In-vac PD/QPD layout meeting 2025/01/23
Time: Jan 23, 2025 14:00-15:00
Participants: Ray-Kuang Lee, Huali Chen, Yoichi Aso, Yuta Michimura
Zoom meeting
Minutes
- Huali showed the layout idea for AS RF and OMC REFL, with squeezing injection optics.
Add periscope to reduce the height approx. 210 mm -> 4 inch) and use smaller pedestals (footprint for 210-mm-high mirror is dia. 78 mm; see JGW-D1503916).
- Add existing AS RF in-air and OMC REFL in-air paths in the layout and see if all of them can co-exist.
- Try to simplify the layout by removing some of the steering mirrors to avoid scattered light from steering mirrors as much as possible.
- We can also add some extension plate to extend the table
- Do we really need two steering mirrors (one for piezo and one for picomotor) before each QPD?
- We can also mount disc+piezo+mirror on a picomotor mirror mount to realize both actuation with one steering mirror
A/I
- Check if OMC REFL RF QPD in-air is necessary [Michimura]
May be not. Beacon WFS is used only after locking OMC (before handing over to DC readout). LIGO is also not using OMC REFL in-air (they only have in-vac OMC REFL DC QPDs; LIGO-T1000264)
- Check what LIGO is doing for RF QPD centering (only picomotors?) [Michimura]
REFL WFS: Two tip-tilts before WFS sled, two picomotor mirrors on WFS sled LIGO-D1000313
AS WFS: Two tip-tilts (OM1, OM2) before WFS sled, two picomotor mirrors on WFS sled LIGO-D1000342 LIGO-T1200410
- Upload the slides to JGWdoc, and present the current status at the ISC meeting on Jan 27 from 15:00 JST [Huali]
- Check if OMC REFL RF QPD in-air is necessary [Michimura]
- Next meeting: TBD