Inside Homerun’s UC Davis R&D: From Sand to Fused Silica

In Parts 1 and 2, we explained why AI’s “Copper Wall” is driving interest in photonics and why ultra‑high‑purity fused silica glass is such an important enabling material.

Part 3 goes inside the lab. Here, we walk through what Homerun and the University of California, Davis (UC Davis) are actually doing with Santa Maria Eterna (SME) silica sand, from femtosecond laser purification to one‑step Fast Joule Heating (FJH) fused silica glass and why having Professor Subhash H. Risbud lead this work matters.

Why UC Davis – and Why Lasers?

Homerun’s silica strategy begins with geology: high‑purity, low‑iron silica sand from our SME project in Bahia, Brazil. Independent testing by Dorfner Anzaplan confirmed that this material is suitable feedstock for fused silica using conventional multi‑step processing routes.

The question we posed next was: Can we go further?

• Can we use advanced processing, in particular lasers and fast electric heating to purify silica to ultra‑high levels without hazardous chemicals?
• Can we convert sand directly into fused silica glass in fewer steps, using electric power instead of complex chemical flowsheets?

To explore this, Homerun partnered with the Risbud Research Group at UC Davis, a team with decades of experience at the intersection of glass, lasers and photonics.

Professor Subhash H. Risbud is widely recognized for early work on femtosecond‑laser modification of fused silica, including the fabrication of waveguides, splitters and Mach–Zehnder interferometers inside bulk glass at Photonics West 2002. That same understanding of how ultrafast lasers interact with silica is now being applied to purifying silica sand and making fused silica glass.

Step 1 – Femtosecond Laser Purification to Ultra‑Pure Silica

The first major milestone in the UC Davis collaboration was the development of a femtosecond thermal laser processing method to purify raw silica sand to ultra‑high purity.

Key points:

• In 2024, Homerun announced that UC Davis researchers, working with raw silica from Homerun’s Belmonte/SME region, had achieved +99.99% SiO₂ purity (+4N) using a single‑step femtosecond laser thermal process.
• The process uses intense, tightly controlled femtosecond laser pulses to induce subtle structural and optical changes at the surface of each grain, driving off or transforming impurities without the use of chemical reagents or energy‑intensive mechanical processing.
• Professor Risbud described these as “very exciting results,” noting that this was the first time a single‑step laser process had converted raw impure sand to 99.999% silica in as little as two hours.

Building on this, Homerun later sent >99.99% SiO₂ silica, previously purified by the U.S. Department of Energy’s NREL using traditional calcination and leaching, to UC Davis to test whether femtosecond laser processing can push purity even higher.

On top of the technical work, Homerun and UC Davis have filed a patent application titled “Process for obtaining high‑purity silica sand and the resulting product.” It describes a femtosecond laser ablation‑based process that raises silica purity from 99.75% to above 99.99% by significantly reducing impurities such as titanium, calcium, magnesium and iron, without hazardous chemicals.

For investors, the significance is twofold:

• It demonstrates a credible, IP‑backed path to ultra‑pure silica using advanced, reagent‑free processing.
• It shows that our silica is not just high‑quality in the ground, it responds well to high‑end purification technologies.

Step 2 – Fast Joule Heating: From Sand to Fused Silica Glass in One Step

The second major R&D milestone is turning that purified silica into fused silica glass using a one‑step thermoelectric Fast Joule Heating (FJH) process.

In March 2026, Homerun announced that UC Davis had successfully produced fused silica glass directly from raw SME silica sand using the FJH method.

How it works (simplified):

• Silica powder from SME is loaded into a “tube‑within‑tube” configuration.
• The inner tube holds the silica; the outer tube contains a conductive medium such as graphite.
• A high‑voltage pulse is discharged through the conductive medium, rapidly heating it via Joule heating (electrical resistance heating).
• Temperatures in the system reach around 2,000 °C, above the 1,710 °C melting point of silica, and the sand transitions to fused silica glass in seconds.

Professor Risbud notes that the tube‑within‑tube design is critical, because it allows current to flow in the conductive layer while keeping the silica physically separate, sustaining high temperatures long enough to form fused silica glass.

For Homerun, there are several potential advantages if this approach scales:

• No chemical reagents – the process uses only electric power and a conductive medium, generating no chemical waste stream.
• Speed – melting and glass formation occur very quickly once target temperature is reached.
• Flexibility – the FJH method can potentially be adapted to different atmospheres and configurations using commercially available equipment.

The next step in the plan is to move from bench‑scale experiments to larger‑scale tests using off‑the‑shelf equipment, to evaluate how reproducible and scalable FJH is for fused silica glass production.

As with the laser purification, these results are still at the R&D and scale‑up stage and have not yet been independently verified. There is no guarantee that FJH will become a commercial process, but it is an important proof‑of‑concept that raw SME sand can be taken all the way to fused silica glass in a single thermoelectric step.

Why Risbud’s Photonics Background Matters

The R&D is not happening in isolation; it builds directly on decades of work in silica photonics.

Back in 2002, Risbud co‑authored “Waveguide Fabrication in Fused Silica Using Tightly Focused Femtosecond Laser Pulses,” presented at Photonics West. That work:

• Demonstrated that tightly focused femtosecond pulses can induce controlled refractive‑index changes (on the order of ) inside bulk fused silica.
• Used those index changes to write waveguides, splitters and Mach–Zehnder interferometers directly inside glass.
• Linked these optical changes to underlying structural modifications, including densification and the formation of specific defect centers in the glass network.

In other words, the same lab that was among the first to write 3D photonic structures inside fused silica using femtosecond lasers is now applying that knowledge to purifying silica sand and making fused silica glass.

For Homerun shareholders, this matters for credibility:

It shows that our R&D partnership is anchored in a world‑class photonics and glass science group, not a generalist lab. It increases the likelihood that process development is grounded in a deep understanding of how lasers and high‑temperature processing affect silica at the microstructural level.

Where We Are Today – and What’s Next

Taken together, the UC Davis program has established three important proofs‑of‑concept for Homerun:

1. Our silica responds well to advanced purification – Femtosecond laser processing and other methods have taken raw and pre‑purified silica to ultra‑high purity (up to 99.999% SiO₂) without hazardous chemicals.
2. Our silica can be converted directly into fused silica glass using FJH – UC Davis has produced fused silica glass from SME sand using a one‑step, thermoelectric process at ~2,000 °C.
3. We have begun to protect this work with IP – Homerun and UC Davis have filed a patent application on the femtosecond‑based silica purification process, and additional IP opportunities may emerge as FJH scale‑up continues.

There are still significant steps ahead:

• Scaling FJH to larger batch sizes and continuous configurations.
• Further characterizing the optical and mechanical properties of the fused silica glass produced.
• Exploring pathways to integrate these processes into existing fused silica and photonics supply chains.
• Continuing independent and third‑party assessment where appropriate.

Looking Ahead to Part 4

Part 3 has focused on how Homerun and UC Davis are turning SME silica into ultra‑pure silica and fused silica glass and why we believe this work is grounded in world‑class photonics expertise.

In Part 4 – From R&D to Opportunity: What Fused Silica Could Mean for Homerun Shareholders, we will:

• Map where fused silica sits in the value chain from sand to photonics and semiconductors.
• Outline potential strategic paths if our technologies scale.
• Highlight the key milestones we believe investors should watch over the coming years. Our goal remains the same: to help Homerun shareholders understand both the scale of the opportunity and the real work and risk involved in getting there.