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Entry  Mon Sep 20 14:08:18 2021, shruti, Update, PSOMA, in-air cantilever cavity 6x
    Reply  Tue Sep 21 10:53:01 2021, shruti, DailyProgress, PSOMA, in-air cantilever cavity 
Message ID: 2815     Entry time: Mon Sep 20 14:08:18 2021     Reply to this: 2817
Author: shruti 
Type: Update 
Category: PSOMA 
Subject: in-air cantilever cavity 

In short: Between Friday and today, I de-bonded the mirror from the broken cantilever, picked two cantilevers and bonded both the mirrors to them with the AR surface being the one on the bond side, clamped and mounted on a post one of these cantilevers, and placed it in the cavity replacing one of the flat mirrors (M3).

1. De-bonding from broken cantilever

For this, I used methanol and soaked it for around 30 min similar to the procedure here. Since this bond was weaker, it took lesser time.

2. Bonding both mirrors to cantilevers

I picked one cantilever from the previous collection and another from the dish shown in Attachment 1. This second cantilever did not seem to have the back surface passivated with SiNx and looked like it was just oxidized silicon.

I used the GE cryo-varnish at four points around the mirror placed on the etched edge of the cantilever for both and let it dry for a few hours (Attachment 2). The bonding was performed such that the AR surface was on the side of the cantilever.

3. Clamping and aligning

Using the alignment jig on the table, I picked the cantilever without the SiNx passivation on both sides (identifiable as with one non-glossy side) to mount to the clamp. I tightened it not too strongly and then used a 3/4" post of suitable height to get the center of the mirror to a height 4" from the table.

I placed it roughly where I thought it should be on the table replacing the flat mirror M3 from the previous setup. I got the beams from two round-trips to overlap visually and added a PDA10CS to look at the transmission from the cantilever.

The aim now is to do as we did earlier - sinusoidally change the temperature by driving the TEMP TUNE input with a function generator and slowly tweak the alignment of the steering mirrors to find the cavity resonance.


I also measured the transmission of the cantilever as roughly 0.1% using the power meter.

Attachment 1: source.pdf  17.057 MB  | Hide | Hide all
Attachment 2: twobondedcantilevers.pdf  12.927 MB  | Hide | Hide all
Attachment 3: clampingalign.pdf  16.408 MB  | Hide | Hide all
Attachment 4: clamped.pdf  16.895 MB  | Hide | Hide all
Attachment 5: cantileverincav.pdf  18.639 MB  | Hide | Hide all
Attachment 6: cantileverincav1.pdf  19.865 MB  | Hide | Hide all
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