three measurements: optical wavelength ( l mod opt ) phase measurement
DESCRIPTION
Laser ranging at the nm precision level: The two mode interference measurement in the Iliade rangemeter. Duy-Hà Phung, Clément Courde, Michel Lintz L aboratoire ARTEMIS, OCA Nice Christophe Alexandre Laboratoire CEDRIC-LETITIA, CNAM, Paris [email protected]. - PowerPoint PPT PresentationTRANSCRIPT
M.Lintz, Télémétrie Laser Atelier Télescopes NG 27-28/03/2012 1
Laser ranging at the nm precision level:
The two mode interference measurement in the Iliade rangemeter
Duy-Hà Phung, Clément Courde, Michel LintzLaboratoire ARTEMIS, OCA Nice
Christophe AlexandreLaboratoire CEDRIC-LETITIA, CNAM, Paris
M.Lintz, Télémétrie Laser Atelier Télescopes NG 27-28/03/2012 2
Three measurements:
Optical wavelength (L mod opt) phase measurement (highest resolution, < nm)
+ Synthetic wavelength (L mod ) phase measurementat µ-wave frequencies: interm. length scale, to <<10-4 cycle
+ Time-of-flight measurement
Iliade: combination of three length scales
long-term phase drifts in microwave components >> 10-4 cycle!
samesignal
collab. Etienne Samain, GéoAzur, OCA
Stéphane Pitois, ICB, Univ. Dijon
M.Lintz, Télémétrie Laser Atelier Télescopes NG 27-28/03/2012 3
/)(2cos Lct
/)2
(2cos/)(2cos2lL
ctL opt
/)(2cos2 ct
Iliade: optical- and synthetic-length scales in one signal
/)(2 lLphase
meas. ²
4 interf.
complex signal (helps identification of systematics)rather complex set-uprather complex proceduredifficulties related with AM-to-PM coupling (thermal transients in the measurement photodiode) due to amplitude variations
resolution 100pm @150µs, improves as 1/expected accuracy: nm
L - scan
complex plane plot of the signal
microwave opt.-beat-note