AF04-001 TITLE: Robust Single-Frequency Solid-State Seed Laser with Random Access of Wavelength
TECHNOLOGY AREAS: Sensors, Electronics, Battlespace, Weapons
OBJECTIVE: Develop and demonstrate single-frequency, wavelength-agile, CW solid-state laser with controllable frequency.
DESCRIPTION: Active laser tracking of a remote, fast moving and maneuvering target or cluster of targets for space surveillance and control operations requires a wavelength-tunable, narrow linewidth laser with unique capability to meet the following requirements:
1. Output power no less than 100 milliwatts (mW) at or around 1.06 microns (um).
2. Monolithic construction to reduce components and alignment constraints.
3. Lightweight and compact.
4. Controllable frequency tunability over a range of 1/cm (one inverse-centimeter,
or a frequency range of 30 GHz) in the vicinity of 1.06 um, with random access to
lasing frequency.
5. Set-on accuracy of the output lasing frequency of 100 megahertz (MHz).
6. Lasing frequency tuning/switching time of less than 100 milliseconds (ms).
Conventional methods for laser wavelength tuning based on intra-cavity spectral selectors or an alteration of the optical length of the micro-cavity cannot provide the performance level as needed. Achieving fast-tunability over the specified frequency range will require novel concepts and designs. This solicitation seeks innovative research and generation of creative concepts and original designs leading to the development, demonstration, and evaluation of a laser system that can serve as a frequency-tunable seed laser for space/air surveillance and control. Modeling/simulation and analysis are encouraged to guide in the course of identifying novel solutions enabling the realization of a rapidly tunable solid-state laser source.
PHASE I: Develop a preliminary design for a tunable solid-state laser that meets the technical requirements for space surveillance and control. Demonstrate its feasibility and assess its practical applicability in a laboratory environment. Characterize the proposed laser system and establish its operation and performance envelope. The proposed system design must be realizable within the scope of a Phase II SBIR contract. Risk reduction tasks that support the design may be carried out. The Phase I products are the laser system design, the final report, and a Phase II proposal (if requested).
PHASE II: Further refine the Phase I preliminary design to fabricate, integrate and assemble a prototype laser system based on the final plan. Measurements to assess system performance such as tuning speed and range, output power as a function of lasing frequency, output frequency stability, linewidth, and beam quality (M-squared) should be carried out against realistic application scenario drivers. The products should include the laser system with any power supplies and chillers, test and demonstration drivers, measurement data of system performance, a plan for a full-scale space tracking application and demonstration, and the final report.
DUAL USE COMMERCIALIZATION: There are numerous applications that require or could benefit from the use of scalable, frequency-stable, fast-tunable laser sources. Potential military applications include remote sensing, active laser tracking of fast-moving targets including missiles, satellites, and cross-communication systems in military environments. One or more potential commercial applications of this technology include laser communications with wavelength division multiplexing, laser profilometry, vibrometry, high-density optical data storage, as well as range-finding applications and laser clocks.
REFERENCES: 1. W. Koechner, Solid-State Laser Engineering, Fourth Edition (New York: Springer-Verlag, 1996).
2. F. Duarte, Tunable lasers handbook, San Diego: Academic Press, 1995.
3. J. Zhang, H. Ma, R. Wang, F. Li, C. Xie, K. Peng, All-solid-state single frequency ring Nd:YVOsub 4 tunable lasers, Zhongguo Jiguang/Chinese Journal of Lasers; July 2002, vol. 29, no. 7 pp. 577-579.
4. S. Kuck, Laser-related spectroscopy of ion-doped crystals for tunable solid-state lasers, Applied Physics B: Lasers and Optics, 2001, vol. 72, no. 5, pp. 515-562.
5. L. Zhang, J. Dai, W. Zhang, X. Lu, Y. Wang, J. Zhao, L. Chai, Q. Wang, P. Deng, W. Chen, All-solid-state tunable Yb:YAG laser, Zhongguo Jiguang/Chinese Journal of lasers, October 2001, vol. 28, no. 10, pp. 873-876.
KEYWORDS: Rapidly Tunable Laser, Narrow Linewidth, Wide Tuning Range, Stable Frequency, High Power, Wavelength-Agile Tunable Laser
AF04-002 TITLE: Laser System for Space Control and Protection
TECHNOLOGY AREAS: Sensors, Electronics, Battlespace, Space Platforms, Weapons
OBJECTIVE: Develop phase-conjugate based laser systems for neutralizing surveillance and optical communication modules in space, air and ground targets.
