Summary: Recorded the presence of higher order modes in IMC
What I did: Misaligned the flat mirror MC1 by small amount in both pitch and yaw (it was needed to be done cause at the beginning of the experiment no higher order modes were present) and scanned the cavity for frequency-range 32MHz to 45MHz.
I found the presence of higher order modes around 36.7MHz (1st order) and 40.6MHz (2nd order) along with two other strong modes near 35MHz and 42.5MHz.
Please, restore condition after you finished and update elog right away! People wasted hours yesterday not knowing the condition of the MC