Development and test of an absorption bench to characterize the KAGRA mirrors: status report

Document #:

JGW-G1605695-v1

Document type:

G

Submitted by:

Manuel Marchio

Updated by:

Manuel Marchio

Document Created:

23 Sep 2016, 05:24

Contents Revised:

23 Sep 2016, 05:24

DB Info Revised:

23 Sep 2016, 05:24

Abstract:

The operation at cryogenic temperature strongly depends on the mirror optical absorption. For this reason, it is important to measure and minimize this mirror parameter. The experimental setup to characterize the bulk and surface absorption properties uses the photothermal commonpath interferometer method. Using proper calibrations, the optical absorption of bulk and reflective coatings is measured. To reduce mechanical losses, crystalline dielectric multilayer coating made of GaAs/AlAs has been proposed for future KAGRA upgrades. To this purpose the absorption of GaAs/AlAs coatings deposited on thin wafers needs to be measured. To improve the calibration procedure, and for a better understanding of the absorption system, numerical simulations has been made. We are currently upgrading the system to measure also larger samples, up to φ220mm x 150mm, the size of KAGRA sapphire mirrors, and to measure the GaAs/AlAs crystalline coatings.

Files in Document:

• talk_jps_2016oct24.pdf (2.0 MB)

Topics:

• Activity:KAGRA
• Detector:Optics
• Management:Conference:JPS

Authors:

• Manuel Marchio