What I did

• Modified the beam path of TEM00
• Measured the beam profile of TEM00 mode
• Adjusted the polarization of TEM00
• Started the installation of stage inside the chamber

Modification of optical path

As I replaced some screws before, I had to modify the beam path of TEM00 mode a little bit.
I aligned the EOM and lens after that in order to inject the beam into Faraday Isolator.

Measurement of TEM00 beam profile

After aligned the beam, I measured the beam profile of TEM00 which will be used for mode matching.
The result will be shown tomorrow.

Adjustment of polarization

Then I re-installed the Faraday isolator which is used for picking off the reflected beam for PDH locking.
So far, the polarization of TEM00 was adjusted to P-pol which is not appropriate one.
So I changed the polarization of TEM00 from P-pol to S-pol.
Now that TEM00 beam has S-pol.
HOMs' beam have P-pol.

Installation of stage

As the beam height from the table of cryostat chamber is too high (about 160 mm), I designed the stage for compensation.
Since some parts were delivered, I started the installation of this stage as shown in attached picture.

Next step

• Modify the layout where close to the chamber
• Assemble the folded cavity