Optical Bench Interferometer


Optical Bench Interferometer for the LISA Pathfinder mission (courtesy of University of Glasgow and University of Birmingham)

Technology abstract

A major research-led UK university has developed a space-qualified optical bench interferometer that is now being used to detect gravitational waves for ESA's LISA Pathfinder mission. The laser interferometer provides extremely precise measurements of the distance between two objects, such as the identical gold-platinum cubes at the heart of the LISA Pathfinder spacecraft. The interferometer provides picometre stability length measurements for precision metrology applications.

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Technology Description

The optical bench interferometer is a compact, rugged, optical assembly that is currently being used to detect gravitational waves as part of ESA's hugely successful LISA Pathfinder mission. The interferometer was built and tested by the University of Glasgow, a major research-led university in the UK. 
The optical bench consists of a 200mm x 212mm x 22.5 mm baseplate of Zerodur ceramic glass with 22 precision-located optical components that are bonded to the surface using hydroxide catalysis bonding. Fused silica mirrors and beamsplitters are used to reflect the beams.  

Innovations & Advantages

  • Precision aligned all-glass interferometer with absolute laser beam alignment at the few tens of microradian level
  • Picometre stability length measurements in the milliHertz regime
  • Novel custom fibre coupler design
  • Space qualified construction techniques

Further Information

Current and Potential Domains of Application

Detection of gravitational waves aboard the LISA Pathfinder spacecraft.

  • Precision metrology
  • Interferometric assemblies
  • Composite structures
  • Ground-based astronomy applications, including fine resolution imaging, solar observations, and gravity wave analysis
  • High precision measurements