with investigators at other laboratories to help design and diagnose a variety of experiments. The HPM Division has access to some of the most advanced high-performance parallel computing platforms available, including machines with 1000s of CPU. Over the past few years, the division has developed portable, parallel, three-dimensional plasma physics simulation codes for complex geometries, using particle-in-cell (PIC), multi-fluid, and hybrid approaches.

Our principal goal is to improve the state-of-the-art of plasma physics simulations to enable virtual prototyping of high-power microwave devices. As advanced Air Force weapons concepts move from the laboratory to the field, the size of the packages must generally decrease. This effective decrease in the characteristic length scale increases the relative importance of diffusive processes compared to convection. We seek applicants with strong backgrounds in physics and the application of large-scale scientific computation for plasmas and charged-particle beams that interact with complex structures.

SF.10.03.B6642: Algorithm and Theory Development for the Simulation of Novel Directed Energy Devices

Garrett, Travis - (505) 853-4320

Numerical modeling plays a key role in the research of next generation directed energy devices at the AFRL. Our goal is to increase the predictive power of simulations through advances in both algorithms and physical theory. Directed energy subjects of interest include variants of classic High Power Microwave (HPM) devices such as relativistic magnetrons, vircators and backwards wave oscillators, to the exotic physics of Ultra-Short Pulse Lasers (USPLs) which can produce RF via atmospheric filaments and GeV scale particles through Plasma Wake Field Acceleration (PWFA), to new ferrite based Non-Linear Transmission Lines (NLTLs) and the evolution of relativistic particle beams and their interactions with matter. The development of high order conformal methods for both metals (including Surface Impedance Boundary Conditions) and dielectrics to increase the speed and accuracy of simulations is of great interest, as it the adaptation of our current Particle-In-Cell (PIC) code to massively parallel GPU architectures that include Adaptive Mesh Resolution (AMR). Improved physics models and algorithms are needed to capture the processes taking place inside HPM devices, including plasma formation at both cathodes and anodes (including possible anomalous transport), secondary emission and multipactor, and air breakdown. Progress in theory and numerical methods is also needed to model and understand the novel physics of USPLs, including long range nonlinear propagation and strong field ionization to non-Maxwellian strongly coupled plasmas and the generation of Surface Plasmon Polaritons (SPPs). US Citizen Only

SF.10.03.B5387: Effects on Radio Frequency (RF) Radiation on Electronics

Clarke, T.J - (505) 846-9107

Our research focuses on modeling the interaction between continuous wave (CW) and pulsed radio frequency (RF) fields and analog and digital electronics. This includes large scale finite difference time domain (FDTD) modeling of the propagation of RF energy to an electronic device and the internal field structure that is established, as well as modeling the coupling of energy to cables and electronic components and circuit traces. It also includes predicting the effect of this coupled RF energy on the functioning of the electronic circuit. In addition, we are interested in modeling effects on large scale electronic systems comprising very large numbers of such circuits. This research involves performing electromagnetic modeling, as well as building new models describing the interaction with electronics and comparing the results from these models with experimental data to validate and improve the models.

SF.10.03.B4500: Analysis of Strong Turbulence Effects on Laser and Speckle Propagation

Gudimetla, Venkata - (808) 891-7750

Although strong atmospheric turbulence is often encountered in many space (low elevation angles) and horizontal paths, no large efforts were made to analyze the problem critically via analytical approaches. Simulations based on phase screen approaches have been done and some mitigation methods have been invented. Some work has been done in characterizing the moderately strong optical turbulence and its effects on the histograms of the intensity. But no efforts were made to arrive at analytical expressions for various optical system parameters in deep turbulence. This field was active in late1970s and early 1980s and since then, no publications have appeared except in the subtopic of the fluctuations of intensity and some related efforts such as coherence length. Hence, to develop a clear understanding of the problem and to optimize the methods of mitigating the strong turbulence effects in such important applications as space based imaging and the design of adaptive optics systems, a critical examination of various phenomena in strong turbulence in spatial, temporal and related spectral domains is needed. Here, we propose to examine the role of Kolmogorov spectral wave numbers in affecting the various important optical parameters such as Fried coherence length, isoplanatic angle, spectra of figure and tilt and several other optical parameters and use this information to develop analytical expressions. We expect that the resulting expressions to be multi-dimensional integrals and will use USAF super-computing resources available locally to calculate the results and complete the problem by comparing the data with simulations from the phase screen approach and experimental data if needed. This analysis work supports several on-going projects in space imaging, sodium guidestar beacons and related problems and deep turbulence mitigation. Emerging techniques such as statistical estimation methods will be encouraged.

