David Bracher
David Bracher, Ph.D.
Scientist
Electrical Engineering & Computer Science
Chicago - Downtown

Dr. Bracher has a background in solid-state physics and nanoscale photonics. His research experience includes simulation, fabrication, and characterization of nano-photonic devices in wide-bandgap semiconductors. At Exponent, he has assisted clients with both intellectual property matters and failure analysis related to vehicle systems.

Dr. Bracher completed his Ph.D. in physics at Harvard University. His research focused on integrating atom-like defects in diamond and silicon carbide within photonic crystal cavities, a form of optical cavity. These defects are of interest for their application to solid-state quantum computing and quantum sensing platforms. This work required the use of a variety of semiconductor fabrication and characterization techniques within a state-of-the-art cleanroom. Specifically, Dr. Bracher has extensive experience with electron beam lithography, photolithography, reactive ion etching (RIE), chemical and physical vapor deposition (CVD & PVD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Additionally, micro-photoluminescence (PL) and Raman spectroscopy measurements were used to optically characterize fabricated devices. As a result, he is practiced in setup and maintenance of micro-PL systems and in the use of these systems for spectroscopy, time-resolved measurements, and photon-correlation measurements (e.g. HBT interferometry). Through this work, he also developed familiarity with high-vacuum systems.

Complementary to fabrication and characterization, Dr. Bracher has significant experience in device simulation. He used commercial software to perform finite-difference time domain (FDTD) electromagnetic simulations of a wide array of photonic devices and to simulate 1D- and 2D-band structures of semiconductor heterojunctions in order to improve a photoelectrochemical (PEC) etching process in silicon carbide. Furthermore, he has experience with standard scientific computing techniques, including both numerical and stochastic methods and machine learning algorithms. He is proficient in programming with MATLAB and has additional familiarity with Python and C.

As a graduate student, Dr. Bracher’s teaching was recognized with numerous awards from the Harvard Bok Center for Teaching and Learning and Physics department. His teaching experience includes serving as the graduate teaching assistant for an extensive course on analog and digital laboratory electronics, as well as for physics classes on mechanics and thermodynamics and on electromagnetism and optics for pre-medical students. Beyond this work, he served for two years as the head teaching consultant for the Harvard Physics department.

CREDENTIALS & PROFESSIONAL HONORS

  • Ph.D., Physics, Harvard University, 2017
  • A.M., Physics, Harvard University, 2013
  • A.B., Physics, Harvard University, 2011
  • Phi Beta Kappa honor society

Publications

Bracher DO, Zhang X, Hu EL. Selective Purcell enhancement of two closely linked zero-phonon transitions of a silicon carbide color center. Proceedings of the National Academy of Sciences; 2017; 114 (16), 4060-4065.

Bracher DO, Hu EL. Fabrication of high-quality nanobeam photonic crystal cavities in 4H silicon carbide with embedded color centers. Advances in Photonics of Quantum Computing, Memory, and Communication IX, Proc. of SPIE 2016; 9762, 97620Z.

Bracher DO, Hu EL. Fabrication of high-Q nanobeam photonic crystals in epitaxially grown 4H-SiC. Nano letters 2015; 15 (9), 6202-6207.

Cui S, Zhang X, Liu T, Lee J, Bracher DO, Ohno K, Awschalom D, Hu EL. Hybrid plasmonic photonic crystal cavity for enhancing emission from near-surface nitrogen vacancy centers in diamond. ACS Photonics 2015; 2 (4), 465-469.

Lee JC, Bracher DO, Cui S, Ohno K, McLellan CA, Zhang X, Andrich P, Aleman B, Russell KJ, Magyar AP, Aharonovich I, Jayich AB, Awschalom D, Hu EL. Deterministic coupling of delta-doped nitrogen vacancy centers to a nanobeam photonic crystal cavity. Applied Physics Letters 2015; 105, 261101.

Magyar AP, Bracher DO, Lee JC, Aharonovich I, Hu EL. High quality SiC microdisk resonators fabricated from monolithic epilayer wafers. Applied Physics Letters 2014; 104, 051109.

Aharonovich I, Lee JC, Magyar AP, Bracher DO, Hu EL. Bottom-up engineering of diamond micro- and nano-structures. Laser and Photonics Review 2013; 7 (5), L61-L65.

Lee JC, Magyar AP, Bracher DO, Aharonovich I, Hu EL. Fabrication of thin diamond membranes for photonic applications. Diamond and Related Materials 2013; 33, 45-48.

Presentations

Bracher DO, Hu EL. Resonant enhancement of Silicon Vacancy Centers in 4H-SiC with photonic crystal cavities. META International Conference on Metamaterials, Photonic Crystals, and Plasmonics; Malaga, Spain, July 2016.

Bracher DO, Hu EL. High-Q 4H-SiC photonic crystal cavities with integrated defect centers. Advances in Photonics of Quantum Computing, Memory, and Communication IX, Photonics West; San Francisco, CA, February 2016.

Bracher DO, Hu EL. 4H-SiC photonic crystal cavities with Q ~ 7,000 at visible wavelengths. Quantum Photonics, Information Technology and Sensing, MRS Spring; San Francisco, CA, April 2015.

Prior Experience

Graduate Research Assistant, Harvard University, 2012-2017

Undergraduate Research Assistant, Harvard University, 2008-2011

Helios Scholar, Translational Genomics Research Institute, Neurogenomics Division, 2007, 2008

Intern, Translational Genomics Research Institute, Neurogenomics Division, 2006-2007

Professional Affiliations

Optical Society of America, Member

Materials Research Society, Member

Additional Information

Peer Reviewer

Applied Physics Letters

Nano Letters

CREDENTIALS & PROFESSIONAL HONORS

  • Ph.D., Physics, Harvard University, 2017
  • A.M., Physics, Harvard University, 2013
  • A.B., Physics, Harvard University, 2011
  • Phi Beta Kappa honor society