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 Pulsed Power Physicist, you will work on the science and engineering of electron-beam cathode systems for Xcimer's pulsed power driven inertial fusion energy program. The core goal is maximizing beam efficiency and energy deposition on target. You will lead cathode development across multiple emitter technologies , design and optimize hibachi foil/anode structures for beam transport, and build complex experimental systems from concept through commissioning. This role carries significant independent scientific responsibility. We want someone who is strong in both theory and experiment and rigorous about documentation.
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
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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
Optimize beam efficiency and energy deposition on target
Lead design, fabrication, and testing of cathode systems across multiple emitter technologies (explosive emission, thermionic, photocathodes)
Design and optimize hibachi foil/anode grid structures for beam transport efficiency
Lead experimental campaigns end-to-end
Develop and validate cathode and beam transport models (analytical, PIC, SPICE) to guide design decisions; roughly equal balance of modeling and experimental work
Operate and maintain UHV vacuum systems (target < 10^-9 Torr) including bakeout, leak checking, and pumping systems
Survey prior art on emitter technologies, beam transport, and cathode physics
Own experimental program documentation: test reports, design records, operating procedures, and data management
Manage hardware procurement, BOM tracking, and vendor relationships for cathode subsystems
Interface with potential commercial emitter suppliers on procurement, packaging, and quality
Support integration of cathode systems into larger diode and laser architectures
Qualifications
Education: PhD in physics, electrical engineering, or closely related field (MS with exceptional relevant experience considered)
Experience: 5+ years of industry experience
Deep expertise in beam diagnostics (Faraday cups, beam imaging, energy analysis, calorimetry)
Hands-on experience with vacuum electronics and electron-beam generation
Able to independently design experiments, interpret results, and write up findings clearly
Experience building and commissioning complex experimental systems end-to-end (mechanical, electrical, vacuum, controls)
Familiarity with high-voltage pulsed power systems (100 kV+)
Proficiency with lab instrumentation (SMUs, oscilloscopes, HV power supplies)
Comfortable working across mechanical, electrical, and physics domains in a small team
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.
Desired
Direct experience with explosive emission, or cold cathode technologies
Familiarity with semiconductor fabrication processes
Experience with PIC or beam optics simulation codes (e.g., Chicago, CST, COMSOL)
Background in beam transport optimization
Track record of thorough technical documentation and hardware program management (procurement, scheduling, vendor coordination)
Background in excimer laser or inertial fusion energy systems