DARPA is offering $25 million in grants for its new Information in a Photon (InPho) program to maximize the use of photons. The Information in a Photon Broad Agency Announcement seeks proposals addressing the basic science and the associated unifying physical and mathematical principles that govern the information capacity of optical photons, exploiting all relevant physical degrees of freedom.
The photon, the indivisible unit of electromagnetic energy, is a fundamental carrier of information. Numerous degrees of freedom are available for the conveyance of information on a photon including frequency, phase, arrival time, polarization, orbital angular momentum, linear momentum, superposition states, correlation, entanglement, etc.
DARPA Information in a Photon Goals
Because optical photons (l = 0.5mm) are approximately 106 times more costly (i.e., energetic) than their RF (f = 1GHz) counterparts, optical photons represent a critical resource within a wide variety of military applications ranging from fiber and free-space optical communications systems to various visible (VIS) and infrared (IR) sensing platforms. Motivated by both the high cost and application-centrality of optical photons we seek to extract maximum benefit from this valuable resource.
The primary goal of the Information in a Photon (InPho) program is to pursue the basic science and the associated unifying physical and mathematical principles that govern the information capacity of optical photons, exploiting all relevant physical degrees of freedom. Important outcomes of the InPho program will include (a) the rigorous quantification of photon information content for communications and imaging applications in both the classical and quantum domains, (b) novel methodologies to maximize the scene information that can be extracted from received photons in next-generation imaging/sensing platforms, and (c) novel methodologies to maximize the information content of transmitted/received photons in next-generation communication systems. Additional applications expected to benefit from a deeper understanding of photon information content include, but are not limited to, chemical/biological sensors, laser designators, navigation systems, photogrammetric applications and/or various forms of spectroscopy.
Program Description
The goal of the Information in a Photon (InPho) program is to pursue the fundamental physics governing the information content of optical photons. The success of this program will result in our ability to quantify the fundamental information content of a photon and exploit this information capacity for imaging/sensing and communications applications of importance to DoD.
The InPho program will consist of three thrust areas: Scientific Foundations, Imaging, and Communications. The objective of the Scientific Foundations Thrust will be to rigorously quantify photon information content for communications and imaging applications in both the classical and quantum domains. The result of this thrust will be to establish the basic scientific principles and associated mathematical formalisms that will facilitate efficient pursuit of the remaining two thrust areas.
Basic research in the Imaging Thrust will be directed toward extracting maximum scene information from minimum photon count. Conventional wisdom suggests that an image requires more than 1000 photons per pixel in order to be useful. This traditional rule-of-thumb, when combined with a desire for ever-increasing pixel-counts, can result in large apertures and/or long integration times which in turn increase both complexity (e.g., the need for stabilization) and/or size, weight and power (SWaP) costs (e.g., large glass mass).
It is apparent that current imaging systems under-utilize photon information capacity. Consider a natural scene that is imaged using an 8 bit per pixel focal plane. With a requirement to collect 1000 photons per pixel we see that such a system achieves a photon efficiency of 125 photons per bit or 8e-3 bits per photon (bpp). Because of the redundancy that is characteristic of natural imagery, it is not uncommon for such a scene to be visually indistinguishable after compression by 10x, suggesting an even lower photon information efficiency of 8e-4 bpp. Drastically increasing this photon efficiency will provide revolutionary capabilities for DoD VIS/IR imaging platforms.
Basic research in the Communications Thrust will be directed toward maximizing the information content of every transmitted/received photon in a free-space optical (FSO) communication system. Recent progress on the information capacity of optical communications has largely focused on novel spectrally dense modulation techniques for increasing the spectral information efficiency of these channels. Recent demonstrations approaching 10 bits/sec/Hz in fiber suggest that similar techniques may also be successfully employed for FSO applications. Unfortunately, these spectrally efficient solutions are generally photon inefficient, often achieving < 1e-3 bpp.
