Cartoon representation of the laser focus and spatial modulation of the sample in the SCSMS experiment.
Schematic of the experimental setup. The output of the laser is passed through a polarizing beam splitter. The two portions are then sent through different AOTFs where they can be tuned from 420 to 700 (visible) and 600 to 1100 nm (near infrared, NIR). The NIR beam's polarization is then rotated 90° with a broadband λ/2 waveplate. At this point, the beams are made collinear, expanded, and split into reference (70%) and signal (30%) channels which are then used to obtain autobalanced detection of the modulated signal.
Large area false-color extinction maps of (a) d ∼ 20 nm and (b) d ∼ 40 nm Au NPs drop cast onto borosilicate coverslips. Double-lobed bright regions correspond to single Au NPs. In (a), the pixel dwell time is 100 ms and the pixel step size is 250 nm, whereas (b) has a 30 ms pixel dwell time and a step size of 100 nm. Absolute extinction spectra of single (c) d ∼ 40 nm and (d) d ∼ 13 nm Au NPs (blue circles). Insets show TEM micrographs where scale bars are (c) 40 nm and (d) 15 nm. (e) Average σ ext -values at λ exc = 530 nm for different NP diameters (red triangles). Standard deviations in σ ext -values are reported, where the number of NPs measured for each size is N = 10. Average NP diameters were measured from N = 55 NPs using TEM micrographs (standard deviations reported).
(a) Extinction spectrum of a single d ∼ 8 nm Au NP (blue open circles). Inset: Corresponding two-dimensional false-color extinction map of the Au NP at λ exc = 530 nm, where the legend is in units of σ ext ×10−13 cm2. (b) Representative extinction spectra of different-sized Au NPs. Inset: Average SNRs for single Au NP extinction spectra plotted against NP volume (red open circles).
Comparison of the experimental noise (open green circles) and the shot-noise limit (open red triangles). The black solid line corresponds to a least squares fit of V noise using Eq. (7) . Inset: Experimental V noise plotted against V DC on a linear scale.
(a) Extinction spectra of two individual d ∼ 1 nm [(8,3), top; (6,5), bottom] SWCNTs (open circles) along with their corresponding Lorentzian fits (black dashed lines). (b) Extinction spectrum of a d ∼ 8 nm (open red circles) and a d ∼ 5 nm (open green circles) CdSe NW. The dashed black lines correspond to a sum-of-Gaussians fit to the data. Individual Gaussians are shown as dotted red lines.
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