M.Sc Thesis

M.Sc StudentBayn Igal
SubjectHigh-Q Photonic Crystal Nanocavities on Diamond
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROFESSOR EMERITUS Yosef Salzman
Full Thesis textFull thesis text - English Version


Slab 2D photonic crystal (PC) structures in diamond are being considered as an attractive architecture for the control and manipulation of light-matter interaction in the strong coupling regime for quantum information processing devices in the solid state. In contrast to silicon, achievement of high-Q nanocavities in diamond is challenging because of the lower material dielectric constant, which results in a decreased band-gap in a diamond slab, and a lower vertical confinement, thus, limiting the design ability in tuning the quality factor. In this work recently proposed techniques for quality factor optimization are extended to the case of a diamond slab for high-Q design.

All of the designs in the current work are based on the diamond membrane suspended in air and periodically modulated in-plane with the photonic crystal structure. First, a detailed analysis of photonic crystal slabs band structure in diamond is introduced. Then, various geometrical designs of single point defects, advanced modifications to the single point defect and double heterostructures for the formation of high Q nanocavities in diamond are modeled. The highest value of vertical quality factor Qv ~ 70,000 is achieved in double heterostructures. This result seems to be significant for further consideration of photonic crystals in diamond for quantum electrodynamics applications. Following the study of double heterostructures, linear photonic crystal waveguides are discussed as well.

Finally we discuss how the lower dielectric constant influence cavity Q and perform a semi-qualitative comparison between the results in silicon and in diamond. This comparison shows a physical mechanism that stands behind lower quality factor in diamond. We tune this model with real confinement mode widths, derived from the double heterostructures, and describe the influence of mode width change on quality factors. Optimal height for the waveguide based cavity geometry is derived as well.

In addition to photonic crystal modeling, we also address the fabrication of photonic crystal slabs in diamond. The fabrication process of a diamond membrane formed by ion implantation is discussed. Then we describe the focused-ion-beam (FIB) etching technique and show the initial fabrication results. The issues pertaining to experimental set-up needed for the characterization of these structures are dwelt on.

At the end of this work we discuss several ideas for a future study in the field.