#quantumlightsources

NIST invests $3.19 million in small business innovation for quantum, AI, and biotechnology.

SBIR program news today

Eight small businesses received about £2.5 million from NIST to foster high-tech prototyping. SBIR's AI, medical diagnostics, and quantum technology initiative focuses on critical industries. These Phase II grants allow entrepreneurs to prototype their concepts in two years. Scalable quantum light sources, cybersecurity assessment tools, and new imaging technologies are supported. The Commerce Department funds this study to ensure commercial viability. They increase energy efficiency, public health, and national security through private innovation.

The competitively selected projects aspire to commercialize and receive non-SBIR Phase III financing by developing Phase I concepts into functioning prototypes.

Standardizing biopharmaceuticals and medical imaging

Biotechnology and healthcare, which require regularity and accuracy, receive most financing. Madison, Wisconsin-based Calimetrix LLC received $399,998 to improve medical imaging accuracy. The company is generating human-like imaging "phantoms" to simulate fatty liver tissue. These phantoms allow researchers and physicians to standardize MRI and CT scan comparisons across vendor platforms, ensuring consistent patient data regardless of scan site.

Quincy, Massachusetts-based Applied Imaging Solutions LLC will receive $400,000 to modernize biopharmaceutical cell culture monitoring in medication manufacture. Current cell culture upkeep requires intensive manual observation. Applied Imaging Solutions is developing an AI-powered system for contactless cell viability and metabolite level measurement using SWIR-HSI. It improves bioreactor control to make life-saving medications safer and more efficient.

Nano-Simulation and Quantum Interconnect Improvements

Boulder-based Icarus Quantum Inc. received a grant from NIST, demonstrating its commitment to quantum technologies. With $400,000, the company built a semiconductor quantum dot photon source. This scalable system integrates numerous high-efficiency photon sources on a chip. It is designed as a “plug-and-play” approach to let researchers integrate quantum interconnects into their systems, advancing quantum computing and networking.

Software from Schenectady, New York-based AMAG Consulting LLC supports these hardware advances. AMAG is enhancing its SimuSEM program, which models electron beam interactions with scanning electron microscope materials, with a $400,000 funding. Surface roughness, magnetic interactions, and charging effects are modeled in Phase II. These enhancements will allow scientists to take more exact nanoscale photographs, reducing the need for costly physical testing.

Monitoring the Environment and Cybersecurity

SBIR also addresses digital safety and the environment. Philadelphia-based MyExposome Inc. will receive $395,814.74 to improve wearable environmental sensors. The company uses silicone wristbands to detect PFAS exposure, sometimes known as "forever chemicals." MyExposome is developing solvent-free extraction technologies to identify more PFAS and make environmental research and health assessments more cheap.

San Diego-based ObjectSecurity LLC raised $399,908.58 online to develop the Operational Technology Artificial Intelligence – NIST Compliance Tool (OTAI-NCT). This cybersecurity tool evaluates software and hardware manufacturer policies using reputable sources like the National Vulnerability Database. The final “cyber-hygiene score” helps buyers make informed purchases and protects public safety and national security.

Optical Imaging Resolution and Energy Efficiency

General imaging resolution and infrastructure projects complete Phase II awardees. Harpers Ferry, West Virginia-based Universal Schedule and Booking LLC received $400,000 to build an intelligent digital home energy management system. Their method estimates household energy usage without expensive hardware sensors, overcoming a major barrier to energy-saving technology adoption.

HighRI Optics Inc. in Oakland, California, received $399,858.96 for developing a binary pseudo-random array (BPRA) for optical image enhancement. With this invention, scientific, manufacturing, and military imaging equipment will have improved resolution.

Looking Ahead

The eight initiatives demonstrate the US innovation economy's diversity. NIST helps small businesses complete the 24-month Phase II R&D cycle to create power grid resilience and cancer detection technology. As they accomplish milestones, these firms will aim for Phase III, where they can market their discoveries.

Which program is SBIR?

Quantum Astronomy

A basic physics constraint that blindfolds even the most powerful telescopes has slowed the search for an additional Earth by decades. A unique combination of astrophysics and quantum mechanics allows us to observe the secret worlds orbiting distant suns through their brilliant brilliance. Researchers believe a new era in space exploration is coming as they progress beyond “classical” imaging and into quantum-enhanced sensing.

