EnergyMax Pyroelectric Sensor Selection Guide

Use the following charts to help choose the right EnergyMax sensor for your particular laser. The first chart shows the energy range for each of the sensors.

The next chart illustrates the spectral range of each sensor. This characteristic is coating dependent, therefore sensors with diffusers have a narrower spectral range than the same sensor operated without a diffuser. Each sensor contains spectral compensation unique to that serial number based upon spectral scans performed on each sensor disc (and each optic if the sensor has a diffuser). This provides for greater measurement accuracy for wavelengths that differ from the optical calibration wavelength.

The next chart shows the spectral absorption of each sensor coating. Note that all EnergyMax sensors incorporate a diffuse coating to minimise specular reflections, which in turn eliminates spurious beams that can re-enter the laser cavity. All EnergyMax sensors include the convenience of onboard electronics that contain built-in wavelength compensation factors. When using the sensor with the LabMax TOP, FieldMax II TOP or FieldMax II P meters, you simply enter the wavelength of the laser being measured into the meter and the sensor will be automatically calibrated for that wavelength.

The next chart summarises the maximum average power that each sensor can be exposed to. These power levels are achieved through the use of active temperature compensation circuitry combined with enhanced thermal management techniques. Maximum average power is wavelength dependent because the absorption changes with wavelength. Reference the spectral absorption chart above for use at other wavelength; maximum average power is inversely proportional to the spectral absorption (a doubling of absorption means a halving of the maximum power loading). The 25mm and 50mm aperture sensors can accept optional heat sinks that are user installable by mounting on to the back of the sensor. These heat sinks expand the average power handling capability as outlined below.

Notes:

1. 50mm sensors are compatible with the large heat sink
2. 25mm sensors are compatible with the small and medium heat sinks
3. 10mm sensors are not available with heat sinks
4. Average power ratings are based upon testing at the listed wavelength

The next chart details the range of pulse repetition frequencies that EnergyMax sensors can be used with. Pyroelectric sensors can measure lasers at high repetition rates. The maximum repetition rate is primarily dependent upon the thermal resistance of the coating and the maximum pulse width the sensor is designed to measure. These sensors can also measure individual pulses, so a minimum repetition rate of “1” in the table below means that the sensor will respond to lasers with repetition rates of 1Hz or less. Refer to the specification summary table on the main EnergyMax page for maximum laser pulse width limitations for each sensor.

It is important to ensure the laser beam will not damage the sensor coating prior to use. Damage threshold is wavelength dependent, and maximum fluence thresholds are listed for common laser wavelengths in the table below. At other wavelengths it is typically safe to interpolate between the listed values. A test slide of the particular sensor coating is included with each EnergyMax sensor purchased that helps to protect your sensor when measuring unknown beams. The test slide is inserted into the beam and then examined for damage. These test slides are coated with the same absorbing coating as the pyroelectric sensors. If coating damage is visible, then attenuation is required before measuring the beam. Additional test slides are available for purchase.

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