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.
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.