A high-density multi-point LAPS set-up using a VCSEL array and FPGA control

AbstractA new LAPS (light-addressable potentiometric sensor) set-up will be introduced, in which the light sources are miniaturised by the utilisation of a VCSEL (vertical-cavity surface-emitting laser) array to increase the measurement spot density. An FPGA (field-programmable gate array) is used to generate modulation signals for an individual illumination of each measurement spot of the LAPS. The new set-up can operate a large number of measurement spots simultaneously by reading out the sum-photocurrent and separate the signals of the individual measurement spots by FFT analysis. The frequency, amplitude and offset of the modulation signal can be configured for each measurement spot programmatically