Conversely, photon-efficient modulation such as pulse position modulation (PPM) has been used to demonstrate 2 bpp with only a modest spectral efficiency of 0.25 bits/sec/Hz. The Shannon limit for FSO channels that employ multiple photon degrees of freedom can be several orders of magnitude higher than any of these recent hero experiments. Approaching the Shannon limit therefore will drastically increase photon efficiency and will provide revolutionary capabilities for optical communications systems within a wide array of DoD applications. It is expected that such efficiency gains will also positively impact fiber-based communications systems.
DARPA is soliciting innovative research proposals focusing on maximizing the information content of optical photons within the context of imaging and communication applications. All proposed research must fully address the Scientific Foundation thrust and its corresponding end-of-program goal. In addition to describing research within the Scientific Foundation Thrust, all proposals must also choose one of the four technical areas of interest outlined below (i.e. classical imaging, quantum imaging, classical communications, or quantum communications) and only address the corresponding end-of program goals listed in Table 1. Although proposals received under this BAA will focus on a single Technical Area, we anticipate that individual researchers may participate in multiple teams when their expertise is clearly relevant to more than one.
Proposed research should investigate innovative approaches that enable revolutionary advances in science, devices, or systems aimed at maximizing the information capacity of optical photons. Specifically excluded is research that primarily results in evolutionary improvements to the existing state of practice.
Collaborative efforts/teaming are strongly encouraged. It is anticipated that this program will require an unprecedented multi-disciplinary team that brings together expertise from traditionally disparate disciplines including information sciences and optical physics, in addition to domain expertise such as communications and imaging.
DARPA seeks innovative proposals in the following four Technical Areas of Interests:
Imaging Thrust:
Technical Area One: Classical Imaging
New insights from the Classical Imaging community suggest that photon efficiencies approaching 1 bpp may be achievable. For example, it has recently been shown that compressive imaging techniques may be used to measure in a non-redundant (i.e., non-pixel) basis and thus may offer the potential for substantially increased photon efficiency. Computational imaging systems that provide improved image fidelity as compared with a conventional camera further support the notion of improved photon efficiency.
Extensions of this work to include information-theoretic analysis of compressive imaging provide additional evidence that photon efficiency can be drastically improved for task-specific measurement. Activities of interest within the Classical Imaging Technical Area therefore include, but are not limited to (a) imaging in extremely low-light environments, (b) compressive imaging, (c) novel image coding and priors, (d) information content of imagery, (e) image information carried by novel degrees of freedom, (f) 3D image information, (g) resource-constrained bounds on performance, etc.
The end-of-program goal for the Classical Imaging technical area is to demonstrate VIS/IR imaging reconstruction† with average photon efficiencies ≥ 1 bpp OR task-specific performance‡ ≥ 5 bpp. (See Table 1 for †, ‡ references)
Technical Area Two: Quantum Imaging
Recent demonstrations of novel Quantum Imaging techniques provide additional evidence for drastically increasing the information efficiency of individual photons. For example, ghost imaging experiments employing entangled photons enable the conveyance of image information within the correlation among multiple particles. The information capacity of these methods is currently unknown; however, multi-dimensional entanglement and/or incorporation of the compressive measurement paradigm are expected to enhance performance as well as photon information efficiency. Other quantum imaging systems are also of interest.
Single photon target detection/classification has been recently demonstrated and represents a task-specific measurement apparatus in which >1 bpp has been achieved. Activities of interest within the Quantum Imaging Technical Area therefore include, but are not limited to (a) novel entanglement for ghost imaging, (b) compressive ghost imaging, (c) single photon and entangled photon sources, (d) photon counting detector arrays, (e) single photon task-specific implementations, (f) quantum photonic memories, etc.