DESCRIPTION: Space control and protection missions may be implemented by delivering a laser beam with sufficient energy onto a distant target. This is to suppress (or optically jam) space, air, or ground-based surveillance or optical communication modules placed on various platforms pointing toward the laser transmitter. The application demands a laser system that has maximal throughput efficiency and minimal losses. To be effective, such a laser system should compensate not only for a beam jitter caused by turbulent atmosphere, and rapid changes in the relative position between the transmitter and target, but also for decrease in the laser beam divergence and the spot size on the target.
It is widely accepted that adaptive optic systems are not capable of compensating for dynamic variations at rates higher than 1 kHz. An alternative solution for this problem is to use a laser system with optical phase conjugation (OPC) methods. It is essential that the system is self-steering to the target and does not require a high accuracy pointing mechanism for lightweight and low cost. It is a well-established fact that delivery of the laser energy onto the target can be achieved when this target serves as an output coupler of the resonator. This also satisfies the conditions of minimal losses for oscillation. The objective of this project is to develop and demonstrate a laser system with phase conjugate mirror (PCM) for delivery of laser energy to a distant target to jam or degrade the performance of optical sensor or transmission subsystem on board the target pointing toward the laser transmitter.
PHASE I: Develop a preliminary system design of a PCM-based laser energy delivering system with an extended cavity filled with a turbulent medium for long distance targeting. Assess its feasibility for practical application to space control and protection mission. Identify, analyze and estimate the key parameters that can determine and limit such a system’s operations and performance. Evaluate the dynamic characteristics of the PCM laser capable to sustain the oscillation at realistic rates of change of turbulence, of switch between targets, and of the relative position between the transmitter and the target. Define an experimental plan and technology roadmap to demonstrate the operability and transferability of the system for space control and protection application.
PHASE II: Further refine the Phase I preliminary design to fabricate, integrate, and assemble a prototype of the laser system. Experiment and validate its operation and performance in a turbulent atmospheric environment and demonstrate the energy transfer onto multiple distance targets with high beam quality and optical jamming capability. Design an application and transition plan for a full-scale demonstration.
DUAL USE COMMERCIALIZATION: Many military and commercial systems require a high-energy transfer onto a remote object. In military sector such lasers can be used as a component of laser weapon module, when used to suppress ground-based or space-based surveillance systems, or as a component of the anti-missile defense system. In the commercial sector such a laser can find applications for a long-range (satellite, air space) laser tracking and communication.
REFERENCES: 1. L. Weinstein, Open resonators and open waveguides, Boulder, Colo., Golem Press, 1969.
2. Zel’dovich B., Pilipetskiy N., Shkunov V., Principles of Phase Conjugation, Springer -Verlag, Berlin, 1985.
3. A. Yariv, Quantum electronics, John Wiley & Sons, 1989.
4. H. Brussellbach, et. al. "Real-time atmospheric compensation by stimulated Brilloin-scattering phase conjugation" JOSA B, Volume 12, Number 8, August 1995 pages 1434-1447.
KEYWORDS: Space Control and Protection, Phase Conjugation, Optical Jamming, Performance Degradation, Laser Cavity, Phase Conjugate Mirror.
AF04-003 TITLE: High Gain Panoramic Optical Power Amplifier
TECHNOLOGY AREAS: Sensors, Electronics, Battlespace
OBJECTIVE: Develop and demonstrate high gain, high efficiency, wide viewing angle optical power amplifier.
DESCRIPTION: Laser tracking and pointing of the remote targets for space/air surveillance and control applications require the development of compact, high electrical plug in efficiency, and high gain optical amplifiers. The desired operating characteristics include a sufficiently wide (panoramic) angle of view (better than 54 mrad), high output power (>17 dB), and high electrical plug in efficiency (>40%) in order to provide high quality amplification of an image. Several critical issues have to be solved in order to build the desired amplifiers, such as maximal suppression of the super luminescence and possibility of spurious oscillation. Both effects can result in a decrease of the level of inversion population in the gain medium and therefore decrease the gain coefficient. High level pumping of a gain medium creates thermal distortions in its volume, resulting in aberrations of the laser beam. Thus, the proposed design concepts should account for all these and related problems and minimize their effect on the quality of the output laser beam.
