Senior Optical Engineer - Stray Light

Xcimer Energy

200

Denver, CO

Posted on: 2026-04-29

Category: energy

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Employment type:

Full time

Experience required:

Senior

Salary

Salary not provided

About the company:

Xcimer Energy is a fusion energy company focused on commercializing laser-driven inertial confinement fusion, which it describes as the only scientifically validated form of fusion energy. The company is developing high-energy excimer laser systems designed to ignite fusion reactions using fuel derived from seawater and lithium, with the goal of delivering safe, clean, and affordable electricity that is cost-competitive with fossil fuels and renewables. Its mission centers on decarbonizing energy-intensive sectors such as artificial intelligence infrastructure, desalination, and industrial processes that require firm, always-on, carbon-free power. Xcimer's technical approach relies on electron-beam-pumped excimer lasers combined with a pulse compression technique called Stimulated Brillouin Scattering (SBS), which compresses microsecond laser pulses to nanosecond durations without damaging optics. In 2024 the company broke ground on Phoenix, its first prototype high-energy laser system, located in Denver, Colorado, and announced the start of its operations in June 2026. Phoenix is the first electron-beam-pumped excimer laser built in the private sector in more than two decades and validates key elements of the company's low-cost laser fusion architecture. Xcimer's longer-term target is Athena, which it describes as the world's first laser fusion power plant, expected to deliver 400 megawatts of continuous clean energy by 2035. The company has received a U.S. Department of Energy approval of its fusion power plant preconceptual design and technology roadmap milestone, and collaborates with industrial partners such as TRUMPF Laser SE. With a team of nearly 200 engineers, physicists, and business professionals, Xcimer positions itself as the most technically mature private laser fusion company.

Xcimer Energy leverages decades of research on Inertial Fusion Energy (IFE) combined with groundbreaking new laser architecture. Our mission is to deploy fusion power plants to meet global decarbonization goals as fast as possible. Xcimer has assembled a team of leaders in tough tech, fusion science, and manufacturing with a track record of rapid execution. Supported by leading investors, Xcimer is uniquely positioned to deliver limitless, clean, fusion power to combat climate change. Join us in powering a better world with inertial fusion!

This is a full-time, onsite role based at our headquarters in Denver, CO.

As a Senior Stray Light Optical Engineer, you will be the primary technical authority on non-sequential ray tracing and stray light mitigation. Your work will focus on modeling and designing complex optical layouts to identify and mitigate ghosts, hot spots, fringing effects, and other parasitic light paths that could degrade system performance or cause optical damage.

In this highly collaborative role, you will work closely with sequential optical designers, opto-mechanical engineers, material scientists, and optical systems engineers. You will implement mechanical feature models (e.g., baffles, beam dumps) directly into non-sequential software to validate their effectiveness. You will also write custom scripts to automate complex analyses and process large datasets, ensuring our high-energy DUV systems operate safely and efficiently.

Equal Employment Opportunity

Xcimer Energy is proud to be an Equal Opportunity/Affirmative Action Employer and is committed to attracting, retaining, and developing a highly qualified, diverse, and dedicated work force. Xcimer Energy hires and promotes people on the basis of their qualifications, performance, and abilities. We support the establishment and maintenance of a workplace that fosters trust, equality, and teamwork, in which all employees recognize and appreciate the diversity of individual team members. We provide all qualified applicants for employment and employees with equal opportunities for hire, promotion, and other terms and conditions of employment, regardless of their race, color, religion, gender, sexual orientation, gender identity, national origin/ethnicity, age, physical or mental disability, genetic factors, military/veteran status, or any other status or characteristic protected by federal, state, and/or local law. Xcimer Energy will consider for employment qualified applicants with criminal histories in a manner consistent with applicable federal, state, and local laws. For more information on “EEO Is the Law,” please see here and here.

Benefits

Xcimer offers a comprehensive benefits package designed to support employee health, well-being, and long-term success. Benefits include medical, dental, and vision coverage; basic and supplemental life insurance; short- and long-term disability; paid parental leave for employees at the time of birth or adoption; and a 401(k) with a company match of up to 6%. Eligible employees also receive equity, allowing them to share in the company’s long-term success.

Xcimer operates under a flexible Paid Time Off (ATO) approach. Rather than a fixed number of vacation days, employees are trusted to take the time they need to rest and recharge while meeting the expectations of their role and team. In addition, employees receive paid sick time, 13 company-paid holidays, and an annual paid company shutdown. Benefits are available to regular employees, including part-time and fixed-term roles, as well as interns, with eligibility varying by benefit.

Responsibilities

Perform comprehensive non-sequential ray tracing (primarily using FRED software) to analyze stray light, ghost reflections, scattering, and diffraction in high-energy DUV laser systems.

Identify and mitigate high-fluence "hot spots" and fringing effects to prevent optical damage and ensure system longevity.

Implement and evaluate mechanical feature models (such as baffles, apertures, and beam dumps) within non-sequential environments to actively mitigate stray light.

Write and maintain custom scripts (e.g., Python, MATLAB, or FRED script) to automate ray trace simulations, process large datasets, interface to other analysis tools and quantify system-level signal degradation.

Collaborate cross-functionally with sequential optical designers to optimize system layouts for stray light performance.

Work closely with opto-mechanical engineers to design and validate physical stray light mitigation hardware.

Partner with material scientists to evaluate Bidirectional Scattering Distribution Functions (BSDF/BRDF), surface roughness, and specialized UV-resilient absorptive coatings/materials.

Collaborate with Optical Systems Engineers to ensure stray light requirements are defined, met, and verified at the system level for ICF applications.

Qualifications

Education: B.S. or M.S. degree in Optical Engineering, Physics, or a closely related field.

Experience: 5+ years of dedicated experience in stray light analysis and non-sequential optomechanical modeling.

Expert-level proficiency in non-sequential optical design software, with a strong preference for FRED.

Demonstrated experience writing scripts to automate optical analysis and process ray trace data.

Strong understanding of stray light mitigation techniques, including the implementation of mechanical features (baffles, beam dumps) in optical models.

Solid foundation in physical optics, scattering (BSDF/BRDF), and diffraction.

Proven ability to work in a cross-collaborative environment with multi-disciplinary engineering teams.

Must be a U.S. citizen or national, U.S. permanent resident (current Green Card holder), or lawfully admitted into the U.S. as a refugee or granted asylum.