Near-field imaging of Q > 50,000 photonic ring resonators in electronics-photonics integrated CMOS platform

Despite continual progress towards higher Q photonic resonators and more accurate near-field imaging techniques, near-field imaging of high Q photonic resonators has remained a challenge to researchers due to the greatly increased tip-sample interaction^1,2,3. We present a novel technique in which we are able to successfully near-field image a Q > 50,000 resonator through careful oxide etching of the backside buried-oxide, which allows one to control the tip-sample distance and thus the tip-sample interaction. 

¹S. Mujumdar et al., Opt. Express, 15, 17214-17220 (2007)

²F. La China et al., Appl. Phys. Lett. 107, 101110 (2015)

³B. le Feber et al., Light Sci Appl 8, 28 (2019)