SirenOpt sells $19.4M in equity toward a $32.4M offering

Why it matters

SirenOpt's filing shows the capital required to turn university research into factory equipment. Its $32.4M target is almost five times the size of either previously announced venture round.

Jared O'Leary, co-founder and CEO of SirenOpt, has signed a Form D reporting that the UC Berkeley spin-out sold $19.4 million of a planned $32.4 million equity offering, giving the company a substantially larger pool of capital to push its cold-plasma measurement system from the lab onto factory lines.

The Form D filed on September 18th identifies SirenOpt Inc. as the issuer and reports a total amount sold of $19,428,895. The headline figure needs unpacking: $7.4 million of the amount sold came from converted securities. That leaves about $12 million in sold securities outside the conversion, although the filing does not specify how much arrived as new cash. Another $13 million remains available in the open offering.

The filing identifies O'Leary as SirenOpt's chief executive and a director. It does not name the investors, a lead backer, the valuation, the share price or the terms of the converted securities.

O'Leary built SirenOpt around technology developed during his chemical engineering doctorate at UC Berkeley, where he studied learning-based methods for characterizing and controlling advanced-materials manufacturing. He previously earned a chemical engineering degree from Stanford and worked as an engineer and team lead at Theranos. SirenOpt's academic roots also run through co-founders Ali Mesbah, a UC Berkeley chemical and biomolecular engineering professor, and Joel Paulson, a University of Wisconsin-Madison professor whose research covers scientific machine learning and process control. UC Berkeley lists O'Leary and Mesbah as the underlying technology's inventors.

A much larger financing target

SirenOpt's $32.4 million offering target is almost five times the size of either of its two previously announced venture rounds.

In a July 2024 announcement, SirenOpt said it closed a $6.6 million seed led by Voyager Ventures and Visionaries Tomorrow, with Access Industries, Berkeley SkyDeck Fund, Climate Capital, Climate Club, Union Labs, Wireframe Ventures, Impact Science Ventures and Courtyard Ventures participating.

SirenOpt followed that in October 2025 with a $6.5 million strategic financing led by Hitachi Ventures. Jaguar Land Rover's InMotion Ventures, Voyager Ventures and Visionaries Tomorrow also joined. That round was intended to expand engineering, product and commercial hiring ahead of factory deployments planned for 2026.

The new Form D names Voyager partner Matthew Blain and independent director Philip Harper. It also identifies Tom Chi as a SirenOpt director. Chi, a founding member of Google X who worked on projects including Google Glass, founded climate and deep-tech investor At One Ventures in 2020. The filing does not identify At One Ventures as an investor, so Chi's board appointment cannot be treated as confirmation that his fund joined the offering.

Chi's addition still matters for O'Leary. SirenOpt is entering the expensive stage of building an industrial hardware business: converting promising measurements into repeatable equipment that can survive production speeds, customer qualification and factory integration. Chi brings product-development experience and an investment practice focused on commercializing capital-intensive technologies.

Measuring what production lines miss

SirenOpt's PlasmaSens platform sends cold atmospheric plasma across a material's surface and analyzes the resulting signal with physics-informed machine learning. SirenOpt says the system can infer properties including thickness, density, porosity, resistivity, conductivity and chemical composition without destroying a sample or stopping the production line.

The approach comes from the overlap among O'Leary's work on manufacturing control, Mesbah's research in plasma processing and predictive control, and Paulson's work in scientific machine learning. SirenOpt describes the models as grounded in physical behavior, giving manufacturers an interpretable measurement rather than a prediction generated solely from images or historical production data.

O'Leary is targeting production processes where small variations can turn expensive materials into scrap. SirenOpt lists applications across battery electrodes, semiconductor wafers and thin films, advanced packaging, aerospace components, electronics and power systems. Its semiconductor materials work spans silicon, gallium nitride, tungsten, titanium, nickel and dielectric films, among other materials.

Manufacturers already have established inspection options. Thermo Fisher sells inline systems for measurements including electrode thickness and coating weight, while AMETEK Surface Vision focuses on visual defects in battery electrode webs. SirenOpt's pitch is that one plasma-based platform can extract several material properties that would otherwise require separate measurements or destructive laboratory tests. Independent production data establishing PlasmaSens' accuracy, throughput and economics at factory scale has not been published.

That factory transition already has public funding behind it. In October 2025, the California Energy Commission approved a $2.4 million grant for SirenOpt to develop inline inspection and real-time process control for battery electrode manufacturing. The state described the project as moving SirenOpt's existing offline inspection platform toward a pilot-scale inline demonstration, with work scheduled through March 2030.

The new offering arrives during the year SirenOpt had planned to start putting instruments into factories. Completing the full $32.4 million target would give O'Leary considerably more room to hire applications engineers, manufacture systems and absorb the long qualification cycles that accompany production equipment. The SEC filing gives no specific allocation for the proceeds.

More capital extends SirenOpt's runway for that deployment work. Production results will decide whether PlasmaSens becomes standard factory infrastructure across multiple materials markets or remains a specialized characterization instrument. SirenOpt has raised enough toward the new offering to begin answering that question on actual manufacturing lines.