Undergraduate Honors Theses

Thesis Defended

Spring 2019

Document Type


Type of Thesis

Departmental Honors


Engineering Physics

First Advisor

Cindy A. Regal

Second Advisor

Jun Ye

Third Advisor

Yung Chen Lee


Within the field of nuclear magnetic resonance (NMR), it has long been considered that using force-based detection instead of a pick-up coil for electromagnetic waves may be an intriguing way to achieve nanoscale resolution for detection of nuclear spins. This idea, known as magnetic resonance force microscopy (MRFM), is nonetheless a very difficult experimental proposition due to the extreme sensitivities necessary. Silicon nitride membrane resonators are one potential way that we want to explore increasing the force sensitivity of MRFM devices and improving imaging resolution. Specifically, engineered silicon nitride resonators may have lower surface noise effects due to higher frequencies and reduced force noise floors do to high quality factors. In my thesis, we took a first step towards this goal, demonstrating observation of magnetic resonance of electron spins in DPPH (a spin sample that is easier to detect both in concentration and gyromagnetic ratio) and achieve force sensitivities as low as 67 aN/Hz. Additonally, future membrane resonators are introduced that hint at force sensitivities as low as 0.6 aN/Hz with resonant frequencies above 1 MHz. Finally, discussion is opened around the integration of MRFM devices into an optical cavity, for which silicon nitride membrane resonators as used in the Regal group are aptly fit. Benefits of cavity optomechanical integration lie in passive damping of the mechanics to increase measurement bandwidth and improved detection sensitivity.

Available for download on Saturday, October 03, 2020