FLUORESCENCE EMISSIONS DETECTOR
First Claim
1. A system for detecting resonant fluorescence comprising:
- a light emitting diode (LED) configured to emit pulsed photoemissions towards a target n response to a pulsed signal;
a photodiode configured to (1) receive resonant fluorescence emissions from the target, the resonant fluorescence emissions a response to the pulsed photoemissions, and (2) generate a current in response to the received resonant fluorescence emissions; and
an amplifier system having first and second stages, wherein the first stage is configured to receive (1) the current from the photodiode, and (2) a gating signal as a function of the pulsed signal, the first stage further configured so that the gating signal gates the first stage to have a first output with (1) a first gain when the LED is activated to emit one of the pulsed photoemissions, and (2) a second gain when the LED is deactivated, wherein the second stage is configured to receive control signals and the first output of the first stage, the second stage having a second output and having a gain and offset configured to respond to the control signals to produce a linear dynamic range for a signal at the second output of the second stage that is an analog of the resonant fluorescence emissions from the target.
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Accused Products
Abstract
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.
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Citations
20 Claims
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1. A system for detecting resonant fluorescence comprising:
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a light emitting diode (LED) configured to emit pulsed photoemissions towards a target n response to a pulsed signal; a photodiode configured to (1) receive resonant fluorescence emissions from the target, the resonant fluorescence emissions a response to the pulsed photoemissions, and (2) generate a current in response to the received resonant fluorescence emissions; and an amplifier system having first and second stages, wherein the first stage is configured to receive (1) the current from the photodiode, and (2) a gating signal as a function of the pulsed signal, the first stage further configured so that the gating signal gates the first stage to have a first output with (1) a first gain when the LED is activated to emit one of the pulsed photoemissions, and (2) a second gain when the LED is deactivated, wherein the second stage is configured to receive control signals and the first output of the first stage, the second stage having a second output and having a gain and offset configured to respond to the control signals to produce a linear dynamic range for a signal at the second output of the second stage that is an analog of the resonant fluorescence emissions from the target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for detecting resonant fluorescent emissions from a target, comprising:
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irradiating the target with light from a pulsed light source, thereby causing the target to emit resonant fluorescent emissions, the pulsed light source receiving a signal that activates and de-activates the pulsed light source to gate the light ON and OFF; receiving the resonant fluorescent emissions from the target by a photoconductor to thereby produce a current modulated by the received resonant fluorescent emissions; coupling the current from the photoconductor to an amplifier system comprising a first stage amplifier that converts the current to a voltage output and a second stage amplifier with programmable gain and offset that receives the voltage output and produces an amplifier output; reducing a gain and balancing source impedances of the first stage amplifier in response to the signal that activates the pulsed light source ON; and increasing the gain and balancing source impedances of the first stage amplifier in response to the signal deactivating the pulsed light source from ON to OFF. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification