Photonics

The detectors do not require a chopper. A chopper is often used to modulate the source, allowing band limited amplification of the signal and thereby increasing the signal/noise ratio. If the [...]

As the detector operating temperatures decreases, the detectivity, responsivity, and spectral response improves. Source (with permission to reproduce): http://optodiode.com/resources.html

Spectral response defines the sensitivity of a detector to radiation at a various wavelengths. PbS detectors are sensitive in the 1-3µm region and PbSe detectors are sensitive in the 1-5.5µm [...]

Detectivity is defined as the signal to noise ratio of the detector normalized by detector area. As the detector temperature decreases, the detectivity increases. Please refer to Section 4 in the [...]

(Note: These specifications are approximate figures that provide data for a general comparison). Temperature Parameter InGaAs (std.) InGaAs (ext.) PbS PbSe 300°K λ range (µm) 0.7 – 1.7 1.2 [...]

Typically photoconductive detectors (PbS) are not characterized by quantum efficiency because, theoretically, they are completely efficient (100% QE), unlike photovoltaic detectors (InGaAs). A [...]

Yes, as long as the pulse width of the laser is long enough, the wavelength is in the correct range, and the power density is within limits. Please note the detector time constant of the model [...]

The maximum rated element temperature for PbS detectors is +65°C and for PbSe it is +55ºC. This refers to the actual temperature limits that the detector surface can reach, not temperature that [...]

Typically, when we talk about linearity we are referring to responsivity linearity. When the film runs out of free carriers that would be forced into conduction by incoming photons, the detector [...]

The first step when this issue comes up is to check the source intensity. If the intensity of the source is too high (beyond 1mW/cm2), the detector material will heat up to a point that changes [...]