Luminescence Microscopy of Single Quantum Dot Pairs with Nanometer Spatial Resolution

Microscopic Insight into the Inhomogeneous Broadening of Zero-Phonon Lines of GeV– Color Centers in Chemical Vapor Deposition Diamond Films Synthesized from Gaseous Germane

“…Also, with broadband excitation the probability of exciting several centers simultaneously increases, which makes it more difficult to recognize and separate their images. 69 To this end, the second experimental setup 70,71 was employed which was equipped with a stabilized tunable single-mode dye laser (Coherent CR599-21) with a line width of ∼2 MHz and continuous tuning range up to 75 GHz. The laser frequency was scanned in discrete steps over a defined interval in the range 602.2−602.7 nm (usually 500−2000 steps within 5−30 GHz with 100 ms exposure time for each step) with recording of the CCD frame after each step.…”

“…The first setup was used for recording broad overview PLE spectra, yet, the spectral resolution of the laser (8–16 GHz) was not sufficient for measuring the homogeneous line width of the ZPLs of GeV – centers at cryogenic temperatures. Also, with broadband excitation the probability of exciting several centers simultaneously increases, which makes it more difficult to recognize and separate their images …”

Quantum Dots for Improved Single-Molecule Localization Microscopy

“…Recent studies have validated the applications of upconverting nanoparticles, , nitrogen-vacancy color centers in nanodiamonds, , and aggregation-induced emission , for patterned illumination methods such as stimulated emission depletion. For localization-based methods, colloidal semiconductor quantum dots (QDs), as well as similar carbon- and polymer-based nanodots, are expected to achieve similar enhancements in resolution. ,,− Like the aforementioned nanoparticles, QDs are extremely photostable and very bright emitters, allowing for the observance of fluorescence from individual QDs with a high signal-to-noise ratio (SNR) from tens of minutes to hours. ,− Also, broad absorption spectra coupled with narrow emission spectra allow for simpler spectral multiplexing using a single excitation source. ,, Additionally, QDs naturally exhibit inherent fluorescence blinking, which eliminates the need for multiple photoactivation lasers or oxygen-reducing buffers in order to enable the fluorescence intensity blinking required for super-resolution imaging applications . QDs have also been proven to be viable fluorescent labels in many biological imaging applications including cancer cell detection, tumor drug delivery, cellular sensing, and molecular tracking. − …”

Steady-state photoluminescence and nanoscopy of two near-identical emitters with dipole-dipole coupling

“…At the same time, more novel techniques to measure small separations with a fine accuracy are under way. For example, a new experimental method for direct measurements of the separation between two semiconductor colloidal quantum dots (down to 20 − 10 nm) from fluorescent images was recently described in [21]. The growing ability to observe the relationship between the distance and changes in absorption and emission requires a better theoretical description of small cooperative ensembles.…”