Spring Semester 2026 Internship - Mechanical Engineering

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 an 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: 10/01/2025

• 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

• 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.

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.