Current mode operation provides a higher responsivity with a low offset with a low temperature dependence. In current mode an op-amp is used in conjunction with a negative feedback loop. Current mode also provides a low electrical time constant and faster recovery times, allowing customers to use current mode devices at much higher frequencies than voltage mode devices with less signal loss.
Voltage mode vs current mode
Both voltage mode and current mode pyroelectric detectors are manufactured by LASER COMPONENTS. Voltage mode detectors are simple JFET source follower based devices converting a high impedance input to a low impedance output. Voltage mode operation does have the advantage of being capable of giving the highest D* (at 10Hz) with a relatively simple circuit with very flexible amplification. Voltage mode devices are not without their failures; producing relatively low signal and a strongly temperature dependent offset.