SF.10.02.B9076: Advanced Gas Lasers and High Performance Computing Simulation of Multi-Physics

Madden, T.J - (505) 846-9076

This research is comprised of the physical processes that underlie gas lasers: laser physics, optics, physical chemistry, spectroscopy, and fluid dynamics. Gas lasers use various mechanisms for generating a population inversion within the gas: chemical reactions, electric discharges, rapid gas dynamic expansion, and optically pumping. As a part of the generation of the population inversion, chemical kinetic processes may support or erode the inversion, having a significant impact upon laser performance in conjunction with spontaneous and stimulated emission of photons. Spectroscopy plays an important role here with broadening processes associated with the lineshape of the lasing transmission, measurement of intermediate species populations, determination of gas temperature, and visualization of the flow structure providing critical roles. With a population inversion in place, lasing action occurs with the optical physics interplay with the laser gain generated in the gas media dictating power extraction from the gas. Stable and unstable resonator configurations are used with novel resonator configurations being of interest. As all of these processes occur within a gas, fluid dynamics play a critical role with flow stability, unsteadiness, and transition in subsonic through supersonic flows from very low to high Reynolds numbers being significant. Research opportunities exist related to all of the above areas in both experimental and theoretical capacities. Within the theoretical discipline, modeling of these complex physical processes utilizing high performance computing on very large parallel architectures is a significant activity with research opportunities in the various associated disciplines being available.

SF.10.02.B4707: High Performance Compact Pulsed Power Components

Heidger, S.L - (505) 853-4707

Compact, reliable pulsed power for high power microwave (HPM) generation is of particular interest to the Air Force. These generators require either high peak power at relative low duty cycle and high field strengths, or high average power at high duty cycle and lower field strengths. Development of each specific HPM generator has its own unique challenges. However, all have in common problems associated with the exposure of various devices materials to extreme electromagnetic, thermal and mechanical environments. This topic focuses on studying and utilizing new materials - dielectrics, insulators, metals and interface coatings in the design of components of the compact pulsed power systems such as modulators, capacitors, switches and anodes for cold cathode sources. Fundamental studies on compact pulsed power generation and innovative material and engineering techniques are needed to reduce the size and mass of these pulsed power components. An effective research effort in any of these component systems will require a combination of theory, experiment and modeling.

An example of a research area that is within the scope of this topic is high energy density pulsed power capacitors. The energy density of pulsed power systems for high power microwave (HPM) systems remains limited by the storage capabilities of the dielectric sub-system, which may consist of either capacitors or solid dielectric lines. Gigawatt-class HPM systems generally operate from megavolts to hundreds of kilovolts with pulse durations no more than several hundred nanoseconds long. The state-of-the-art for commercially available pulsed power capacitors approaches 2 J/cc. However, in practice, repetition rate (as high as 100 pps), discharge rate <0.1 microseconds and lifetime requirements for HPM systems limit the energy density of these capacitors to less than 0.5 J/cc. However, advances in pulsed power switches, capacitors and cold cathode anode materials are necessary to develop compact, reliable electric power on directed energy systems as well as advanced air and space platforms. All these areas are within the scope of this topic.

SF.10.02.B3915: High Power Microwave Source Research

Hendricks, K.J - (505) 853-3915

Vacuum electronic sources over a wide range of wavelengths at high power density represent a current area of research interest for the Air Force Research Laboratory. These sources span the range from 1GHz L-band sources at gigawatts of power to 90GHz W-band sources at megawatts of power to THz sources at hundreds of watts of power. Each of these technology areas shares the extreme difficulties of coping with large power densities that stress current materials technology as well as the physical understanding of basic physics phenomenology of the sources operation. As such, this research area requires a strong coupling between experimental work, theory, and modeling and simulation.

This research area consists of the following foci of interest: 1) Novel vacuum electronic sources, operating in the range from 1 GHz to the THz regime; 2) New technologies, such as nonlinear transmission lines, that provide wide ranges of frequency tunability and agility; 3) Supporting technologies to enable these devices. This area comprises technologies such as new cold cathode materials, new electron collectors, new vacuum window technologies, new vacuum pumping technologies, and new pulsed power materials and topologies; 4) Adoption of advanced materials modeling to investigate new materials for all aspects of these sources. Efforts to improve each of these areas, with strong coupling between theory, experiment, and modeling, comprise a vital aspect of these research goals.

AFRL-Directed Energy

Schmitt-Sody, Andreas
Assistant Chief Scientist
3550 Aberdeen Ave SE, Bldg. 497
Kirtland AFB, New Mexico 87117
Telephone: 505-846-3950
Email: andreas.schmitt-sody.1@us.af.mil