Senior Scientist - Cryogenic Optical Integration (On-site)

About Xanadu:

Xanadu’s mission is to build quantum computers that are useful and available to people everywhere.

At Xanadu, we are learners, innovators, researchers, collaborators and problem solvers. We are creating something that has never been built before. Few people in their life will be able to be a part of something like this, where if we are successful, the technologies we develop will solve some of the world’s most challenging problems, and literally change the world. And that is something to be excited about!

Your role and responsibilities:

In this role, you will contribute your expertise in optics and photonics, cryogenics, and precision assembly to advance the packaging and performance of our transition edge sensors (TES). As a member of the Low Temperature Devices Team, your primary responsibility will be the development of precision cryogenic optical interfaces for photon-number-resolving TES detectors, enabling robust, low-loss coupling across thermal boundaries from room temperature to milli-Kelvin environments.

With your deep technical expertise and experience in photonic and cryogenic system development, you will play a critical role in enhancing the performance and scalability of our detector platform. This role requires significant experience with cryogenic systems, optical alignment, and photonic hardware, as well as the ability to work effectively across disciplines in a fast-paced environment.

You will design, build, and evaluate cryogenic optical coupling solutions, including fiber-to-detector alignment, fiber-ferrule and fiber-array design, thermal anchoring, and alignment repeatability. You will take full ownership of this integration, from concept through validation and deployment within large-scale detector arrays. Responsibilities include:

• Independently operate milli-Kelvin cryostats (dilution refrigerators), including cooldowns, troubleshooting, and maintenance
• Collaborate with internal and external photonics process engineers, process integration engineers, packaging engineers and technicians, including at Xanadu’s foundry partners
• Design and prototype cryogenic optical interfaces for TES detectors, including alignment stages, thermal anchoring strategies, and vacuum feedthrough coupling
• Work closely with the room-temperature packaging team to co-develop processes and create a well-defined packaging solution
• Perform cryostat-based iterative testing to validate coupling performance, repeatability and stability 
• Challenge the state-of-the-art in key performance metrics associated with cryogenic optical integration

Required qualifications and experience:

• Extensive hands-on experience operating cryostats (preferably dilution refrigerators), including cooldowns, troubleshooting, and maintenance
• Proven track record designing and implementing photonic or optoelectronic packaging in cryogenic environments
• PhD in Physics, Electrical/Mechanical Engineering, or a closely related field, with at least 2 years of postdoctoral or industry experience
• Experience with cryogenic-compatible mechanical and optical design, including fiber splicing, micron scale passive and active alignment techniques, thermal anchoring, cryogenic material properties and ultra-high vacuum techniques
• Self-motivated, comfortable working both independently and collaboratively with people of all disciplines on complex projects in a fast-paced environment
• Detail-oriented with positive attitude towards work
• Excellent interpersonal and written communication skills

Preferred qualifications and experience:

• Familiarity with TES, MKID, or SNSPD platforms and their unique cryo-optical integration challenges
• Experience writing Python code. 
• CAD and simulation experience for thermal/mechanical modeling (e.g., Solidworks, COMSOL)
• Familiarity with non-destructive imaging techniques and metrology methods such as X-ray microscopy
• Experience with a variety of wire bonding tools and applications
• Familiarity with analog test equipment (e.g., VNA, SMU) 
• Experience with statistical process control and  quality management system reporting methods

Our values are important. They are fundamental and lay the foundation for culture at Xanadu. Learn more about our values here.

At Xanadu, we are committed to building an inclusive, safe, and equitable culture and fostering an environment where our employees feel included, valued, and heard. We are committed to meeting the needs of all individuals and support a barrier-free workplace. Should you require accommodations at any point during the recruitment process please contact Recruiting at recruiting@xanadu.ai.

Note: Xanadu will never ask you for bank account information as part of the interview process. Please report any suspicious activity to recruiting@xanadu.ai.