Ophir Optronics Ltd QSR Manuel D’Utilisation

This chapter provides an overview of pyroelectric and PD10 heads and 
instructions for taking measurements with these heads. Topics include: 

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Ophir pyroelectric heads measure both frequency and energy of pulsed lasers. 
When a pulsed heat source, such as a laser, is directed at the detector, a 
temperature gradient is created across the pyroelectric crystal mounted in the 
head. An electric charge is produced, which is proportional to the energy 
absorbed. The detector head has sophisticated circuitry unique to Ophir 
(patented) that determines the baseline before the pulse is received, measures the 
voltage after a pre-determined interval, amplifies it, and holds it for a pre-
determined time. 

Due to this innovative circuitry, Ophir pyroelectric heads can measure very long 
pulses as well as short ones; low energies as well as high energies. They can also 
measure at higher repetition rates than was possible before. 

The device to which the head is connected converts this signal to a digital value 
and indicates the energy received by the head, as well as the frequency at which 
the laser is pulsing. Using the energy and frequency information, the StarLab 
application is also able to display average power. 

Ophir PD10 heads differ from pyroelectric heads in that their detector is a 
photodiode instead of a pyroelectric crystal. They use a similar circuit to the 
pyroelectric heads and offer similar functionality. Therefore, throughout this 
guide, they are included in the generic term "pyroelectric" when referring to 
software and control functions, even when this is not stated explicitly.