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4 Mathematical Models of the Interaction of Laser Radiation with Turbid Media
method of statistical weights. In [7], the absolute average flow rate of a biological
fluid in microcapillaries and the flow direction were determined experimentally.
In this study, we will use an electrodynamic model, which makes it possible.
1. to vary such parameters of a biological structure as the real and imaginary parts
of the refractive index of the blood, epidermis, upper dermis, and lower dermis;
2. to ascertain dependences between these parameters and the biological properties
of blood irradiated by a laser beam;
3. to determine the rate of the blood flow in the capillary bed. This allows one to
diagnose diseases whose manifestation is related with a decrease in the effective
diameter of capillaries and with changes in the biophysical properties of blood.
Chapter is based on the result of the [8].
The biological tissue is represented in the form of layers with different optical
characteristics (the epidermis, upper dermis, blood, and lower dermis), which are
irradiated by a laser beam. The system of blood vessels is located in the upper layer
of the dermis.
4.3 Reflection of a Plane Wave from a Layer with a Slowly
Varying Thickness
In this section, we will find the coefficient of reflection from a layer with a slowly
varying thickness.
Fig. 4.4 Schematic diagram
of a model biological
medium
Z
X
n1
Y
2, (
1
n
2
2
3
3
4
3,
4,
5,
5