Quantum Efficiency estimation using LIFO

Quantum Efficiency estimation using LIFO

Introduction

This article describes the characterization method of the quantum efficiency (QE) of Prophesee Gen3.1, Gen40 and Gen41 sensors

Method 

we used the LIFO (Light Input Frequency Output) feature of the sensor .
An on-chip circuit converts the instantaneous photocurrent of the whole pixel array into a frequency signal that can be read out from the SPI bits “lifo_counter <25:0>", or the external pin Fout. The signal encodes the absolute illumination of the scene in the field of view of the sensor.

Calculated QE

The quantum efficiencies were calculated with different LED.  

Iph=Ev×q×Apd×QE×λh×c

Iph        # current per pixel, so it is absolute value of the applied current devide by the number of pixel (1280x720)

λ                    # Wavelength

Ev                          # Input illuminance (light level)

QE                      # quantum efficiency (function of wavelength)

Apd      # photodiode area (4.86 µm x 4.86 µm)

q = 1.6 10-19 C                # electron charge

h = 6.64 10-34 J.s             # Planck constant

c = 3 108 m/s                   # light speed

QE=IphEv×h×cq×Apd×λ

With the multimeter Iph is acquired (current divided by the number of pixels), then the ration Iph/Ev is calculated.

The QE is depending on wavelength can be seen on this page.


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