In-Situ Laser Mode Spectroscopy for Mirror Phase Mapping

Document #:

LIGO-T1800200-v7

Document type:

T - Technical notes

Abstract:

This project is focused on improving the sensitivity in LIGO by characterizing mirror figure error that contributes to optical losses in the laser. As a result of scattered light, optical losses increase shot noise and destroy the squeezed state of light. Surface perturbations in the mirrors will be evaluated with In-Situ laser mode spectroscopy using the 40 meter prototype laser interferometer gravitational wave detector. Mirror figure error will cause the resonant frequencies of the Hermite-Gaussian modes to shift from their ideal theoretical spacings. Mirror phase maps, a physical representation of the mirror, can be reconstructed by analyzing the shift in mode spacings with Bayesian inference. The success of aLIGO is largely due to precise optical measurements. By mapping the surface of the mirror down a precision of 1 Angstrom, the optical losses and noise can be evaluated and minimized.

Files in Document:

• Sandrine_Ferrans_final report.pdf (7.6 MB)

Other Files:

• finalpresentationligo.pdf (4.1 MB)
• finalpresentationligo1.key (6.6 MB)
• interim report 1.pdf (1.5 MB)
• interim report 2.pdf (7.0 MB)

Topics:

• Basic R&D

Authors:

• Sandrine Ferrans
• Koji Arai
• Rana Adhikari
• Gautam Venugopalan

Keywords:

SURF2018 SURF SURF18

Referenced by:

• LIGO-T1900127: Final reports from LIGO SURF program, Summer 2018

Associated with Events:

held from 23 Aug 2018 to 24 Aug 2018 in Caltech SCR, West Bridge 351, TeamSpeak