These are classical photoconductive infrared detectors. PbS has a relatively high detectivity; PbSe extends the responsivity farther into the infrared. As with all infrared detectors, they benefit significantly from operating at lower temperatures. PbS and PbSe detectors are subject to 1/f noise due to bias current. We offer them for AC operation only.
Fig. 1 NEP values of PbS and PbSe detectors.
Fig. 2 Relative responsivities of PbS and PbSe detectors.
Stability
Good stability of response is obtained with the TE cooled and stabilized detectors. Room temperature units show the usual drift with changing ambient conditions. Both PbS and PbSe are subject to a change of responsivity when exposed to blue to UV light. They usually recover but it may take days of dark storage before full recovery occurs. These detectors require a bias voltage; a 100 V bias supply is built into the detector housings.
Measurable Power
The NEP plot (Fig. 1) shows the typical minimum measurable power levels of our PbS and PbSe detectors. You will need an attenuator to measure power levels above approximately 0.1 mW.
Single Point Responsivity
We provide a single point responsivity, at 2.5 µm, for all of our lead salt detectors. Use these factors with confidence for the cooled detectors; use them for guidance with the room temperature units. Use the typical responsivity curves (Fig. 2) to approximate responsivity at other wavelengths.
Detector Systems
All PbS and PbSe detector packages for Merlin™ include:
- Detector element
- Detector housing with built-in bias supply and preamplifier
- All necessary interconnecting cables
You will also need to order:
- Model 77055 Cooler Controller for the cooled systems
- MerlinTM Control Unit
- Chopper
