| For many years, particle detectors which exploit the unique properties of materials at low temperatures have been used for the detection of neutrons, alpha particles, beta particles, x-rays, gamma rays, heavy ions, and even exotic "dark matter". In all energy regimes, these devices far surpass the energy sensitivity of their room-temperature equivalents making them the detectors of choice in high-demand applications.; This thesis describes efforts toward a similar revolutionary detector system designed for the high-sensitivity measurement of near-infrared/optical/near-ultraviolet photons. Extending the superconducting transition-edge sensor (TES) technology developed for the Cryogenic Dark-Matter Search (CDMS) at Stanford University, we have designed and tested the first high-efficiency (∼50% Q.E.) broadband (250 nm--2500 nm, 5 eV--0.5 eV) optical detector capable of determining the energy of the incoming photon to a resolution of 0.15 eV FWHM giving a resolving power of R = 20 at 3 eV (equivalently, a resolution of 20 nm at ∼400 nm). These TES devices use the superconducting-to-normal transition of tungsten at around 80 mK as a sensitive thermometer to quantify the heat deposited by the individual light quanta.; This thesis describes the progress of this program from its recent inception to the present, including the design and testing of the devices, the optical and cryogenic infrastructure, and the significant experimental results to date. |
