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!
Join Xcimer’s engineering internship program and gain hands-on experience in designing and building cutting-edge laser-driven inertial fusion hardware and software. As a summer intern, you will be integral to developing the systems needed for the world’s first commercial fusion energy power plant. We have multiple internship opportunities available across various disciplines, including Mechanical Engineering, Electrical Engineering, Physics, and Software Development. Please apply to the posting that best matches your background and interests.
During this 12-week program at our headquarters in Denver, CO, you’ll work alongside an industry expert mentor to tackle complex, real-world challenges in fields such as structures, mechanisms, optics, pulsed power, computational engineering, plasma physics, and manufacturing. We are seeking interns who are passionate about applying their technical skills, problem-solving abilities, and commitment to quality to drive the future of clean energy!
Application close date: 12/31/2026
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
Benefits Employee Benefits include: Medical, dental, vision, basic and supplemental life insurance, paid parental leave (must be employed at time of birth or adoption), short and long-term disability, 401(k) with a company match of up to 6%. Paid Time Off: 15 days per year based on weekly scheduled hours, 10 paid sick leave, and 13 company-paid holidays for all regular employees (including part-time), fixed-term, and interns. Equity will be granted to eligible employees. Equity is designed to allow employees to share in company results and success.
Responsibilities will vary depending on each intern's are of expertise and interests
Mechanical design and hardware development
Mechanical and thermal analysis using finite element analysis
Systems engineering
Manufacturing engineering
Electrical engineering (pulsed power)
Control systems engineering
Computational and software engineering (simulations)
Nuclear engineering
Optical engineering
Plasma physics
Qualifications
Qualified candidates must be enrolled in a Bachelor's, Master’s or PhD degree program from an accredited college or university in mechanical engineering, electrical engineer, physics, nuclear engineering, or other related engineering discipline.
Application of technical skills outside of the classroom (examples include: extracurricular projects, volunteering, personal projects, laboratory research, or prior internship/work experience).
Proficiency in CAD software for 3D modeling and simulation.
Strong written, verbal, communication, and interpersonal skills.
Passion for fusion energy!
Ability to work full-time onsite through the duration of the 12 week internship program in Denver, CO.
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 of granted asylum.