Reduction of degenerate modes excitation in a imperfect FP cavity for LG33 beam

Document #:

LIGO-T1100220-v1

Document type:

T - Technical notes

Abstract:

The excitation of degenerate modes in a FP cavity with imperfect mirrors can contaminate the signal when LG33 beam is used and the contrast defect degradation affects the SN ratio. In this note, artificial irregularity is placed on the mirror surface at the node radius of the LG33 field, and the reduction of the degenerate mode excitation is studied.
It is shown that these methods do suppress the degenerate mode excitation, but it is accomplished at the expense of the signal loss.

Files in Document:

• Simple summary of two methods to reduce degenerate mode excitation (T1100220-v1.pdf, 293.6 kB)

Topics:

• Core Optics
• Modelling

Authors:

• Hiro Yamamoto

Keywords:

LG33 degenerate mode excitation SIS