writings
Time and Frequency Domain Optical Coherence Tomography: This is a result of my research at Harvey Mudd during Summer 2011. Frequency domain optical coherence tomography allows for in-vivo nondestructive imaging at speeds two orders of magnitude faster than time domain methods while increasing the signal to noise ratio. These benefits are the result of acquiring information on all scatterers in a depth scan all the time. I explore methods of maintaining depth resolution through dispersion compensation and lateral resolution and signal to noise ratio through slab-based OCT and Bessel beams, and I examine methods of resolving the complex conjugate ambiguity. I investigate ISAM and its ability to dynamically refocus data in software, and look at ways of maintaining the phase stability necessary for motion sensitivity. I calculate what specications a hypothetical instrument would have compared to our current designs.
Adaptive GPU-Accelerated Software Beacon Processing for Geospace Sensing: The final paper of my Research Experience for Undergraduates (REU) at MIT's Haystack Observatory. Radio beacons on satellites can be used in conjunction with ground receivers to study the ionosphere. The flexibility of new wideband tuners and digital receiver platforms requires a modular, adaptable software chain to optimally process and interpret beacon overflight data. A python-based system was developed to track the beacon, filter noise and convert the signal to baseband. The slow but intrinsically parallel nature of the process led to large performance gains when methods were ported to the Graphical Processing Unit (GPU) using a python wrapper of NVIDIA's CUDA programming language. This paper will discuss methodologies to port algorithms to GPU execution as well as show results for representative beacon overflights in the Westford, MA vicinity.
On the Use of a Michelson Interferometer to Determine Indices of Refraction: The index of refraction of helium gas was measured by recording the number of fringes traversing the output of a Michelson interferometer as the helium pressure in an optical cell increased. The LabView code was extended to use a remote clicker to more accurately identify the pressure in the chamber. Using a Python algorithm to compute the number of fringes between data points, the index of refraction of helium was determined to be 1+(36.01±0.06)×10^-6. The relation between pressure and time was determined to correspond closely to that of compressible isothermal flow. Using the additional pressure data and a new Fourier transform analysis, more accurate results for the index of refraction of helium, 1 + (35.98 ± 0.05)×10^-6 were determined.
Modelling The Restricted 3-Body Problem: Though the 3-body problem is difficult to solve, it can be modeled if one mass is so small that its effect on the other two bodies is negligible. This situation occurs in real-life where a binary star system, such as the one formed by the gravitationally bound stars α Centauri A and B, traps a low mass planet. The computed model correctly predicted elliptical orbits for the stars, as well as S-type and P-type orbits for a planet. This paper analyzes the range of stable planetary orbits and investigates the impact of a binary star on a distant planet relative to a single star of equal mass, and the effect such a planet would feel orbiting around one star due to the other star.
Investigating the Relationship Between Cavendish Temperature Fluctuation and Torsional Oscillation: The Cavendish apparatus measures the gravitational attraction between lead weights and a torsional pendulum to determine the value of the gravitational constant G. I developed an automated data acquisition system using a webcam and image processing in Python, which enabled me to see an interesting long-term trend in the data caused by the building's air conditioning system.
Music in a Midsummer Night's Dream: This was an essay composed for a class called "Shakespeare in Film." I analyze how two directors used Mendelssohn's famous score to emphasize different facets of the play.
Sophomore Physics Lab Tech Report: While a light bulb does not obey Ohm's law at high currents, there is a theoretical ohmic region at low currents. The resistance of the lightbulb at room temperature was calculated to be 5.13 ± 0.10, the dominant error arising from the ambient temperature fluctuations around the apparatus. The calculated temperature of the filament at the bulb's maximum rated current was 2540 ± 40 K, so only 5.2 ± 0.4% of the light emitted was in the visible spectrum.