eoProbe: the probe to measure the E-field (EMF)

It measures one component of the electric field vector based on the electro-optic technology. This Ultra-Wide Band sensor allows accurate measurements in almost any location and environment (air, liquids, gases, vacuum) under harsh conditions.
Each eoProbe is delivered with a Routine Test report valid for 2 years.
This probe must be used with the eoSense converter.

12 EMF probe versions to match your needs

Reference Environment Sensitivity – Bandwidth Type
ET5-air Low permittivity (Air / oils) 250 mV/m – 30 Hz … 10 GHz Transverse
ET1-air Low permittivity (Air / oils) 500 mV/m – 30 Hz … 50 GHz Transverse
EL5-air Low permittivity (Air / oils) 50 mV/m – 30 Hz … 10 GHz Longitudinal
EL1-air Low permittivity (Air / oils) 200 mV/m – 30 Hz … 50 GHz Longitudinal
ET5-vac Low permittivity (vacuum) 250 mV/m – 30 Hz … 10 GHz Transverse
ET1-vac Low permittivity (vacuum) 500 mV/m – 30 Hz … 50 GHz Transverse
EL5-vac Low permittivity (vacuum) 50 mV/m – 30 Hz … 10 GHz Longitudinal
EL1-vac Low permittivity (vacuum) 200 mV/m – 30 Hz … 50 GHz Longitudinal
ET5-bio High permittivity
(water based liquids)
50 mV/m – 30 kHz … 1 GHz Transverse
ET1-bio High permittivity
(water based liquids)
200 mV/m – 30 kHz … 1 GHz Transverse
EL5-bio High permittivity
(water based liquids)
50 mV/m – 30 kHz … 1 GHz Longitudinal
EL1-bio High permittivity
(water based liquids)
200 mV/m – 30 kHz … 1 GHz Longitudinal

Main specifications

Characteristics Values
Sensitivity and bandwidth See above eoProbe versions table
Dynamic of measurement ≥ 130 dB.√Hz
Selectivity ≥ 50 dB
Spatial resolution ≤ 1 mm
Operating temperature 0 … +50 °C (32 … 122 °F)
Operating pressure  0 … 2030 hPa (0 … 29.4 PSI)
Max E-field without damage  10 MV/m
Max B-field without damage  4.7 Tesla
 Ingress protection rating  IP 67 (sensor only)
 Chemical compatibility of gases  Air, nitrogen, plasmas, SF6
 Chemical compatibility of liquids  Water, oils, alcohols, biological liquids
 Probe cleaning  Clean lightly moistened with isotropilic alcohol
Fibre optic diameter  2.8 mm (see data sheet for vacuum)
 Optic fibre minimum bend radius  40 mm (see data sheet for vacuum)

Download PDF data sheet

eoProbe data sheet

A flexible design

The eoProbe is manufactured with 5 meters of fibre optic length. You need more distance? A fibre optic extension accessory is available up to a total of 100 meters.

Not sure about the performances?

You are not sure about the performances of our system. No worries! Please check our services page and discover the various possibilities that Kapteos may propose to you.

Page of Kapteos services

You could also simulate the performances of our various systems inside your applications Thanks to our online Simulation Software Tool.

Simulation Software page

Main advantages

Near and far field

Vector near and far E-field measurement

Thanks to its high performances, the eoProbes can measure both near and far E-field.

Non perturbative measurement

No impact on the measured E-field

The probe construction does not include any metal part, hence the measured electric field is not perturbated. The eoProbe measures the exact E-field.

Insulated EMF probe more than 600 kV

Fully insulated probe

Without any metal elements inside the probe, eoProbe is fully insulated. It is then possible to measure E-field under very high potential (several kV).

Basic frequency curve


Thanks to its technology based on Pockels effect, the probe can measure E-fields from 10 Hz up to 50 GHz with an excellent linearity.

Submillimetric compact design

High resolution and compactness

Its high compactness and sub-millimetric spatial resolution allows to measure very precisely the E-field.

Measurement indoor and outdoor

Outdoor operation

Even under outdoor conditions (0 to 50°C for the probe), E-field measurement can be performed with good results.

Accessories for the eoProbe

Kapteos Electric Filed Probe holder eoPod

eoPod for eoProbe sensors

This accessory allows via its articulated arm to maintain the probe  on a specific location. It is fully dielectric hence can be used near E-field sources. 2 versions are available: one for air and vacuum probes and one for bio probes.

eoLink fibre optic extension

Fibre optic extension

The fibre optic extension is inserted between the eoSense converter and an eoProbe sensor to increase the distance up to a maximum of 100 meters. A rugged version for outdoor usage is available in standard.

eoCal Electric Field Probe Calibration

eoCal for electric field probe calibration

For a very accurate measurement inside liquid medium or air, eoCal is an easy and fast calibration accessory of your electric field probes.

eoVac vacuum feed through for electric field probe air type

eoVac for air eoProbe type under vacuum

For using an air probe type under low vacuum conditions (> 1 mbar). Designed for KF50 flanges down to KF16.