High Power Interferometry

• Getting High Power

  • Laser Power has declined over the 1000's of hrs. of laser life
  • Previously could not handle the high power
  • Rebuild / Tune up lasers. Diagnose losses in the input optics.

• Detecting all the light

  • Acquisition/Detection modes: large transients / low noise
  • Dark port power split -> 4+1 photodetectors
  • Fast Mechanical Shutter to protect diodes from lock loss 'burp'
  • New gain ramping software allows smooth PD handoff

• Radiation Pressure

  • Significant torque from off center beams
  • Stage power up: Lock at low power, engage alignment controls, crank up the power
  • Software installed to compensate 'optical spring'

• Thermal Lensing

  • Deposited heat in optics forms a thermal lens (dn/dT = 10-5)
  • Active curvature correction using an external heating laser

Notes: