AMULET Advanced Metrology Using LasEr Tracers John Dale

2 Project Aim To take Frequency Scanning Interferometry (FSI) from the lab into a product

3 Frequency Scanning Interferometry (FSI) Absolute measurements Used for several projects in Oxford –ATLAS –LiCAS –MONALISA Ratio of phase advance is equal to the ratio of the lengths Reference interferometer is an absolute length scale –Can determine D if L known Scalable –Any number of measurement interferometers Tunable Laser Reference Interferometer: L Measurement Interferometer: D Measurement Interferometer: D2 Time Intensity

4 Project Tasks Improve FSI Technique Practicality Stability Traceability Implement FSI in a laserTRACER Reduce equipment cost Simultaneous multiple length-measurements

5 LaserTRACER Developed by NPL, PTB and marketed by Etalon AG –A self tracking laser interferometer –Automatically follows retro reflector –Uses differential interferometry with a frequency stabilised laser Frequency Stabilised Laser Time Intensity

6 Why Absolute Measurement? Differential measurement –laserTRACER tracks retro reflector If Absolute measurement system added –No problems with beam breaks –Switch from one target to the next –Divergent beam allows simultaneous measurements

7 Current Reference Interferometers Evacuated folded path reference interferometers –Bulky –Expensive –Difficult to thermally stabilise We require –Compact –Can be thermally stabilised –Long term stability 1.2m

8 Compact fibre reference interferometer Fibre Reference Interferometer –Compact (Coiled) –Cheaper –Dispersion Experimental Prototype under construction –Fluid bath –Insulated –Temperature monitored Optical length with submicron stability To be developed into a product

9 LaserTRACER Implementation Install into LaserTRACER head Take advantage of: –Tracking capabilities –Stabilised construction –Market presence Many possible configurations Multiple measurement interferometers

10 Reduced Laser Cost Working with laser manufacturers –Produce simpler stripped down frequency scanning lasers. –Lasers which better suit FSI Laser is significant cost, reduction could open other markets.

11 Why are they useful Particle Accelerator/Detector Alignment CMM and CNC Calibration –Require calibration 1-4 times per year –With absolute measurement capabilities, calibration much quicker Combined CMM and CNC machines. –Absolute distance measurements capability –Especially interesting at large machines (20-30m) –Small machines if cost reduced. Metrology assisted assembly –Fitting of aeroplane wings

12 Summary Project will lead to a product: FSI enhanced laserTRACER Generate Intellectual property NPL and Etalon AG have established market presence laserTRACER has an established customer base On the market in 4-5 years