5 PICOSCALE HARDWARE
Table 5.7: Main performance data of DAC1
Parameter
Typical Value
Unit
Full-scale output voltage
±
10
V
Sample-rate
10
MS /s
Resolution
12
Bit
Bandwidth
f
1
dB
2-2.5
MHz
Table 5.8: Main performance data of DAC2-5
Parameter
Typical Value
Unit
Full-scale output voltage
±
10
V
Sample-rate
200
kS /s
Resolution
16
Bit
Bandwidth
f
1
dB
130-170
kHz
5.4 Sensor heads
Figure 5.8: Selection of
PICO
SCALE
sensor heads: (A)
PS-SH-C01, (B) PS-SH-F01, (C) PS-SH-C03, (D)
PS-SH-C02.
The
PICO
SCALE
interferometer sensor heads are based on an optical
fi
ber, a
fi
ber ferrule, a colli-
mator and a beam splitter cube. The optical
fi
ber (single mode, minimum bending radius
10 mm
)
is terminated with a 8
◦
ferrule. The angle is introduced to suppress parasitic interferences. A gra-
dient index (GR
I
N) lens (also with 8
◦
angle) is glued to the ferrule and used to collimate the laser
beam. The key component is the beam splitter cube. The beam is split into two parts. One part is
guided to the reference mirror that is coated to one of the surfaces of the cube. The other part is
guided to the target. Given proper alignment, the probe beam interferes with the reference beam
in the beam splitter cube. The interfering light is guided through the optical
fi
ber back into the
PICO
SCALE
Controller, where it is detected by a photo detector and the interference pattern is
evaluated.
40
PicoScale User Manual
