<B>Abstract:</B>
We have fabricated tightly packed arrays of lumped-element Microwave Kinetic Inductance Detectors (MKID) with ~250 pixels for the far-infrared 350 ?m band using a single layer of 20-40 nm thick TiN on silicon. The resonators have meandered or spiral inductors and interdigitated capacitors with resonance frequencies of ~ 2 GHz separated by ~ 1 MHz in frequency, and ~ 65 um in space. Measurements indicate a large scatter in quality factor almost certainly due to unwanted multi-resonator modes arising from coupling between resonators. Pump-probe experiments reveal crosstalk as large as 70%, and electromagnetic simulations reproduce the observed distribution of mode frequencies across the array. We have designed and measured new resonators that have shielded electrodes resulting in very low crosstalk levels (<2%). Details of designs, experimental data, electromagnetic simulations, and a simple circuit model predicting the crosstalk will be presented.

Light refreshments will be served after the seminar.