Lead Experimental Physicist

Number of employees

200

Denver, CO

Posted on: 2026-04-14

Category: energy

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Employment type:

Full time

Experience required:

Intermediate

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 the Lead Experimental Physicist, you will be responsible for independently driving complex laser-based experiments from definition through execution and analysis. This role requires strong experimental physics judgment, deep interest in the underlying science, and the ability to quickly learn and master sophisticated systems. You will design experiments, develop/upgrade diagnostics, analyze and interpret data, and continuously identify opportunities to improve experimental performance. You will work closely with scientists, engineers, technicians, shot directors, and leadership, serving as the technical driver for assigned experimental programs. We are looking for our scientists and engineers to apply their technical expertise, problem solving skills, and dedication to quality to positively impact the future of energy! 

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

  • Act as the primary experimental owner for assigned laser experiments
  • Rapidly learn and develop deep understanding of complex experimental platforms, including lasers, diagnostics, and supporting subsystems
  • Design and execute experiments involving lasers, spectroscopy, imaging, and time resolved measurements
  • Develop and apply appropriate diagnostics to understand system performance and debug experimental issues
  • Translate high level scientific objectives into detailed experimental designs and test plans
  • Review experimental results critically, identify limitations, and drive systematic improvements
  • Perform quantitative post processing and analysis of spectroscopy and imaging data
  • Modify, extend, and maintain data processing and analysis scripts
  • Produce clear technical reports, presentations, and publishable quality results
  • Interface with the scientific board and senior scientists to understand experimental priorities and required outcomes
  • Collaborate closely with technicians and engineers, providing technical direction, mentoring, and training
  • Troubleshoot nontrivial experimental, diagnostic, and system level issues
  • Work effectively across disciplines, including experimentalists, theorists, engineers, and technicians
  • Qualifications

  • Education: PhD in Physics, Electrical Engineering, Applied Physics, or a closely related field, or equivalent experience
  • Strong hands-on experience with laser-based experiments
  • Solid understanding of optical and laser diagnostics
  • Demonstrated ability to independently drive complex experimental work
  • Experience debugging complex experimental systems and diagnosing root causes
  • Willingness to learn pulsed power concepts
  • Proficiency in data analysis and post processing
  • Strong written and verbal communication skills
  • High level of motivation, curiosity, and ownership mindset
  • 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
  • Desired

  • Familiarity with excimer lasers
  • Experience in laser gain dynamics
  • Experience with laser wavefront measurement
  • Experience with deformable mirrors
  • Experience with phase plates
  • Experience with gas kinetics
  • Experience with vacuum systems.
  • Experience operating and aligning pulsed laser systems
  • Experience producing scientific publications
  • Experience working in multidisciplinary research laser facilities, such as national labs
  • Experience with Matlab, Python, and LabVIEW.
  • Prior experience mentoring technicians or junior team members
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