arXiv subjects

Tamiko Masuda

Publications and source records attributed to Tamiko Masuda.

3 recordsLinked to original sources

arXiv2023

Fiber-taper collected emission from NV centers in high-$Q/V$ diamond microdisks

Fiber-coupled microdisks are a promising platform for enhancing the spontaneous emission from color centers in diamond. The measured cavity-enhanced emission from the microdisk is governed by the effective volume ($V$) of each cavity mode, the cavity quality factor ($Q$), and the coupling between the microdisk and the fiber. Here we observe photoluminescence from an ensemble of nitrogen-vacancy centers into high $Q/V$ microdisk modes, which when combined with coherent spectroscopy of the microdisk modes, allows us to elucidate the relative contributions of these factors. The broad emission spectrum acts as an internal light source facilitating mode identification over several cavity free spectral ranges. Analysis of the fiber-taper collected microdisk emission reveals spectral filtering both by the cavity and the fiber-taper, the latter of which we find preferentially couples to higher-order microdisk modes. Coherent mode spectroscopy is used to measure $Q\sim 1\times10^{5}$ -- the highest reported values for diamond microcavities operating at visible wavelengths. With realistic optimization of the microdisk dimensions, we predict that Purcell factors of $\sim 50$ are within reach.

physics.optics↗

arXiv2019

Influence of nanostructuring on silicon vacancy center spins in diamond pillars

Color centers in diamond micro and nano structures are under investigation for a plethora of applications. However, obtaining high quality color centers in small structures is challenging, and little is known about how properties such as spin population lifetimes change during the transition from bulk to micro and nano structures. In this manuscript, we studied various ways to prepare diamond samples containing silicon vacancy centers and measured how population lifetimes of orbital states change in pillars as we varied their dimensions from approximately 1 $μ$m to 120 nm. We also researched the influence of the properties of the diamond substrate and the implantation and annealing methods on the silicon vacancy inhomogeneous linewidth and orbital lifetime. Our measurements show that nominally identical diamond samples can display significantly distinct inhomogeneous broadening. We observed weak indications that restricted vibrational modes in small structures may extend population lifetimes. However, imperfections in the crystal lattice or surface damage caused by etching reduce population lifetimes, especially in the smallest structures.

quant-ph↗

arXiv2016

Single-crystal diamond low-dissipation cavity optomechanics

Single-crystal diamond cavity optomechanical devices are a promising example of a hybrid quantum system: by coupling mechanical resonances to both light and electron spins, they can enable new ways for photons to control solid state qubits. However, realizing cavity optomechanical devices from high quality diamond chips has been an outstanding challenge. Here we demonstrate single-crystal diamond cavity optomechanical devices that can enable photon-phonon-spin coupling. Cavity optomechanical coupling to $2\,\text{GHz}$ frequency ($f_\text{m}$) mechanical resonances is observed. In room temperature ambient conditions, these resonances have a record combination of low dissipation (mechanical quality factor, $Q_\text{m} > 9000$) and high frequency, with $Q_\text{m}\cdot f_\text{m} \sim 1.9\times10^{13}$ sufficient for room temperature single phonon coherence. The system exhibits high optical quality factor ($Q_\text{o} > 10^4$) resonances at infrared and visible wavelengths, is nearly sideband resolved, and exhibits optomechanical cooperativity $C\sim 3$. The devices' potential for optomechanical control of diamond electron spins is demonstrated through radiation pressure excitation of mechanical self-oscillations whose 31 pm amplitude is predicted to provide 0.6 MHz coupling rates to diamond nitrogen vacancy center ground state transitions (6 Hz / phonon), and $\sim10^5$ stronger coupling rates to excited state transitions.

quant-ph↗