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19 Nov 2019
One formula given for the specific detectivity D* is: D* = where Ao is the area of the detector, B is the measurement bandwidth (usually taken to be 1 Hz), P the incident optical power, and Vs is the signal voltage and Vn the noise voltage. Another form was given as: D* = where is the quantum efficiency, hv is the photon energy, and I the background irradiance. Show that the two definitions are equivalent. Hint: Show that the dimensions are the same. Hint: The Background-limited NEP (Noise Equivalent Power) is (NEP) BL = vn Hint: The Bandwidth B of a filter which averages for a time tau is B = 1/(2 tau). Hint: The Background irradiance I = PB/Ad Hint: Try to calculate the various currents. Remember that power is proportional to current squared.
One formula given for the specific detectivity D* is: D* = where Ao is the area of the detector, B is the measurement bandwidth (usually taken to be 1 Hz), P the incident optical power, and Vs is the signal voltage and Vn the noise voltage. Another form was given as: D* = where is the quantum efficiency, hv is the photon energy, and I the background irradiance. Show that the two definitions are equivalent. Hint: Show that the dimensions are the same. Hint: The Background-limited NEP (Noise Equivalent Power) is (NEP) BL = vn Hint: The Bandwidth B of a filter which averages for a time tau is B = 1/(2 tau). Hint: The Background irradiance I = PB/Ad Hint: Try to calculate the various currents. Remember that power is proportional to current squared.