Kumar, Shwetank (2008) Submillimeter wave camera using a novel photon detector technology. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-05072008-075138
Cryogenic photon detectors can be used to make extremely sensitive cameras for submillimeter astronomy. Current detector technologies already have sensitivities limited by the noise due to photon arrival statistics. To further improve the sensitivity and mapping speed of experiments for a wide field survey, focal planes containing tens of thousands of pixels are required. Unfortunately, the current technologies use discrete and massive components which are not easy to integrate into large arrays. This thesis presents a 16-pixel, two-color, submillimeter-wave, prototype camera developed at Caltech and the Jet Propulsion Laboratory using a novel photon detector technology. The camera also uses new designs for other constituent elements – the antenna, transmission line feednetwork, and bandpass filters – to implement the sub-millimeter pixels. These designs allow integration of the entire camera onto a single chip and conclusively address the problem of scalability while maintaining the sensitivity and noise performance of the current technologies. This thesis explains the design of each of these components and presents the results from experiments conducted to test their performance. Results from the ’first light’, obtained by mounting the prototype camera onto the Caltech Submillimeter Observatory (CSO), are also presented.
We have also studied the temperature and power dependence of the resonance frequency, quality factor, and frequency noise of the superconducting niobium thin-film coplanar waveguide (CPW) resonators in order to understand the factors affecting the noise performance of our photon detectors. These experiments were carried out at temperatures well below the superconducting transition (Tc = 9.2 K) in an attempt to understand the source of the excess frequency noise of superconducting resonators which form the sensing element of our photon detectors. The noise decreases by nearly two orders of magnitude as the temperature is increased from 120 to 1200 mK, while the variation of the resonance frequency with temperature over this range agrees well with the standard two-level systems (TLS) model for amorphous dielectrics. These results support the hypothesis that TLS are responsible for the noise in superconducting microresonators and have important implications for resonator applications such as qubits and photon detectors.
|Item Type:||Thesis (Dissertation (Ph.D.))|
|Subject Keywords:||bandpass filters; superconducting resonators|
|Degree Grantor:||California Institute of Technology|
|Division:||Engineering and Applied Science|
|Major Option:||Applied Physics|
|Thesis Availability:||Public (worldwide access)|
|Defense Date:||13 December 2007|
|Author Email:||shwetank.kumar (AT) gmail.com|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Imported from ETD-db|
|Deposited On:||20 May 2008|
|Last Modified:||26 Dec 2012 02:40|
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