Stimulated Emission Depletion Microscopy with Diamond Silicon Vacancy Centers

Abstract

The spatial resolution and fluorescence signal amplitude in stimulated emission depletion (STED) microscopy is limited by the photostability of available fluorophores. Here, we show that negativelycharged silicon vacancy (SiV) centers in diamond are promising fluorophores for STED microscopy, owing to their photostable, near-infrared emission and favorable photophysical properties. A homebuilt pulsed STED microscope was used to image shallow implanted SiV centers in bulk diamond at room temperature. The SiV stimulated emission cross section for 765-800 nm light is found to be (4.0 ± 0.3)×10 −17 cm 2 , which is approximately 2-4 times larger than that of the negatively-charged diamond nitrogen vacancy center and approaches that of commonly-used organic dye molecules. We performed STED microscopy on isolated SiV centers and observed a lateral full-width-at-halfmaximum 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. We show that the present microscope can resolve SiV centers separated by 150 nm that cannot be resolved by confocal microscopy.

Stimulated Emission Depletion Microscopy with Color Centers in Hexagonal Boron Nitride

“…). These cross-sections compare favourably with centers in diamond 16,18 and organic dye molecules 4,5 and demonstrate the clear potential for hBN color centers to find application in STED microscopy. The relatively large variation in the STED cross-section can be attributed to variations in the efficiency of the optical phonon-assisted depletion from defect to defect.…”

“…15,16 Furthermore, the photoluminescence intensity is low and spans a large spectral range due to phonon assisted emission, and photocharging can result in blinking, particularly in nano-diamonds with diameters < 10 nm. 17 In recent work, negatively charged silicon vacancies (SiV) have been proposed as an alternative, 18 offering the favourable properties of diamond, but with a larger STED cross-section (4 × 10 −17 cm −2 ). These impressive results with diamond raise the question of whether color centers in other wide bandgap semiconductors have potential for STED microscopy.…”

Near-field radio-frequency imaging by spin-locking with a nitrogen-vacancy spin sensor

“…The spatial resolution is ultimately limited by the distance of the implanted NV center layer from the surface of the diamond chip of about 10 nm, and is practically limited by the resolution of an optical microscope to be used and may be enhanced by applying super-resolution imaging such as stochastic optical reconstruction microscopy 26 and stimulated emission depletion microscopy 27 . In our method, the number of pixels of the image is not limited by the number of electric wiring for sensors as used in many existing methods.…”

Carbon Nanomaterials: Synthesis, Functionalization and Sensing Applications

“…This opened the possibility to use fluorescent NDs in high resolution microscopy where photostability is highly required. For example SiV defects were utilized to perform high resolution stimulated emission depletion microscopy with a resolution better than 150 nm [255]. In another work fluorescent nanodiamonds (FND) were used in correlative microscopy as dual-contrast probes [256].…”