LaserPoint Plus2 Instruction Manual page 12

Typically this tool is particularly useful to normalise a measurement or when the measurement is taken out of a
complex optical systems where, for instance, a beam splitter is used to extract a fraction of an optical signal; in
most cases the beam splitter has two output optical ports with significantly different splitting ratios to allow the
laser beam to exit the main port of this component almost unaltered and enabling the monitoring of the beam
power or energy by measuring the small fraction of the beam at the monitoring port output.
If the power meter is connected to a sensor head placed at the monitoring port, a gain factor can be set to take into
account the device optical splitting ratio by adjusting Gain factor and make the instrument show a power reading
as though the sensor head were placed in front of the original laser beam. The selection of Gain option need the
input of a number by means of the digital keyboard popping up upon touching the small box at the right of this
parameter writing; the parameter input is accomplished in a similar way as described in the previous paragraph 10
for the measurement wavelength selection.
The Average factor is a useful tool when the signal is low and noisy and allows a cleaner signal read out; its
settable value represents the time period during which the head signal averaging occurs.
Average value can be set from 0.1 sec to 99 sec and when a value greater than zero has been entered a yellow
frame borders Measure key and an "Avg." notice appears just in the right side of the display segment f) ( see Fig.
4).
Measure function key allows also to set and take into account the laser beam Shape and dimensions; this feature
is particularly useful when irradiance and/or fluence are important information to the user like in the case of
certain medical protocols that have to guarantee the deposit a certain dose of photonic power or energy per unit
surface.
The measurement of Irradiance (power density) or Fluence (energy density) requires the selection of a laser beam
Shape and the definition of the beam area. This selection has to be done among the following options: none,
circular, rectangular.
If none option is being selected, the integral beam power or energy will be measured and the display keeps on
showing the measurement power or energy values in W or J or their sub-units.
If the circular beam shape is being selected the Radius box is activated and upon touching it the beam radius in
millimeters can be entered after touching the relative box by the already described digital keyboard.
If the rectangular beam shape is being selected the Width x Height boxes are activated and their relative
dimensions in millimeters have to be entered by the usual digital keyboard.
In both cases of circular and rectangular beam shape selection, the Irradiance measurement values are expressed
in W/cm2 units or sub-units and the Fluence measurement values are expressed in J/cm2 units or sub-units. The
beam area in square centimeters is calculated by the instrument and shown in the box aside the Area writing.
To de-activate Irradiance/Fluence mode, select none for Shape in the "Measure Settings" window.
The last two parameters reported at the bottom of "Measure Settings" window are DAC and Last Calib.
DAC stands for the analogue output sensitivity and is stored in the head intelligent connector memory. Its value
is factory set and is expressed in mV/W. In certain cases it might be convenient to expand the sensitivity of the
analogue output signal and this coefficient can be changed by the user by means of the digital keyboard popping
up after touching the small box aside DAC writing.
Last Calib. Indicates the instrument last calibration date and is for information only.
Note: in the case Energy Mode has been selected, "Measure Settings" window shows some parameters that are
specific of pulse energy measurements, hence further information pertaining to energy measurement settings is
reported in Mode key chapter 12.
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LaserPoint s.r.l.- Plus2 Power & Energy Meter Instruction Manual - All Rights Reserved