The National Institute of Standards and Technology (NIST) is seeking sources capable of providing a narrow-linewidth, Cs D1 transition laser, with the intention of potentially issuing a Sole Source Award to OEwaves if no other suitable vendors are identified. The laser must meet stringent specifications, including an output wavelength centered at 894.59 nm, a spectral linewidth of 10 Hz or less, and various performance metrics related to frequency noise, intensity noise, and tuning capabilities, essential for the Fundamental Thermodynamics Group's research needs. Interested parties are encouraged to respond with their capabilities and relevant information by contacting Elizabeth Timberlake or Tracy Retterer via email, with a deadline for questions set for January 21, 2025. This notice serves as a sources sought notice and does not constitute a commitment to issue a solicitation or award a contract.