Rayleigh Limit and ‘Firefly’ Problem

One must first understand the vast difference between a star and its planets to grasp the assignment. Astronomers liken direct exoplanet photography to photographing a firefly kilometers away and inches from a gigantic stadium searchlight.

A physical law that has limited telescope resolution for almost a century, the Rayleigh criteria, is the difficulty. The wavelength of light and the telescope's aperture size define the minimum resolution needed to distinguish two objects, according to this law. A single, hazy point is generated when star and planet light are too close from the viewpoint. Since stars are billions of times brighter than their planets, this fuzz almost always completely obscures the planet's existence.

Modern “classical” solutions use coronagraphs, physical masks that filter out starlight, but they have drawbacks. Smaller, Earth-like planets in the “habitable zone” are hard to determine, but they can identify massive gas giants far from their parent stars. This “inner working angle” is the last frontier in exoplanet hunting, and quantum technology can help.

Quantum Leap: Spatial Mode Demultiplexing

Macquarie University and the University of Maryland suggest a fundamental change in light perception. Light is seen as a stream of information-carrying quantum states rather than a wave to be recorded on a flat sensor in the revolutionary method.

Spatial mode demultiplexing does more than collect all photons. Instead, a quantum-sensitive device sorts photons into “spatial modes” or patterns. This is possible because planet and star light excite different quantum modes since they reach the telescope at slightly different angles.

Examining these modes using quantum techniques lets astronomers accurately “filter” photons. This method lets researchers escape the Rayleigh limit in lab simulations and resolve quantum light sources five orders of magnitude closer than classical physics allows.

Quantum computers' role in processing the impossible

These quantum sensors' “interference patterns” and high-dimensional data would overwhelm even the most powerful conventional supercomputers. This is where quantum computers' processing power matters.

“Quantum state estimation” is a quantum computer strength. From noisy telescope data, it can use simulations to determine which star and planet configuration caused that signal. These gadgets use "quantum hypothesis testing" to distinguish a star-planet system from a single star, even when the planet's signal is practically undetectable.

The Biosignatures Search

The “holy grail” of this technological marriage is large-scale direct imaging. Only 1.2% of exoplanets have been directly photographed. Most are discovered indirectly, such the "transit method," which involves observing if a star dims as a planet passes in front of it.

Direct imaging is preferable since it allows spectroscopy of light filtered through a planet's atmosphere. This light can be dissected for biosignatures including water, oxygen, and methane. Chemical clues indicate life could exist.

Future in the Stars

Initial implementation of these systems is ongoing. NASA's Future Habitable Worlds Observatory may use “quantum-optimized” coronagraphs to lower the observing angle. “Earth 2.0”—a planet similar in size and temperature to ours but shrouded by its sun—may finally be visible.

Hardware matches theory. Stanford University researchers have developed nanoscale optical devices to manipulate photon "spin" at ambient temperature, bringing quantum imagers closer to portability.

Discover how Type-II parametric down conversion obtains high-quality entangled photons from lossy systems for next-generation quantum networks.

Quantum Communication Building Blocks

Quantum technology, which is evolving rapidly, requires subatomic light creation and control. Entangled two-mode Gaussian states, the “building blocks” of sophisticated communication protocols and continuous variable quantum computing, are central to this project. Researchers at Paderborn University under Denis A. Kopylov, Torsten Meier, and Polina R. Sharapova presented a significant study in APL Quantum disclosing a more effective approach of collecting these important quantum resources from realistic, “lossy” situations.

Down Parametric Conversion

The team focused on type-II parametric down-conversion (PDC). A nonlinear optical technique produces “signal” and “idler” fields of entangled photons from a high-energy pump pulse and a waveguide. Photon pairs are more than simple particles because their complex, multimodal light structure allows high-speed quantum information processing.

Real-World Hardware Challenges

Real-world quantum hardware faces several hurdles, even though theoretical models assume optimal conditions. The Paderborn researchers found that multimode complexity and intrinsic waveguide losses limit modern quantum light sources.

Intrinsic losses from waveguide construction faults cause dispersion and “mixed” quantum states. The waveguide's dispersion and the laser pump's profile form a multimode structure that disperses light across many frequencies. To exploit this light, scientists must determine specific “mode shapes” for measurement. Choosing the wrong mode can eliminate non-classical properties, “washing out” the quantum advantage.

