Description
No detector has a constant spectral responsivity under all conditions of use. For instance, the responsivity of photodiode detectors falls off above a certain incident power level due to saturation effects. Full evaluation of a detector requires characterisation of such effects. This information allows the identification of the detector with the best performance for a particular application. Also, a detector to be used for calibration purposes should be fully characterised in order to evaluate the uncertainty of such calibrations.
In all cases the detector under test is compared with a standard detector of known spectral responsivity / quantum efficiency.
300F Monochromator is used to select a narrow wavelength band from a broad band quartz halogen lamp. Wavelength range of monochromator is between 200 – 2000 nm. The wavelength can readily be tuned continuously allowing measurement of spectral responsivity across the wavelength range for which the detector is used
Specifications
| Optical path | : | Czerny-Turner configuration |
| Scanning range | : | 200 – 2000 nm (UV requires Special Lamp) System comes with Quartz Halogen Lamp which Wavelength Range is 350 – 2000 nm for UV range less than 350 nm special lamp is required |
| Resolution | : | 0.1nm (@ 546 nm, 10 μm slit width) |
| Wavelength accuracy | : | ≤ 0.2 nm |
| Wavelength repeatability | : | ≤ 0.1 nm |
| Incident power levels | : | 10-10 – 10-3 W range |
| Laser Wavelength | : | 532 nm |
| Chopper frequency | : | 400 Hz |
| Maximum beam | : | 15 x 10 mm |
| Voltage range | : | 1 to -1 V |
| Resolution | : | 5 mV |
| Current range | : | 0.1 uA to 0.75 A |
HOLMARC Model: HO-PDC-01 designed for characterisation / measurement of the following detector parameters:
Linearity range : This is the range of incident radiant power levels over which the detector output varies linearly with incident power. (Laser-based methods is used for measuring saturation threshold of a detector).
Spatial non-uniformity of response : The variation of responsivity across the active area of a detector is determined by scanning a small spot of radiation at a selected wavelength over the surface.
Noise Equivalent Power (NEP) : the incident radiant power at a specific wavelength and modulation frequency necessary to produce a signal-tonoise ratio of 1 at the detector output.
Temperature coefficient of response : the variation of responsivity with temperature
Detector shunt resistance : the slope of the current-voltage curve of a photovoltaic detector at zero-volt bias.
