Michael and Yuhang

When IR phase shifter (IRPS) is driven, an obvious misalignment could be found in the IRMC scanning spectrum. In this elog, we report the detail of misalignment when IRPS is given different level of high voltage.

Experimental setup: IRMC is scanned to have two TEM00 peaks within one slope of ramp signal. The IRPS is located before IRMC and given an 75V high voltage at the beginning. We changed the high voltage level and took scanning spectrum accordingly. The measurements were done with the following high voltage

We got scanning spectrum as attached figure 1. It is clear from figure 1 that almost only TEM01 mode appears after IRPS is given different high voltage.

According to the peak values in figure 1, we extract the percentage of power goes to TEM01 as figure 2.