Squeezing Connection: A New Entanglement Measure Identifying the relationship between squeezing and entanglement in these systems is a major theoretical contribution of the study. Quantum “squeezing” occurs when noise in one variable (like momentum) increases while noise in another (like location) decreases below the vacuum level.

The researchers found that two-mode bipartite states (TMBS) recovered from type-II PDC have bipartite entanglement proportional to squeezing. Experimentalists need this reduction. By detecting the most entangled and “squeezed” light, they can find an optimisation target.

New Standard: The team developed the Maximally Squeezed (MSq) assumption to determine which modes to measure. This new approach was compared to two industry standards, the Williamson-Euler (WE) basis and the Mercer-Wolf (MW) basis, which are used because to their high photon counts.

The scientists used rigorous numerical simulations of waveguides with balanced and unbalanced losses to prove the MSq-basis's entanglement extraction advantage. In “unbalanced” losses, signal and idler modes attenuate differently, revealing the differences. Their simulations showed that the MSq-basis preserved entanglement, although the standard Mercer-Wolf basis may lose it.

Debunking the ‘More is Better’ Myth

Experimentalists may be most surprised by the researchers' "corollary" that maximising intensity does not maximise entanglement. Standard labs make it easy to adjust equipment for maximum photons. The study showed that the MSq-basis, which uses less photons but maintains higher “purity” and correlation, often yields less entanglement than the Mercer-Wolf basis, which uses the most photons.

The authors noted that “the intuitive experimental approach of maximising intensity would not result in a maximally entangled TMBS,” suggesting that labs may need to calibrate their quantum sources differently.

Quantum Protocol Futures

Research has far-reaching effects outside the lab. This work provides a “blueprint” for building complex quantum light in realistic, lossy installations, making these systems suitable for Quantum Key Distribution (QKD) and scalable quantum computing.

The authors noted that the MSq-basis may be easily adjusted to account for transmission and detection losses, making it a flexible tool for future quantum networks. This discovery, financed by the “Photonic Quantum Computing” (PhoQC) project, moves us closer to a time when quantum communication will be practical and dependable.

Future Technology Opportunities via Shaping Quantum Light Engineering

Manipulating photon structure in space and time creates customised quantum states for next-generation communication, sensing, and imaging. Researchers from Wits University's School of Physics have demonstrated the ability to manipulate quantum light in time and space to create high-dimensional and multidimensional states in collaboration with the Universitat Autònoma de Barcelona. This landmark work shows how structured photon light with purposely chosen spectral, spatial, or temporal features can enable high-capacity quantum communication and advanced quantum technologies.

Quantum Light Engineering Evolution

Recently, quantum light engineering—designing quantum light for a specific purpose—has advanced and is finally showing its full potential. Professor Andrew Forbes of Wits, the study's corresponding author, says the profession has changed significantly in 20 years. Professor Forbes says the toolkit for quantum state customisation was “virtually empty” 20 years ago. Scientists now have compact, effective on-chip quantum structured light generators to produce and manipulate these quantum states.

Modern approaches including multiplane light conversion, nonlinear optics, and on-chip integrated photonics are bringing structured quantum states closer to real-world applications in quantum networks, sensing, and imaging.

High-Dimensional Encoding and Noise Resistance

Organising photons allows access to high-dimensional encoding alphabets. This characteristic increases noise resistance and encodes more information per photon. Thus, quantum structured light is a suitable platform for secure quantum communication.

Quantum light engineering modifies photon energy, time, and space to create these specialised states. High-precision sensing and ultra-secure quantum communication require this technology. Recent breakthroughs in this subject focus on sophisticated entanglement, integrated sources, and new materials to overcome efficiency hurdles and provide bright, controllable quantum light for practical applications.

Innovative Methods and Platforms

The review paper discusses rapid development in ultrafast temporal structuring, nonlinear quantum detection, and multidimensional entanglement. Higher-dimensional quantum light processing and generation on-chip sources are being developed.

Important approaches and resources for this development include:

Miniaturising quantum light sources like microring resonators onto silicon chips to create compact, integrated devices is called “on-chip photonics.” Construction of useful devices requires these mechanics.

Nonlinear Optics: Strong lasers and unique materials like silicon membranes and quantum dots create nonclassical light states.

