Authentication systems, authentication devices, and methods for authenticating a value article

An authentication device comprising:

• an exciting light source configured to produce light;
• an optical filter configured to filter radiation comprising light from the exciting light source and emitted radiation from a luminescent material and to produce filtered radiation comprising emitted radiation from the luminescent material, wherein the luminescent material excites by absorbing light and emits radiation with a decay time of greater than 0.05 milliseconds;
• a photodetector configured to detect the filtered radiation after excitation using the modulated light to produce a detected radiation signal;
• a signal manipulation circuit configured to electronically manipulate the detected radiation signal to reduce an effect of light from the exciting light source on an authentication determination based on the detected radiation signal;
• and
• an amplifier configured to amplify the detected radiation signal after the detected radiation signal is electronically manipulated.

An authentication system comprising:

• an article path having an inlet, wherein the inlet has the capacity to receive a value article;
• an authentication device disposed in the article path, wherein the authentication device comprises:
• an exciting light source configured to produce light;
• an optical filter configured to filter radiation comprising light from the exciting light source and emitted radiation from a luminescent material and to produce filtered radiation comprising emitted radiation from the luminescent material, wherein the luminescent material excites by absorbing light and emits radiation with a decay time of greater than 0.05 milliseconds;
• a photodetector configured to detect the filtered radiation to produce a detected radiation signal;
• a signal manipulation circuit configured to electronically manipulate the detected radiation signal to reduce an effect of light from the exciting light source on an authentication determination based on the detected radiation signal;
• and
• an amplifier configured to amplify the detected radiation signal after the detected radiation signal is electronically manipulated to produce an amplified electronic signal;
• circuitry having the capacity to convert the amplified electronic signal or data derived therefrom to an authentication output;
• and
• a user interface in electronic communication with the authentication device, wherein the user interface has the capacity to communicate an authentication output to a user.