PHASE I: Develop candidate preliminary designs of "panoramic" optical power amplifier (POPA) for active tracking and pointing of multiple targets in space and air. Explore different laser material, fiber configuration, pump mechanisms and coupling techniques, and low loss pump laser filters to arrive at several promising design concepts. Identify, analyze and estimate the key parameters that can determine and limit POPA's operation and performance envelope. Assess feasibility and effectiveness of each candidate design for practical use in laser tracking and pointing systems. Define an experimental plan to demonstrate its operability and applicability for active laser tracking in space/air surveillance and control applications.
PHASE II: Fabricate and test several POPA devices based on the materials and design concepts developed in Phase I. Test the devices to determine output and efficiency over a range of operating conditions likely to be required for laser tracking and communications. Verify noise figure and bandwidth capability that can meet requirements for active laser tracking and pointing in real operating environment.
DUAL USE COMMERCIALIZATION: The developed amplifiers can be used for military space/air surveillance systems. They should find many dual use applications in image projection systems, medical and biomedical instrumentation, laser communication, etc. POPAs could also be used for fiber network communications, reducing thermal control requirements, increasing distance between repeaters, and permitting more bandwidth per fiber in wavelength division multiple access schemes.
REFERENCES: 1. V. Dominic, et al., “110W Fibre Laser”, Electronic Letters, 35, 14, (1999).
2. S. Hofer, et. al., “Single-frequency master-oscillator fiber power amplifier system emitting 20 W of power,” Optics Letters, Vol. 26, No. 17, (2001) 1326-1328.
KEYWORDS: Laser Tracking and Pointing, Optical Power Amplifier, Wide-Angle of View, High Gain, High Efficient
AF04-004 TITLE: UV/X-Ray Bio-Decontamination
TECHNOLOGY AREAS: Chemical/Bio Defense, Sensors, Electronics
OBJECTIVE: Develop a compact source of ultra-violet and x-ray radiation to use for decontaminating aircraft, vehicles, and buildings subjected to a biological warfare attack.
DESCRIPTION: High intensity UV optical sources and x-ray sources are needed for decontamination of assets subjected to biological threats. Currently, most techniques to neutralize biological agents rely on either bulky equipment or gases and other materials corrosive or harmful to many objects. The combination of an x-ray and UV source in a relatively small package, has the potential for decontamination on the surface and sub-surface of assets. However, at the present time, UV sources have insufficient fluence and efficiency for this application and at best are difficult to combine with an x-ray source. At the present, new generations of nanoparticulate phosphors are being investigated as sources of electrically pumped UV radiation. The aim is to develop a UV and x-ray source, (electron beam driven) that utilizes new advances in nanoparticulate powders as UV phosphors. At the end of Phase I the potential phosphors will be specified and a design developed to combine the UV source and x-ray source in a single compact, electron-beam-driven device.
PHASE I: Develop a design for combined UV and x-ray source. The design shall include specifics of x-ray production as well as UV production. The design shall be sufficient enough to allow fabrication of a proto-type system in Phase II. Potential phosphors will be specified and a design developed to combine the UV source and x-ray source in a single compact, electron-beam-driven device.
PHASE II: The prototype article shall be fabricated and demonstrated during this phase. A prototype source will be delivered to AFRL/DE at the end of Phase II.
DUAL USE COMMERCIALIZATION: The source can be used for purification of equipment used in bio-technology areas as well as medical areas. These applications include cleaning of equipment that has been exposed to bio-materials that can be affected by UV and z-ray radiation. Viruses and other pathogens in the medical arena also constitute another area of interest.
REFERENCES: 1. "Continuous-wave ultraviolet laser action in strongly scattering Nd-doped alumina", B. Li, et al, p. 394, OPTICS LETTERS , Vol. 27, No. 6 , March 15, 2002.
2. "Laser action in strongly scattering rare-earth-metal-doped dielectric nanophosphors" G. R. Williams, S. B. Bayram, S. C. Rand T. Hinklin and R. M. Laine, PHYSICAL REVIEW A 65 , 013807, 2001.