Quantum dots and emitters: Scientists are developing very effective single-photon sources and photonic devices to control light precisely.

Quantum Materials: Silicon and diamond are being modified to manage light interaction and emission for scalable devices.

Challenges and Prospects

Despite great advances, the sector nevertheless has significant issues. Spatially organised photons still negatively affect some real-world channels, the authors note. This restricts long-distance transmission compared to polarisation. Professor Forbes says quantum or classical structured light has a “very low” distance reach. This problem is a “opportunity,” he says, “stimulating the search for more abstract degrees of freedom to exploit.”

An intriguing new method is adding topological properties to quantum states, which make them resilient to perturbations. The finding that quantum wave functions can be topological promises the preservation of quantum information even if the entanglement is unstable.

The study changed quantum optics. Researchers say quantum structured light's future “looks very bright indeed,” but more work is needed to enhance dimensionality, photon counts, and quantum states that can sustain realistic optical circumstances.

Wide-ranging Technology and Security Impact

Quantum light engineering is used in many significant technologies. These include:

Entangled photons are needed for unhackable quantum key distribution (QKD) and high-capacity networks in quantum communication. Unbreakable quantum communication networks will change the future.

Structured photons enable precision metrology and the construction of sensors that can detect small signals like disease-related molecular vibrations. This allows molecular fingerprinting for early disease detection and high-resolution quantum imaging.

Quantum networks use numerous channels to carry more information.

Quantum computing involves building robust quantum processors with entangled photons, such as 6-photon entanglement, and quantum memories for complex operations.

Energy and Space: Better batteries and light-to-electricity conversion in energy and self-charging, radiation-resistant computing components in space are expected.

Quantum photonics innovation: Silicon Nitride-integrated tunable emitters yield 94.7%. Scalable, CMOS-Compatible Heterogeneous Integration of InGaAs Quantum Dots Enables Large-Scale Quantum Circuits.

Next-generation scalable quantum photonic technologies for secure communication and quantum computation require the capacity to effortlessly merge optimised components onto a device with minimum signal loss. Jasper De Witte, Atefeh Shadmani, Zhe Liu, and others demonstrated the scalable integration of mature indium gallium arsenide (InGaAs) quantum emitters into silicon nitride (SiN) photonic circuits to overcome this basic obstacle. This development paves the way for advanced single-photon technology.

Heterogeneous integration, especially micro-transfer printing, combines high-performance quantum light sources and the low-loss SiN platform. The primary innovation is this. This technique optimises the passive photonic circuit material and quantum light source separately to maximise device performance.

Heterogeneous Integration for High Yield and Scalability

Heterogeneous integration, or hybridisation, is the best method for high yield and scalability in complex quantum circuits. SiN photonic integrated circuits (PICs) and quantum emitters are built separately before joining.

InGaAs QDs

The technology uses micro-transfer printing to precisely insert pre-characterized emitters like InGaAs quantum dots embedded in GaAs waveguides on the SiN device. By precise positioning, many quantum components and different materials can be integrated. Importantly, the scientists used readily available micro-transfer printing methods to achieve 94.7% processing yield. Scaling up functioning devices per batch and getting from proof-of-concept prototypes to mass production requires this high yield.

Monolithic integration fabrication of emitters directly within SiN material has a high integration density, but it still struggles to place good-quality emitters deterministically across large areas, making hybrid approaches better for high-yield scalability.

Silicon Nitride Benefits Due to its many advantages, silicon nitride (SiN) is the ideal photonic platform for this integration. SiN is noted for its low optical losses, which provide signal integrity and light transmission across complex photonic circuits. Since it is compatible with CMOS microelectronics, SiN photonics can use traditional industrial fabrication standards.

Waveguides on a silicon wafer are created using typical lithographic methods to make the SiN platform. While molecular beam epitaxy creates quantum dots inside GaAs membranes, they are converted into small transfer coupons.

Compatible CMOS and Electrical Control

Spectral inhomogeneity and operational noise plague solid-state quantum emitters. Researchers solved the problem by inserting integrated InGaAs quantum dots in a vertical p-i-n heterostructure.

This p-i-n arrangement locks charge states, reduces noise, and allows practically blink-free operation. Electrical biassing allows active wavelength tunability, overcoming spectrum inhomogeneity in solid-state emitters. The electrical control is compatible with ordinary CMOS technology because the bias voltages are less than 0.6V. Experimental results reveal that the integrated emitters are reliable, pure, and flicker-free after transmission.

