Figure 2: Cavity-enhanced absorption and Raman imaging.
From: Cavity-enhanced Raman microscopy of individual carbon nanotubes
(a,b) Acquisition of a Raman spectrum by tuning a cavity resonance across a spectral range around the G± band and combining individual exposures. (b) Each horizontal line corresponds to an individual spectrum acquired for a particular cavity length. The strong line shows the tuning of the fundamental mode, the second weaker line corresponds to the first higher transverse mode of the cavity. (a) Spectrum obtained by taking the maximum of all exposures for each spectral position. (c) Broadband spectrum covering the G± and G′ band at 1,590 cm−1 and 2,650 cm−1 respectively. The differently shaded areas depict the range which individual longitudinal cavity modes cover at a mirror separation of 14.3 μm. (d) Scanning-cavity microscopy of the extinction cross-section σext of isolated CNTs. (e,f) Raman hyperspectral imaging of the same area showing selectively the strength of the G′ and the G± band, respectively. Scale bars, 20 μm.