KEYWORDS: Electronic Devices, Environmental Effects, High Power Microwaves, Laser, Optics, and Power Systems, Nanotechnology
AF04-005 TITLE: Automated Techniques for Extracting Four Dimensional Space-Time Data from Ground-Based Imagery of Space Objects
TECHNOLOGY AREAS: Information Systems, Electronics, Space Platforms
OBJECTIVE: Develop automated techniques that extract four-dimensional space-time data from a sequence of ground-based imagery taken of a space object.
DESCRIPTION: The Air Force Research Laboratory’s Directed Energy Directorate (AFRL/DE) owns many of the world’s finest ground-based space sensors including those operated at the Starfire Optical Range (DES) and as a part of the Maui Space Surveillance System (DEBI). Further, DE’s Surveillance Technologies Branch (DEBS) conducts state of the art research to ensure the quality of imagery collected at these sites will continue to improve for years to come. The Satellite Assessment Center (SatAC, DEBE) is interested in innovative techniques for automating the analysis of this imagery. SatAC currently has processes in place to glean four dimensional space-time data from these images, but they require a great deal of human interaction and are very slow (on the order of months to complete). The output of these processes is a 3D model of the space object as well as parameters describing the object’s position and orientation as a function of time. The goal of this SBIR is to develop and demonstrate algorithms/techniques that will produce this 4D information in near-real time (<20 minutes). The fidelity of the model will necessarily be a function of the image resolution and all discernible image artifacts should be modeled. The orientation of the space object should be determined for all image capture times and predictions of future and past motion should be calculated as well. The model reconstruction problem is mostly solved for cases where the imaged object is cooperative, but our objects of interest are not necessarily cooperative. Images can only be taken at certain times – governed by the laws of orbital mechanics -- and we usually have no control over the behavior of the space object at those times. These limitations make this problem much more complex and worthy of further research.
PHASE I: Investigate a number of algorithmic approaches to the problem. Required Phase I deliverables will include a prototype system that proves the concept and helps determine expectations for Phase II. Proof of the concept would entail successful 4D modeling from at least one real image sequence of a space object or a simulated sequence based on realistic imaging conditions.
PHASE II: Based on the findings from Phase I, develop, demonstrate and validate a more robust prototype system that incorporates a combination of the most promising approaches from Phase I. Exact expectations will be formulated during Phase I, but the Phase II prototype will be robust enough to handle real data under less than ideal conditions, and produce richer, more accurate representations of shape and motion as well as accommodate articulating components on the subject.
DUAL USE COMMERCIALIZATION: Many government agencies as well as private businesses are very interested in the field of automatic object recognition of uncooperative subjects. The most natural extension of this research would be to apply the same techniques to help the military paint a clearer picture of the air, ground and sea battlefields as well. Additionally, automated terrorist identification from surveillance video is another application that would directly benefit US intelligence agencies in the war against terrorism. Scene reconstruction for autonomous robot navigation during planetary exploration is yet another application that would support the country’s space program. Similarly, automobile manufacturers could utilize this technology to equip their cars with sophisticated collision avoidance systems. Lastly, any industry that relies on robotic assembly lines could utilize this technology to automatically sort and separate items from an unorganized pile of parts.
REFERENCES: 1. A. Adan, C. Cerrada, and V. Feliu, “Automatic pose determination of 3D shapes based on modeling wave sets: a new data structure for object modeling.” Image and Vision Computing. 1 Oct 2001: 19(12):867-890.
2. Alessando Chinso, Paolo Favaro, Hailin Jin, and Stefano Soatto, “Structure From Motion Causally Integrated Over Time.” IEEE Transactions on Pattern Analysis and Machine Intelligence, April 2002.
3. K. Kutulakos and S. Seitz, “A Theory of Space Carving.” International Journal of Computer Vision, 38(3):199-218.
4. R. Y. Li, “3-D image processing for object recognition.” 6th International Conference on Fuzzy Theory and Technology, 23-28 Oct, 1998. Research Triangle Park, NC, USA.
5. D. Morris and T. Kanade, “A Unified Factorization Algorithm for Points, Line Segments and Planes with Uncertainty Models,” Proceedings of the International Conference on Computer Vision, Narosa Publishing House, pg 696-702, 1998.
6. Conrad J. Poelman and Takeo Kanade, “A Paraperspective Factorization Method for Shape and Motion Recovery.” IEEE Transactions on Pattern Analysis and Machine Intelligence, 19(3):206-218, 1997.
