detectors - Optical Detection Transduction: convert radiant...

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Optical Detection Transduction: convert radiant (optical) power into electrical signal Photon detectors Multichannel detectors Sensitivity, linearity, dynamic range, SNR Response: f( λ ), photon arrival rate
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Transducer Characteristics Sensitivity Responsivity: R( λ ) Rms sig out X(voltage, current, charge)/rms incident radiant power Φ Sensitivity: Q( λ ) Q( λ ) = dX/d Φ Spectral Response R( λ ) vs. λ ; Q( λ ) vs. λ
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Transfer Function X( λ ) Φ ( λ ) Slope = sensitivity (dX/d Φ ) Responsivity (X/ Φ ) at given incident power Linearity, Q( λ ) constant, independent of Φ Dynamic Range : total range of incident radiant power where transducer responds LDR = linear dynamic range, typically in power of 10 Other “X” factors: temperature, bias voltage
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Transducer Temporal Response Stability: constancy of Q or R vs. time Degradation, hysteresis Response speed – Time constant: τ = 1/2 π f c • f c = 3-db roll off frequency, i.e. at when R has fallen to 0.707 of max value for sinusoidal input Rise time: time for output to rise from 10-90% of final value for instantaneous increase in radiant power
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Detector Limits Dark Signal Electrical output in absence of radiation Generally thermal: e.g. emission of electrons, charge carrier movement
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This note was uploaded on 04/15/2008 for the course COMP CETU311 taught by Professor Butler during the Spring '08 term at Northeastern.

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detectors - Optical Detection Transduction: convert radiant...

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