Academic Commons

Theses Doctoral

Kinetic inductance detectors for measuring the polarization of the cosmic microwave background

Flanigan, Daniel

Kinetic inductance detectors (KIDs) are superconducting thin-film microresonators that are sensitive photon detectors.
These detectors are a candidate for the next generation of experiments designed to measure the polarization of the cosmic microwave background (CMB).
I discuss the basic theory needed to understand the response of a KID to light, focusing on the dynamics of the quasiparticle system.
I derive an equation that describes the dynamics of the quasiparticle number, solve it in a simplified form not previously published, and show that it can describe the dynamic response of a detector.
Magnetic flux vortices in a superconducting thin film can be a significant source of dissipation, and I demonstrate some techniques to prevent their formation.
Based on the presented theory, I derive a corrected version of a widely-used equation for the quasiparticle recombination noise in a KID.
I show that a KID consisting of a lumped-element resonator can be sensitive enough to be limited by photon noise, which is the fundamental limit for photometry, at a level of optical loading below levels in ground-based CMB experiments.
Finally, I describe an ongoing project to develop multichroic KID pixels that are each sensitive to two linear polarization states in two spectral bands, intended for the next generation of CMB experiments.
I show that a prototype 23-pixel array can detect millimeter-wave light, and present characterization measurements of the detectors.

Files

  • thumnail for Flanigan_columbia_0054D_14426.pdf Flanigan_columbia_0054D_14426.pdf application/pdf 12 MB Download File

More About This Work

Academic Units
Physics
Thesis Advisors
Johnson, Bradley R.
Degree
Ph.D., Columbia University
Published Here
March 2, 2018
Academic Commons provides global access to research and scholarship produced at Columbia University, Barnard College, Teachers College, Union Theological Seminary and Jewish Theological Seminary. Academic Commons is managed by the Columbia University Libraries.