|
40m
QIL
Cryo_Lab
CTN
SUS_Lab
CAML
OMC_Lab
CRIME_Lab
FEA
ENG_Labs
OptContFac
Mariner
WBEEShop
|
| 40m Log |
Not logged in |
 |
|
|
 Mon May 2 17:11:55 2016, rana, Update, COC, RC folding mirrors
|
 Wed May 18 01:10:22 2016, gautam, Update, COC, Finesse modelling 
| |
Tue May 24 22:49:02 2016, gautam, Update, COC, Finesse modelling - mode overlap scans 9x
| |
Tue May 24 23:17:37 2016, ericq, Update, COC, Finesse modelling - mode overlap scans
| |
Thu Jun 16 15:57:46 2016, gautam, Update, COC, Contrast as a function of RoC of ETMX
| |
Thu Jun 16 18:42:12 2016, rana, Update, COC, Contrast as a function of RoC of ETMX
| |
Thu Jun 16 23:02:57 2016, gautam, Update, COC, Contrast as a function of RoC of ETMX
| |
Mon Jun 20 01:38:04 2016, rana, Update, COC, Contrast as a function of RoC of ETMX
| |
Mon Jun 20 18:07:15 2016, gautam, Update, COC, Contrast as a function of RoC of ETMX
| |
Tue Jun 28 16:06:09 2016, gautam, Update, COC, RC folding mirrors - further checks
| |
Thu Jun 30 16:21:32 2016, gautam, Update, COC, Sideband HOMs resonating in arms
| |
Sat Aug 13 18:25:22 2016, gautam, Update, COC, RC folding mirrors - Numerical review
| |
Tue Aug 16 11:51:43 2016, gautam, Update, COC, RC folding mirrors - Numerical review
| |
Tue Aug 16 16:38:00 2016, gautam, Update, COC, RC folding mirrors - Numerical review
| |
Wed Aug 17 14:37:36 2016, gautam, Update, COC, RC folding mirrors - Numerical review
| |
Wed Aug 17 16:28:46 2016, Koji, Update, COC, RC folding mirrors - Numerical review
| |
Mon Nov 21 15:34:24 2016, gautam, Update, COC, RC folding mirrors - updated specs
| |
Thu Feb 23 10:59:53 2017, gautam, Update, COC, RC folding mirrors - coating optimization
| |
Tue Mar 14 10:56:33 2017, gautam, Update, COC, RC folding mirrors - coating optimization
| |
Mon Apr 10 15:37:11 2017, gautam, Update, COC, RC folding mirrors - v3 of specs uploaded 8x
|
|
|
Message ID: 12413
Entry time: Tue Aug 16 11:51:43 2016
In reply to: 12407
Reply to this: 12414
|
| Author: |
gautam |
| Type: |
Update |
| Category: |
COC |
| Subject: |
RC folding mirrors - Numerical review |
|
|
Summary of roundtable meeting yesterday between EricG, EricQ, Koji and Gautam:
We identified two possible courses of action.
- Flip the G&H mirror (PR2/SR2) back such that the (convex) HR face is the right way round. We want to investigate what are the requirements on a new PR3/SR3 optic that will guarantee cavity stability and also give good mode matching.
- Order two new sets of mirrors (i.e. replace all 4 folding mirrors). In this case, we want to spec a flat (how flat is reasonable to specify? EricG will update us) PR3/SR3, and design a PR2/SR2 with some concavity that will guarantee cavity stability in the event PR3/SR3 deviates from flatness (but still within what we spec). The choice to make PR3 as close to flat as possible is because the angle of incidence in our arrangement means that any curvature on PR3 dominates astigmatism.
I have done some calculations to evaluate the first alternative.
- Based on yesterday's preliminary discussion, we felt it is not reasonable to spec mirrors with RoC > 4km (sag of ~80nm). So I restrict my analyses to the range 300m-4km
- Koji has a measurement of the phase maps for the G&H mirrors. The measured curvature is ~-500m. In my simulations, I've tried to allow for error in this measurement, so I look at the range -450m to -700m for the G&H mirror.
- The Gouy phase analysis suggests we should look for an RoC of +500m (concave) for the new PR3/SR3 to have a TMS of ~1.5 MHz. Anything flatter (but still concave) means the TMS gets smaller.
- The mode-matching in this region also looks pretty good, between 98% and 99%
- I will post results of the analysis for the second alternative here for comparison
Something else that came up in yesterdays meeting was if we should go in for 1" optics rather than 2", seeing as the beam spot is only ~3mm on these. It is not clear what (if any) advantages this will offer us (indeed, for the same RoC, the sag is smaller for a 1" optic than a 2").
Attachments:
Attachment #1: Mode-matching maps between PRX and Xarm cavities, PRY and Yarm cavities with some contours overlaid.
Attachment #2: Mode-matching maps between SRX and Xarm cavities, SRY and Yarm cavities with some contours overlaid.
Attachment #3: Gouy phase calculations for the PRC
Attachment #3: Gouy phase calculations for the SRC
|
|
|
|
|
|
|
|