Fluorescence emissions detector

摘要

A light source is gated ON and OFF in response to a pulsed signal. Photo emissions from the light source are coupled to a material under test. Resonant fluorescent emissions from the material are coupled to a photodiode. Current from the photodiode is coupled into an amplifier system comprising a first and second amplifier stages. The first amplifier stage is gated to a low gain when the light source is turned ON and the gain is increased when the light source goes from ON to OFF. The second amplifier stage has digitally programmable offset and gain settings in response to control signals. The output of the second amplifier stage is digitized by an analog to digital converter. A controller generates the pulse control signal and the control signals.

主权项

1. A method of detecting fluorescence emission from a target comprising:
irradiating the target with a light pulse, wherein the light pulse transitions between an on state and an off state;
wherein a first electrical amplifier gain of a first electrical amplifier is reduced while balancing a source impedance of the first electrical amplifier in response to the light pulse being in the on state; andwherein the first electrical amplifier gain of the first electrical amplifier is increased while balancing the source impedance of the first electrical amplifier in response to the light pulse being in the off state; receiving a fluorescence emission signal in response to irradiating the target with the light pulse, and thereby generating an electrical signal; applying the first electrical amplifier gain to the electrical signal using the first electrical amplifier to generate a first amplified electrical output signal; level shifting an input offset voltage of a second electrical amplifier in accordance with the first amplified electrical output signal, wherein level shifting the input offset voltage reduces a direct current (DC) voltage offset of the first amplified electrical output signal; applying a third gain to the first amplified electrical output signal to generate a second amplified electrical output signal; and applying an authentication algorithm to the second amplified electrical output signal, and thereby validating the target.