Synthetic Alkali Atom Vapor Density for Atom-Based Sensors - SBIR Topic DON26BZ01-NV037

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This topic was temporarily posted by the Department of War SBIR Program on March 2nd 2026 and removed the following day.
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Funding Amount:

Est. $240,000

Deadline to Apply:

Est. April 29th, 2026.

Objective:

Simplify the thermal management of practical atom-based quantum sensors based on alkali atoms by creating a passive atom source operated at thermal equilibrium based on a synthetic alkali vapor density for rubidium or cesium atoms.

Description:

Quantum sensors based on atoms offer the opportunity to produce measurements with excellent sensitivity or long-term stability, making them attractive use in atomic clocks, magnetometers, or inertial sensors. In these sensors, the atomic vapor represents the sensing media where variations in signal magnitude from fluctuations in atom number can lead to instability or loss of sensitivity. Maintaining consistent signal throughout environmental conditions represents one of several key design criteria for atom-based sensors for use outside the laboratory.

Many atom-based sensors rely on heavy alkali atoms, specifically rubidium and cesium. This is because of the simplified, hydrogen-like energy level structure, the availability of narrow-linewidth semiconductor diode lasers on the relevant D1 (795/895 nm) and D2 (780/852 nm) transitions, the accessibility of commercial microwave electronics at the 3-10 GHz hyperfine splittings, and the ease of production of vapor phase atoms at modest temperatures. The temperature dependence of the alkalis [Ref 1] leads to thermal stabilization at 80-130°C (ideal for vapor cells at 10e12-10e14/cc) or closer to room temperature (ideal for atom trapping at 10e8-10e10/cc). These temperatures rarely align with thermal profiles of other aspects of the system, requiring additional design at the expense of size, weight, and power (SWaP).

Active approaches to alkali regulation have been demonstrated to manipulate the vapor to a non-equilibrium state. These approaches involve forced chemical reactions, intercalated graphite, alkali impregnated materials glasses [Refs 2,3]. In each case, a feedback loop must respond to measurements of the vapor density, leading to extra sensor complexity.

An equilibrium vapor density represents the simplest atom source which can be synthetically adjusted to an elevated temperature through a mixture [Ref 4]. Here, a primary species mixed with a secondary species reduces the equilibrium vapor density of both species by the mixing ratio following Raoult’s Law [Ref 5]. Selecting a lower vapor density secondary species limits the negative impact of additional atom-atom collisions. Such an approach can be applied to laser-cooled systems in addition to vapor cells to enable equilibrium operation at elevated system temperature, providing tight thermal regulation at low power.

Who will win?

If you can achieve the objective above better than any other company on the market, you have a very high-likelihood of success and should apply.

Who is eligible to apply?

Any company that meets the following criteria:

• For-profit company

• U.S.-owned and controlled.

• 500 or fewer employees (including affiliates)

How Can BW&CO Help?

1) End-to-end support including, strategy, writing of the full proposal, and administrative & compliance support.

2) Proposal strategy and review.

3) Administrative & compliance support.

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