Coherent Raman Scattering Microscopy - Emerging Raman Applications and Techniques in Biomedical and Pharmaceutical Fields - page 117

A B

F-CARS

F-CARS xy -image F-CARS

detector

k 0

L
F k P k AS

FWHM 0.34 m

0 1 2 3

x ( m)

AS

k P k S

C

F-CARS xz -image

Obj z

0.0

FWHM
1.18 m

y 0.5

sample

1.0

x

1.5

2.0

Obj

2.5

3.0

3.5

BS

4.0

p

0 500 1000

E-CARS

signal (cts)

S

AS

k 4 n

D

E-CARS xy -image

AS

F

L k P k AS

FWHM
0.34 m

E-CARS
detector

k P k S

0 1 2 3

x ( m)

Fig. 6.3. A Schematic configuration of forward- and epi-detected CARS (F- and
E-CARS) microscopy with collinear, co-propagating pump and Stokes beams. The
corresponding wave vector mismatch and diagrams along the optical axis z are in-
dicated (BS: dichroic beam splitter; Obj: objective lens; F: filter; L: lens). B and
D F- and E-CARS x - y images of a 0 . 5-μm polystyrene sphere embedded in wa-
ter, recorded at a Raman shift of 1595 cm − 1 with pump- and Stokes wavelengths
at 800 and 917 nm, respectively. The lateral intensity profiles along the lines indi-
cated by the arrows reveal a typical lateral resolution of 340 nm (FWHM). C F-
CARS x - z image of an interface between a cover glass and immersion oil, recorded
with pump and Stokes pulses at 717 and 900 nm (Raman shift: 2840 cm − 1 ), respec-
tively. The axial edge profile along z together with its smoothed first derivative
(solid line) reveals a typical longitudinal resolution in CARS microscopy of 1 . 2 μ
m(FWHM)