Robust and deterministic source of photon number states on demand

Quantum Sensors are used in a wide variety of applications including microscopy, positioning systems, communication technology, electric and magnetic field sensors, as well as geophysical areas. Significant gains from Quantum Sensors include technologies important for a range of NASA missions including efficient photon detection, optical clocks, gravimetry, gravitational wave sensing, ranging, and optical interferometry. Entangled multi-particle states used for precision measurements provide tools to reach the so-called Heisenberg limit and thus, overcome the shot-noise limit (fundamental noise limit for classical systems) and hence perform measurements at a precision unachievable for classical sensors. Quantum photon-number states, also known as Fock states, are the key ingredient to realizing the most useful entangled multi-particle states. Furthermore, photon-number states have applications in quantum communication and quantum information sciences as well. Physical Sciences Inc. (PSI) and the University of Illinois Urbana-Champaign (UIUC) will develop a robust and deterministic source of photon-number states. The source is based on spontaneous parametric down-conversion inside a low-loss optical loop a switchable quantum buffer and will produce quantum photon-number states on demand at the telecommunications wavelength, thus providing a key resource for advanced quantum sensors. Quantum sensors create transformative opportunities to utilize intricate quantum mechanical phenomena in novel ways to perform ultrasensitive measurements. In particular, measurements using highly entangled photon states can overcome the standard shot-noise limit and greatly improve the precision of interferometric measurements, reaching the so-called Heisenberg limit. Multiphoton number states, also known as Fock states, can be used to create such quantum states. However, despite an abundance of theoretical proposals, experimental demonstrations of photon number states are rare & their creation suffers from low probability-of-success techniques that makes them unsuitable for practical precision measurements. We propose a deterministic source of photon number states based on spontaneous parametric down-conversion (SPDC) in an optical loop formed by a ring cavity. Our approach relies on a seeded SPDC process with heralding to achieve an iterative photon-addition protocol to build up the required photon-number state. An optical cavity establishes a loop architecture around a SPDC source. Within Phase II, we will develop the photon-number source based on an SPDC source placed within a low-loss optical loop. Our design will leverage the key designs and subsystems developed in Phase I program and further develop the photon-number source by: Design and build a fast switchable optical loop having high transparency > 99.5%, with a SPDC crystal integrated. Reducing the electronic latency to 1 round-trip by increasing the length of the optical loop by implementing a longer delay line using a Herriott cell. Design and build an SPDC source with a heralding efficiency above 96%. Develop a high fidelity (90%) photon-number resolving detection setup for up to 5 photons. Develop a diagnostic tool capable of characterizing photon number states up to 5 photons, and capable of quantifying the fidelity of the number state and indistinguishability of the generated photons. Assembling, alignment and characterization of next generation (N=5) photon-number source able to create a 5-photon number state with probability above 30% and repetition rate of ~200 kHz This effort will result in the development of an on-demand source of photon number states. In addition to quarterly progress reports, all relevant designs and data will be delivered to NASA.

Exotic quantum states – including squeezed states, entangled states, and photon-number states – have a range of applications for multiple NASA missions and programmatic needs. For example, photon-number states are directly relevant for characterizing energy-resolving single-photon detectors, and as a resource to create optimal states for optical metrology, such as N00N states. Controllable production of fixed photon numbers in multiple spatial modes is also an assumed resource for advanced optical quantum processing, e.g., boson sampling. As highlighted by the National Quantum Initiative (NQI), quantum technologies are critical to our national security and competitiveness. Photon-number states and their derivatives are key elements for improving the precision of optical metrology, e.g., light-wave interferometry, which in turn has myriad applications in device and materials characterization, studying biological systems, etc.

This is early/mid-stage (TRL 4) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.