Incorporation of Nonconventional Crystalline Materials onto the Integrated Photonics Platform

Applications that span from sensing, to large bandwidth communication, to acoustic filtering, to high-resolution imaging and display, to quantum information processing (QIP) and to advance electronics have a growing need for new device types and materials. These advanced devices require electrical and optical properties that, in some cases, can only be provided by truly single-crystal thin-films of nonconventional materials, such as lithium niobate (LN, LiNbO3), yttrium aluminum garnet (YAG, Y3Al5O12) and diamond. In order to incorporate those crystals into existing multi-scale integrated system platforms, new technologies must be developed that can supply high-quality, single-crystal, thin-films in the desired thin-film architecture. Unfortunately, production of thin-films of single-crystals is not always possible via growth. Here, the use of Crystal Ion Slicing (CIS) technique to realize single-crystal thin-films of three of the nonconventional crystals is described. The fabrication techniques vary greatly between different crystals. Thus, new exfoliation chemistries must be developed for each material system. Detailed description of the investigation into exfoliation of LN, YAG and diamond is presented. The most mature CIS application is for LN crystals. Here, the development of several important complementary fabrication methods is presented. This includes description of polishing and bonding techniques that are necessary for successful incorporation of thin-films. Further, a lateral patterning technology of thin-films using femtosecond laser ablation is demonstrated. In addition, an ion-implantation patterning method and its application in nonlinear optics is presented. Finally, a novel polarization dependent plasmonic filter is described. In addition, a detailed description of the fabrication methods of single-crystal thin-films of YAG for acoustical and optical applications is presented. It is shown that the thermal exfoliation is the preferred method for YAG. After the thermal exfoliation, the films are subject to additional thermal cycle to anneal the films. This process high-temperature annealing is introduced to promote relaxation of film by eliminating residual strain and increasing the films' radius of curvature, both attributed to the ion-implantation process. Thus, detailed description of the post-exfoliation process is presented. The mechanical quality of the films is investigated with specific attention to the annealing behavior. Finally, the fabrication process and optical characterization of single-crystal thin-films of diamond is described. The work on diamond is focused on developing a parallel fabrication process for high-optical-quality single-crystal diamond membranes for quantum information processing (QIP) applications. The diamond membranes, with thickness as small as 200 nm and over 100 μm on their side, exhibit nitrogen-vacancy emission spectra including the zero phonon line (ZPL) peak of negatively charged centers. The films are patterned and sliced in parallel from a single-crystal diamond sample. The compatibility of the membrane with planar optical devices is demonstrated by the formation of two-dimensional photonic crystal patterns in 200 nm films. The films are produced by a combination of thermal annealing, chemical etching and oxygen plasma. Analysis of the films quality and optimization of the exfoliation process is evaluated by a verity of experimental techniques including: Atomic force microscope (AFM), optical microscopy, scanning electron microscopy (SEM), Raman and fluorescence spectroscopy, optical profilometry and nanoindentation

Low-voltage nanodomain writing in He-implanted lithium niobate crystals

A scanning force microscope tip is used to write ferroelectric domains in He-implanted single-crystal lithium niobate and subsequently probe them by piezoresponse force microscopy. Investigation of cross-sections of the samples showed that the buried implanted layer, $\sim 1$\,\textmu m below the surface, is non-ferroelectric and can thus act as a barrier to domain growth. This barrier enabled stable surface domains of $< 1$\,\textmu m size to be written in 500\,\textmu m-thick crystal substrates with voltage pulses of only 10\,V applied to the tip

Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

The negatively charged nitrogen vacancy (NV⁻) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV⁻ state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.United States. Army Research Office (W911NF-12-1-0594)United States. National Institutes of Health (1R01NS087950)United States. Defense Advanced Research Projects Agency (D14PC00121)United States. Defense Advanced Research Projects Agency (HR0011-14-C-0018)United States. National Institutes of Health (1R43MH102942-01)National Science Foundation (U.S.) (1122374

Fabrication of Triangular Nanobeam Waveguide Networks in Bulk diamond Using Single-Crystal Silicon Hard Masks

A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q=2.51x10^6) photonic crystal cavities with low mode volume (Vm=1.062x({\lambda}/n)^3), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q=3x103.Comment: This article will be published in Applied Physics Letter

Top-Down, Scalable Fabrication of High Purity Fluorescent Nanodiamonds

We demonstrate a fabrication technique for high volume production of high quality nanocrystals from bulk chemical vapor deposition diamond. Ramsey and Spin-Echo measurements confirm the long spin coherence of nitrogen vacancy centers in these nanocrystals

Wide-Field Multispectral Super-Resolution Imaging Using Spin-Dependent Fluorescence in Nanodiamonds

Recent advances in fluorescence microscopy have enabled spatial resolution below the diffraction limit by localizing multiple temporally or spectrally distinguishable fluorophores. Here, we introduce a super-resolution technique that <i>deterministically</i> controls the brightness of uniquely addressable, photostable emitters. We modulate the fluorescence brightness of negatively charged nitrogen-vacancy (NV^–) centers in nanodiamonds through magnetic resonance techniques. Using a CCD camera, this “deterministic emitter switch microscopy” (DESM) technique enables super-resolution imaging with localization down to 12 nm across a 35 × 35 μm² area. DESM is particularly well suited for biological applications such as multispectral particle tracking since fluorescent nanodiamonds are not only cytocompatible but also nonbleaching and bright. We observe fluorescence count rates exceeding 1.5 × 10⁶ photons per second from single NV^– centers at saturation. When combined with emerging NV^–-based techniques for sensing magnetic and electric fields, DESM opens the door to rapid, super-resolution imaging for tracking and sensing applications in the life and physical sciences

Nanoscale Engineering of Closely-Spaced Electronic Spins in Diamond

Numerous theoretical protocols have been developed for quantum information processing with dipole-coupled solid-state spins. Nitrogen vacancy (NV) centers in diamond have many of the desired properties, but a central challenge has been the positioning of NV centers at the nanometer scale that would allow for efficient and consistent dipolar couplings. Here we demonstrate a method for chip-scale fabrication of arrays of single NV centers with record spatial localization of about 10 nm in all three dimensions and controllable inter-NV spacing as small as 40 nm, which approaches the length scale of strong dipolar coupling. Our approach uses masked implantation of nitrogen through nanoapertures in a thin gold film, patterned via electron-beam lithography and dry etching. We verified the position and spin properties of the resulting NVs through wide-field super-resolution optically detected magnetic resonance imaging