7. “Proceedings 1997 Image Understanding Workshop.” 11-14 May 1997. May Hyatt Regency, New Orleans, LA. Vol I and Vol II.
8. P Zhilkin and ME Alexander, “3D image registration using a fast noniterative algorithm.” Magnetic Resonance Imaging, 18(9):1143-1150, Nov 2000.
KEYWORDS: Space Situational Awareness, Space Superiority, Image Processing, Automatic Target Recognition
AF04-006 TITLE: Conformal Impulse Receive Antenna Arrays
TECHNOLOGY AREAS: Sensors, Electronics, Battlespace
OBJECTIVE: Develop co-planar conformal impulse receive antenna arrays that can be integrated into airborne platforms such as Unmanned Aerial Vehicles (UAVs) and aircraft.
DESCRIPTION: This effort will develop and demonstrate design concepts for electromagnetic impulse receive antenna arrays that are co-planar (minimum depth) capable of being conformably mounted on the body or wing of airborne platforms. It is expected that to achieve the co-planar and conformal requirements that the antenna design(s) will be a multi-element array approach. The received impulse signals will contain frequencies of interest from approximately 200 MHz to 2.0 GHz. The goal for the frequency response over this range is +/- 5 dB. To capture the lower frequencies, the antenna aperture must be large thereby requiring that the individual elements of the array be electrically bonded to form the larger aperture. The antenna gain should be as high as feasible. Additionally, antennas that can be fabricated of flexible conductive materials that can be bonded to inflatable structures are highly desirable. The output from each element of the array should be capable of being interconnected so as to allow a single analog output or individually connected to waveform digitizers.
PHASE I: Requires innovative research and concepts that can be modeled and feasibility demonstrated experimentally with a small scale antenna design. The modeling and experimental data should not only demonstrate the impulse response of the antenna design(s), but also show the potential to meet the mechanical and structural requirements for integration into airborne platforms.
PHASE II: Requires the development and demonstration of a full size antenna array(s) including full electromagnetic characterization and physical properties mounted on a mockup of a typical airborne platform structural element such as a fuselage or wing.
DUAL USE COMMERCIALIZATION: Military uses of this technology when combined with other elements of an impulse radar system include airborne identification of obscured and uncooperative targets. Civilian applications include land mine identification and mapping of underground utility lines and hazardous waste sites.
REFERENCES: 1. Carl E. Baum, “Transient Arrays”, pages 129-138, Ultra-Wideband, Short-Pulse Electromagnetics 3, Plenum Press, New York, 1997, ISBN 0-306-45593-5.
2. Errol K. English, “Tapered Periodic Surfaces, A Basic Building Block for Broadband Antenna Design”, pages 227-235, Ultra-Wideband Short-Pulse Electromagnetics 2, Plenum Press, New York, 1995, ISBN 0-306-45002-X.
3. Atanu Mohanty and Nirod K. Das, “Low Cross-Polar, Short-Pulse Radiation Characteristics of Printed Antennas Covered by a Polarization Grating”, pages 195-202, Ultra-Wideband Short-Pulse Electromagnetics, Plenum Press, New York, 1993, ISBN 0-306-44530-1.
4. T. S. Angell, R. E. Kleinman, and B. Vainberg, “Asymptotic Approximations for Optimal Conformal Antennas”, pages 177-183, Ultra-Wideband, Short-Pulse Electromagnetics 3, Plenum Press, New York, 1997, ISBN 0-306-45593-5.
5. C. Jerald Buchenauer, J. Scott Tyo, and Jon S. H. Schoenberg, “Aperture Efficiencies of Impulse Radiating Antennas”, pages 91-108, Ultra-Wideband, Short-Pulse Electromagnetics 4, Plenum Press, New York, 1999, ISBN 0-306-46206-0.
KEYWORDS: Impulse Signals, Short-Pulse, Ultra-Wideband, Array Antennas, Receivers, Conformal, Co-planar, Airborne
AF04-007 TITLE: Optical Fibers for High-Power, Mid-Infrared Laser Diodes Emitting in the 2.0 Micron to 5.0 Micron Wavelength Range
TECHNOLOGY AREAS: Materials/Processes, Sensors, Weapons
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