Description
- Abstract:
- All physical measurements are inherently noisy. In situations where signals are weak, for example, in the case of spectroscopy of weak emitters and particle localization experiments, low signal to noise is particularly challenging. In these cases, it is interesting to consider the measurement schemes that would optimize the amount of information obtained under time constraints. This thesis illustrates the design of experiments under low signal conditions in three different contexts. First, we demonstrate the enhancement in photoluminescence of up to two orders of magnitude from weak silicon defects emitters proximal to all-dielectric symmetry-broken high contrast gratings. An array of photonic devices with a variety of geometrical parameters which enhances light emission into particular wavelengths and directions by modifying the local density of states are characterized. The engineered dispersions are measured through automated energy momentum spectroscopy with an InGaAs camera, which imposes a constraint in measurement time, and PL lifetime measurements with a single photon avalanche diode. Next, we investigate the optimal measurement schemes in spectroscopy under low-light conditions with regard to the use of hardware binning of pixels in charge coupled devices. We question the default single-pixel measurement scheme by using statistical analysis with tools such as the Cramér-Rao lower bound for unbiased estimators. The use of numerical techniques in pixel intensity reconstruction and peak localization in spectroscopy is also discussed. Finally, we apply these methods to a broader scientific challenge. Graduate school admission is a process complicated with inherently large variances and further restricted by limited data. With a usually long completion time, feedback information acquisition is very slow. We report a method and develop software tools for obtaining and analyzing academic outcome data for graduate students, resulting in generally an order of magnitude more data for strengthening the feedback mechanism and enabling a more thorough review of admission practices.
- Notes:
- Thesis (Ph. D.)--Brown University, 2020
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- All rights reserved. Collection is open to the Brown community for research.
Citation
Huang, Shao Ran,
"Experimental Design under Low Signal Conditions"
(2020).
Physics Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:1129383/
