Pulsed laser diodes and pulsed LEDs used in range finders, environmental scanners and image capture emit pulses with a few nanoseconds length of very high peak power. To measure the temporally resolved pulse shape fast detectors are required. These are usually small-area photodiodes with diameters of sometimes significantly less than 1 mm. The small detector area of the photodiodes results in metrological limitations: The extent of the laser spot is larger than the active area of the photodiode and thus does not allow measurement of the radiant power (W). The position of the photodiode in the laser spot is critical because of possible modes (inhomogeneous laser spot). Very small photodiodes cannot be calibrated absolutely. Attachment optics used to focus the laser spot on the photodiode surface cannot be calibrated. The electronic wiring of the photodiodes required for short pulse lengths further limits the calibration capability. With the ISD-1.6-SP series of detectors in combination with the P-9710-2 and P-9710-4 optometers, Gigahertz-Optik provides a way to determine the absolute peak performance of pulsed lasers and pulsed LEDs. Function and structure: The detector incorporates two photodiodes within a compact integrating sphere assembly. The first photodiode has a short rise time and hence, in conjunction with a sufficiently fast optional oscilloscope, allows the measurement of the relative time resolved pulse shape(pulse length, half-width, peak power). The second photodiode measures the absolute pulse energy (in joules) of a single pulse or pulse train.
Технические характеристики
CharacteristicsDetected entitypowerTechnologyphotodiodeOther characteristicscompact
