a) Frequency sweep across the array. Each dip in transmission corresponds to an individual resonator. The total resonator Q is dominatedby Q_c and is in the range of 10⁴ across the array as designed. The internal quality factors Q_i approach 1 × 10⁶. b) Resonance of a single LEKID responding to increasing optical power. The quasiparticle density n_qp increases with optical loading, causing a shift in f₀ and Q.