Full text loading...
Scheme of the experimental setup. A CARS setup is used which realizes a two-color CARS scheme. A narrowband pump (3–4 nm) and a broadband (ca. 10 nm) Stokes are used to excite Raman bands in the C-H (ca. 2880–2960 cm−1) or the C-D (ca. 2260–2350 cm−1) stretching region. The Stokes is shaped by an LC-SLM, which modulates the amplitude and phase of the spectrum. Pump and Stokes are temporally synchronized by a delay stage. After recombining pump and Stokes pulses by a longpass-filter, the beams are directed into a laser-scanning microscope for CARS microscopy. λ/2: half-wave plate; G: gratings with 1800 grooves/mm (Zeiss); f: focal length (80 mm) of the cylindrical lenses in the 4f-setup; L1: lens with focal length 200 mm; L2: lens with focal length 50 mm; L3: lens with focal length 750 mm; Spec.: Spectrometer (Optical spectrum analyser from Andor); Δτ: delay stage.
(a) Raman spectra of toluene and perdeuterated toluene. (b) Raman spectra of DMSO and toluene in the C-H stretching region.
(a) Optimization curve of CD-toluene vs. CH-toluene (red) and vice versa (blue). (b) Optimized CARS images. Left: The CARS intensity of CD-toluene is optimized (right channel); Middle: Reference; Right: CARS image with optimized contrast for CH-toluene; The CARS intensity profiles taken along the white arrows are depicted underneath. (c) Spectra of the shaped Stokes pulses (blue and red, respectively) and the reference Stokes pulse (black).
(a) Optimization curves of DMSO vs. toluene (red) and vice versa (blue) after dividing the best value of the generation by the value of the reference individual. (b) Optimized CARS images. Left image: DMSO versus toluene is highlighted. Middle: toluene versus DMSO is optimized. Right image: reference (full transmission). The intensity profiles taken along the drawn white arrow are depicted below the images. (c) Spectra of the shaped Stokes pulses (red and blue, respectively) and the reference Stokes pulse (black).
Article metrics loading...