Stimulated emission-based optical detection system

摘要

The present invention provides an optical detection system comprising an illumination unit and a detection unit. The illumination unit comprises two laser beams of two different wavelengths. One beam is used to excite targeted molecules in a sample to their excited states. The other beam is used to induce the excited molecules in the sample to generate a stimulated emission signal. The stimulated emission signal can be used for long-distance detection due to its coherent property. Its extraction from the detection unit can be realized by demodulating the second beam's intensity change.

主权项

1. An optical detection system, comprising:
an illumination unit, comprising:
an excitation beam, being modulated at a selected frequency, to excite targeted molecules in a sample to their excited states; anda stimulation beam, to induce the excited molecules in the sample to generate a stimulated emission signal, wherein photons of the stimulated emission signal are in coherence with photons of the stimulation beam; and a detection unit, comprising:
a photo-detector, to detect a signal from the sample, anda lock-in amplifier demodulates a electronic signal from the photo-detector with the selected frequency, to distinguish the stimulated emission signal from the stimulation beam for measuring the change of the intensity of the stimulated emission signal.