Biomedical Engineering Reference
In-Depth Information
Fig. 2.16.
The measurement arrangement for ultrasound by LIB. The
z
-axis was set
along the laser beam and the other axes were normal to
z
. Ultrasound was received
with a needle hydrophone, amplified, and stored in a digital storage oscilloscope
(DSO)
5
4
3
2
1
0
-1
-2
-3
-4
0
10
20
30
40
50
t[ sec]
μ
Fig. 2.17.
The waveform of the ultrasound by LIB, which has a large peak at 30
μ
s
and small ones at 30-50
s. The former is the wave received by LIB directly, while
the latter is reflected at the walls of a water bath or the water surface
μ
Using the same measurement system as seen in Fig. 2.16, we investigated
the directivity of the ultrasound generated by LIB. In this experiment, the
origin of the coordinates was set at the LIB point. The measurement points
were varied from
−
70 to 70 mm in the
x
direction at a constant step of 10 mm,
