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OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Quantum Science (including Encryption & Computing); Directed Energy; Biomedical OBJECTIVE: To demonstrate a scalable, low noise laser for barium ion qubits. DESCRIPTION: Barium ion qubits are the new preferred choice for ion based quantum computing and potentially atomic clocks because they offer the conveniences of ion trapping for control and robustness, but don’t require (near) ultraviolet lasers that are very difficult to make. The tradeoff is that the most important laser, the “clock” laser is now at 1762 nm, which is outside the spectral region where low noise lasers, high power lasers have been commercialized. Recently, there have been several demonstrations indicating a possible way forward [1,2]. In this project, an integrated approach to develop a laser with 100 mW output with less than -140 dB/Hz random intensity noise (RIN), and less than 100 Hz linewidth is required using a technique that is scalable in power, potentially using multiple channels, and manufacturable. The laser system must also have the needed control mechanisms for frequency tuning to the atomic line. PHASE I: To qualify for Direct to Phase 2, the proposer must have a system design and device operation model ready for immediate fabrication, preferably using commercially accessible fabrication facilities. This typically excludes University research-focused cleanroom facilities unless those facilities are part of some larger institute that facilitates commercial access (e.g. a Microelectronics Commons Hub). The system design and model should include detailed analysis of the frequency and amplitude noise expected, the control system required, and a system concept for how this laser will fit into a barium ion laser control system that includer other wavelengths. PHASE II: Build and demonstrate the barium ion clock laser system with 100 Hz linewidth, 100 mW output power, -140 dB/Hz RIN that can lock to Ba+. A surrogate frequency reference is acceptable if the performer doesn’t have a Ba+ spectroscopy capability. Phase II Base amount must not exceed $2,095,000 for a 27-month period of performance. PHASE III DUAL USE APPLICATIONS: This device is expected to commercially viable for quantum computing and atomic clock programs funded in the public and private sectors, but also could be commercialized for medical and high energy laser applications because of the wavelengths lower impact on human tissue. REFERENCES: Ahmadi, Morteza et al. “Scalable narrow linewidth high power lasers for barium ion optical qubits.” Opt. Express, 32, 10, (2024) Fedotov, Andrei et al. “High-power 1762 single frequency fiber laser system for trapped barium ion qubits.” Proceedings or SPIE, Quantum West (2025) KEYWORDS: Quantum, laser, photonics, thulium, barium ion, atomic clock, quantum computer