Opportunities in Austin, United States

Exowatt is revolutionizing the energy landscape for the AI era with our groundbreaking P3 system that captures solar energy, stores it as heat, and generates electricity on demand. Founded in 2023 and backed by leading investors including Andreessen Horowitz, Sam Altman, and Felicis, we're committed to providing clean, modular, and scalable power that meets the rapidly growing demands of AI infrastructure. Our mission is to make sustainable renewable energy always available and almost free, enabling technological advancement while protecting our planet. We are seeking a highly skilled and motivated Lead Optical Engineer to own concentrator design, optical testing, and model validation for the P3. In this role, you will design and optimize non-imaging optics for maximum flux transfer, build and automate optical test setups, validate models against on-sun performance, and work across the optic-to-thermal boundary that defines the P3 architecture. You will collaborate closely with the Optical Product Development, R&D, and thermal teams to ensure alignment between design intent, test outcomes, and delivered system performance. Non-imaging concentrating optics experience is required for this role. This position is based in Austin, TX preferred, however an alternate location of Miami, FL is possible for the right candidate. If hired for this role, relocation to one of these sites is required. We provide relocation assistance.

Design and optimize non-imaging concentrating optics — Fresnel primaries and secondary optical elements — to maximize flux transfer, uniformity, and intercept factor rather than image quality.

Build an optical error budget that rolls slope error, tracking error, and alignment tolerances into an intercept-factor model, and validate it against hardware.

Design for uniform irradiance on the receiver, mitigating hot spots and the material stress that uneven flux drives on a thermal absorber.

Design, automate, and optimize optical test setups for our concentrators and complex opto-mechanical assemblies, ensuring efficiency and precision.

Characterize concentration ratio, acceptance angle, focal-spot flux distribution, and end-to-end optical efficiency, and validate these against Monte Carlo ray-tracing models.

Automate ray-tracing, test procedures, and analysis using Python (and C++/MATLAB as needed) to streamline workflows and improve accuracy.

Conduct on-sun testing — flux mapping, calorimetry, and pyrheliometer-based efficiency measurement — and reconcile field results with simulation.

Feed validated optical performance into annual optical-efficiency models, thermal models, and the system digital twin (developed with NVIDIA and AWS).

Characterize soiling, UV degradation, and abrasion on polymer optics, and evaluate anti-reflective and anti-soiling coatings to support a 30-year field lifespan.

Define and validate manufacturing tolerances for optical components produced at high volume in domestic factory settings.

Collaborate with optical, mechanical, electrical, thermal, and systems engineering teams to ensure alignment across product development stages.

Maintain clear, organized technical documentation for internal teams and external stakeholders.

Education & foundation

Master's or PhD in Optical Engineering, Physics, Electrical Engineering, or a related discipline, with a minimum of 3 years of industry experience, or equivalent work experience.

Hands-on experience with optical systems in a lab environment, including assembly, alignment, integration, and testing.

Core non-imaging design competencies

Concentrator design experience with Fresnel lenses (ideally molded PMMA or silicone-on-glass), compound parabolic concentrators (CPCs), parabolic troughs, heliostats, or secondary optical elements (SOEs). Designing a coupled primary + secondary stage for CPV or CSP is an ideal match.

Fluency in the language of concentration limits — étendue conservation, geometric concentration ratio, acceptance angle, and the concentration-acceptance product (CAP).

Command of the edge-ray principle and tailored-optics design, optimizing for flux transfer over image quality; familiarity with Winston/Miñano/Benítez methods or simultaneous multiple surface (SMS) design is a strong plus.

Experience designing for irradiance uniformity, hot-spot mitigation, and intercept-factor optimization on a receiver or absorber.

Software & simulation

Proficiency with Monte Carlo ray-tracing tools built for illumination/flux work — TracePro, LightTools, FRED, Photopia, or CSP-specific codes such as SolTrace or Tonatiuh. Zemax/OpticStudio in non-sequential mode counts; sequential-only imaging experience is a weaker fit.

Ability to build custom ray-tracing or optimization routines in Python or MATLAB, and to construct optical error budgets (slope, tracking, and alignment tolerances rolled into an intercept-factor model).

Solar-specific domain knowledge

Familiarity with sun-shape and DNI modeling, circumsolar ratio, cosine losses, and annual optical-efficiency simulation (often paired with SAM or similar performance models).

Tracking-system tolerance analysis — how pointing error degrades concentration — with awareness of UL 3703-adjacent tracker considerations.

Understanding of soiling, UV degradation, and abrasion on polymer optics, and of anti-reflective and anti-soiling coatings.

Hardware & manufacturing

Exposure to injection or compression molding of PMMA/silicone Fresnel optics, diamond turning of mold masters, and metrology for large-aperture optics (deflectometry, photogrammetry, VSHOT-type slope measurement).

Receiver/absorber interface experience — cavity receivers, selective absorber coatings, or thermal receiver flux limits — demonstrating work across the optic-to-thermal boundary that defines the P3.

Outdoor test experience: on-sun testing, flux gauges and calorimetry, and pyrheliometer-based efficiency measurement.

Ways of working

A problem-solving mindset, with the ability to work independently and collaboratively.

Excellent communication skills, capable of articulating technical concepts to both technical and non-technical audiences.