Summer 2027 Internship - Experimental Lasers (Undergraduate)

Xcimer is hiring a Summer 2027 Internship - Experimental Lasers (Undergraduate) in Denver, CO (on-site). When: Summer 2027, 12 weeks. Posted November 12, 2026. Checked against the employer's posting on November 15, 2026.

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 12-week summer internship based at our headquarters in Denver, CO. As an Experimental Lasers Intern, you will apply your skills to building, aligning, and measuring the pulsed laser systems and diagnostics that support Xcimer's excimer laser development. You will be paired with a mentor in the Experimental Lasers group and work hands-on in the lab, on a project scoped to your background and interests. We are looking for our physicists and engineers to apply their technical expertise, problem solving skills, and dedication to quality to positively impact the future of energy!

Responsibilities • Assemble, align, and operate pulsed laser setups and optical beamlines alongside an Experimental Lasers mentor. • Build and calibrate diagnostics for pulse energy, duration, spectrum, and beam profile, and reduce the raw data to results. • Compare measurements against first-order models from textbooks and the published literature. • Help plan and run experiments on a team project, keeping clear records of setups, data, and findings. • Present your results to the team and at a company-wide Lunch and Learn at the end of the summer.

Qualifications • Education: Pursuing a BS in physics, optics, electrical engineering, or a related field, with at least sophomore year completed by summer 2027. • Experience: Hands-on lab work through an upper-division lab course, a research group, senior design, or an independent build project. • Clear written and verbal communication. • Available to work full-time onsite in Denver for all 12 weeks. • 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 • Familiarity with pulsed lasers or harmonic frequency conversion. • Exposure to pulse diagnostics such as energy meters, photodiodes, spectrometers, or beam profilers, and to analyzing the data in Python, MATLAB, or similar. • Background working around vacuum systems, high voltage, or Class 4 lasers under a safety program. • Skilled at optical alignment from a lab course, research group, or personal project.

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. 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.