OSE Dissertation Defense by Mr. Forrest Hubert on Super-Resolution Microscopy with Color Centers in Diamond

Departmental News

Mr. Forrest Hubert 225x300

Posted: May 22, 2023

Date, Time and Location:

Thursday, June 1, 2023, from 10:00 AM to 11:30 AM at PAIS, Room 2540

Dissertation Committee:
Dr. Victor Acosta, Committee Chair, of the Physics & Astronomy Department 
   
Dr. Francisco Becerra Chavez of the Physics & Astronomy Department 
 
Dr. Terefe Habteyes of the Department of Chemistry and Chemical Biology
 
Dr. Keith Lidke of the Physics & Astronomy Department
 
Abstract:

This dissertation explores the development and application of diamond color centers, specifically the silicon-vacancy (SiV) and nitrogen-vacancy (NV) centers, in advancing super-resolution microscopy and magnetic imaging techniques. This research contributes to the field of super-resolution microscopy by demonstrating the potential of these color centers as photostable fluorophores and sensitive magnetic sensors.

The first part of this research demonstrates the application of SiV centers as fluorophores in stimulated emission depletion (STED) microscopy. Here, we show that negatively-charged silicon-vacancy (SiV) centers in diamond are promising fluorophores for STED microscopy, owing to their photostable, near-infrared emission and favorable photophysical properties. A home-built pulsed STED microscope was used to image shallow implanted SiV centers in bulk diamond at room temperature. We performed STED microscopy on isolated SiV centers. We observed a lateral full-width-at-half-maximum spot size of 89 ± 2 nm, limited by the low available STED laser pulse energy (0.4 nJ). For a pulse energy of 5 nJ, the resolution is expected to be ∼20 nm. The microscope can resolve SiV centers separated by ≲ 150 nm that confocal microscopy cannot resolve.

The second part of the research presents an innovative method for nanoscale magnetic microscopy using the NV center in diamond. This method combines charge state depletion (CSD) microscopy and optically detected magnetic resonance (ODMR) to image magnetic fields produced by 30 nm iron-oxide nanoparticles. The achieved resolution is less than 100 nm, and the microscope can resolve the magnetic field patterns from nanoparticles spaced as close as ∼190 nm. This method also enhances the magnetic field amplitudes, achieving more than an order of magnitude improvement over confocal microscopy, which can be attributed to the proximity of the sensing voxels. Despite some performance limitations due to diamond second-order Raman emission and imperfect NV charge-state control, this method introduces a new, efficient format for nanoscale magnetic imaging.

Together, these findings underscore the versatility and potential of diamond color centers in advancing super-resolution microscopy and nanoscale magnetic imaging.

Bio:

Forrest received his bachelor's degree in physics from Brigham Young University - Idaho in 2015. During his time there he did an internship at the University of Alabama at Birmingham where he did research in condensed matter physics growing nanodiamond. He is now a PhD student at the University of New Mexico in the Optical Sciences and Engineering program studying quantum optics. Since May 2016, Forrest has been working on nanophotonics with Silicon Vacancy centers and super-resolution microscopy.