The end-of-program goal for the Quantum Imaging technical area is to demonstrate VIS/IR imaging reconstruction† with average photon efficiencies ≥ 1 bpp OR task-specific performance‡ ≥ 5 bpp. (See Table 1 for †, ‡ references)
Communications Thrust:
Technical Area Three: Classical Communications
New insights from the Classical Communication community also suggest that very high photon efficiencies may be achievable. For example, hybrid modulation formats such as PPM, quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), and dense wavelength division multiplexing (DWDM) employing multiple photon degrees of freedom may be used to simultaneously increase both photon efficiency and spectral efficiency. Recent studies of orbital angular momentum (OAM) represent a case in point. This novel degree of freedom has been analyzed for both modulation and for multiplexing.
Predicted FSO capacity enhancements of 10x appear to be realistic even in the presence of moderate atmospheric turbulence. Activities of interest within the Classical Communication Technical Area therefore include, but are not limited to (a) Shannon limits of FSO channels incorporating multiple optical degrees of freedom, (b) encoding and decoding methods/limits for novel degrees of freedom such as OAM, (c) physical limits to information capacity of turbulent channels, (d) extensions to fiber channels, etc.
The end-of-program goal for the Classical Communications technical area is to demonstrate optical communication that simultaneously provides photon efficiencies of 10 bpp and spectral efficiencies of 5 bits/sec/Hz.
Technical Area Four: Quantum Communications
Research in novel Quantum Communication techniques provide further evidence for drastically increasing the information efficiency of individual photons while simultaneously providing quantum mechanical guarantees on security. For example, recent progress on multi-photon and/or multi-dimensional (e.g., OAM) entanglement has recently demonstrated increased secure data rates arising from the increased dimensionality of the underlying Hilbert space.
These high-dimensional systems have also been proposed to offer increased noise tolerance. For example, hybrid entanglement on continuous variables (e.g., energy/time or position/linear momentum) has been used to simultaneously demonstrate a large secure alphabet (e.g., 4 bits per photon) without sacrificing the fundamental security of the entangled channel. Activities of interest within the Quantum Communication Technical Area therefore include, but are not limited to (a) multi-photon and multi-dimensional entanglement, (b) hybrid entanglement on multiple photon degrees of freedom, (c) information optimization in the trade space defined by capacity and security, (d) entanglement preservation for turbulent propagation, (e) high-efficiency quantum state sorters, etc.
The end-of-program goal for the Quantum Communication technical area is to demonstrate optical communication that simultaneously provides photon efficiencies of 10 bpp and secure data rates of > 1 Gbps.
This program requires the formation of unprecedented multi-disciplinary teams that bring together expertise from traditionally disparate disciplines including information sciences and optical physics, in addition to domain expertise such as communications and imaging. The program is conceived in three phases of no more than 12 months each (base period, option 1, option 2), with the thrusts, technical areas, and end-of-program goals given in Table 1.
Broad Agency Announcement
Information in a Photon
Defense Sciences Office
DARPA-BAA-10-19
Type: Other (Draft RFPs/RFIs, Responses to Questions, etc..)Posted Date: December 16, 2009
Model Broad Agency Announcement (BAA)
DARPA-BAA-10-19.doc (354.00 Kb)
Description: DARPA-BAA-10-1
Model Broad Agency Announcement (BAA)
Appendix A and B.pdf (461.90 Kb)
Description: DARPA-BAA-10-19 Appendix A and B
Contracting Office Address:
3701 North Fairfax Drive
Arlington, Virginia 22203-1714
Primary Point of Contact:
Dr. Mark Neifeld
mark.neifeld@darpa.mil
Model Broad Agency Announcement (BAA)
Points of Contact
The Technical POC for this effort is Dr. Mark A. Neifeld.
E-mail: DARPA-BAA-10-19@darpa.mil
The BAA Administrator for this effort can be reached at:
Electronic mail: DARPA-BAA-10-19@darpa.mi
DARPA/DSO
ATTN: DARPA-BAA-10-19
3701 North Fairfax Drive
Arlington, VA 22203-1714
Email: DARPA-BAA-10-19@darpa.mil
