Coherent Microscopy and Optical Coherence Tomography for Biomedical Applications - Bioanalysis Advanced Materials Methods and Devices - page 120

Fig. 8.17 TF of a
polychromatic CSI system

Measured
Frequencies

k z

k x

Fig. 8.18 PSF of a CSI
system (positive real part
shown)

where the function A k ðÞ is defined by the convolution,

ð þ1

G NA kðÞG NA k

k 0 d 3 k 0 A k ðÞ¼ ð Þ (8.11)

1

For the sake of comparison, the PSF has been computed in Fig. 8.18 for a CSI
with NA 600 nm and a

Gaussian spectral distribution with bandwidth of 100 nm (FWHH@1/ e 2 ). It can be
seen that the lateral dimensions of the PSF are approximately half that of the
coherent microscope and the OCT system (Fig. 8.7 and Fig. 8.13 ) while the axial
extent is slightly reduced.
Interestingly, the PSF of a laser confocal microscope (configuration shown
in Fig. 8.19 ) is directly related to that of CSI [ 21 ]. In confocal microscopy,
however, the detection process is not usually coherent (i.e., not interferometric)
and consequently the PSF takes the form of the envelope of the PSF of a quasi-
monochromatic CSI of the same NA.

¼ 0.55 operating with the same mean wavelength of l ¼