Protecting fragile parts

The transfer technique was technologically difficult due to the tiny and delicate GaAs nanobeams, which are 160 nanometres thick and 300 nanometres wide. The researchers wrapped each nanobeam in a larger rectangular photoresist coupon to provide mechanical strength during transfer and release.

Photoresist tethers on the GaAs substrate held these coupons during release. The device design has to be changed to accommodate objective magnification and positional alignment limits while using commercial micro-transfer printing techniques to retain high coupling efficiency from the GaAs nanobeam to the SiN waveguide.

Large-Scale Quantum System Outlook

This study displays large-scale quantum photonic circuit integration. Emitters with CMOS-compatible tunability and 94.7% processing yield enable high-throughput manufacture.

Better quantum light sources are possible with new developments. Vienna and Innsbruck Multi-Photon Emission Control improvements for quantum technologies.

Recent discoveries by Vienna and Innsbruck research teams have improved the quest for non-classical light, which is needed for quantum technologies like secure communication and quantum computing. Despite the goal of producing pure single photons, resonant excitation in atoms, whether natural or artificial, always emits multi-photons. To better handle these complex light-matter interactions and generate more reliable and effective quantum light sources, two complementary research efforts have yielded crucial insights and feasible solutions.

Artificial Atom Multi-Photon Dynamics Revealed

L. Jehle, L. Carosini, L. M. Hansen, J. C. Loredo, and P. Walther along with F. Giorgino and P. Zahálka at the University of Vienna have studied multi-photon processes in silicon quantum dots. Because of their strong optical properties and solid-state synthesis, silicon quantum dots are becoming more popular platforms for quantum light source creation.

In “Multi-photon emission from a resonantly pumped quantum dot,” upper-order auto-correlation functions (g(2), g(3), and g(4)) and high-resolution temporal measurements quantify these emissions, providing a nuanced understanding of light-matter interactions. They proved that a single excitation pulse can emit four photons.

Conclusions from their detailed analysis include:

With single-photon emission, two, three, or four photons can be detected from a single stimulation. By showing that a bunched source (g(2)(0) > 1) does not always have a better probability of emitting two photons than one, the work showed the importance of the vacuum probability (likely to produce no photons). Increased multi-photon contributions occur in even pulse areas (Θ = 2nπ) due to quantum dot re-excitation during the excitation pulse duration. Closely resolved temporal studies confirmed that these multi-photon events are caused by successive spontaneous emissions, meaning the photons do not share the same temporal mode. This study showed a time-gating approach to purify single-photon sources. By rejecting early-arriving photons and catching photons during a specified time frame after excitation, researchers can prevent multi-photon events while maintaining detection efficiency. This works better than lowering excitation power for purity.

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Enhancing Multi-Photon Generation with Passive Demultiplexing

Gregor Weihs and Vikas Remesh from the University of Innsbruck led a worldwide research team that developed a sophisticated approach to overcome the disadvantages of traditional multi-photon state creation. Researchers develop multi-photon states from a single quantum dot using fast electro-optic modulators (EOMs) to multiplex emission into spatial and temporal modes. EOMs require specialised engineering, are expensive, and reduce efficiency.

Using stimulated two-photon excitation (sTPE), the Innsbruck team produces photon streams in multiple polarisation states from a quantum dot without active switching elements. This method limits multi-photon rate by the quantum dot's intrinsic lifetime rather than an EOM's switching speed.

The procedure:

By carefully timing laser pulses to excite the quantum dot, a biexciton state is generated. After that, polarization-controlled stimulation pulses that deterministically emit photons in the horizontal (H) and vertical (V) polarisation states follow. When used with active demultiplexing technologies, passive demultiplexing is cost-effective and doubles multi-photon generation. With g(2)(0) values of 0.022(2) for V-polarized photons and 0.028(2) for H-polarized photons, the group produced high-quality two-photon states with excellent single-photon characteristics. They validated high indistinguishability with adjusted Hong-Ou-Mandel (HOM) visibilities of 90(1)% for V-polarized photons and 93.7(3)% for H-polarized photons.

This innovation enables safe multi-party communication and fits directly into quantum key distribution systems. It also shows potential for multi-photon interference studies, which test quantum mechanical ideas.