Probing Quantum Phenomena using Fiber Bragg Grating Sensor

Quantum sensing has now become one of the most advanced, rapidly growing areas of research, which permits precise scale of measurement. We have experimentally demonstrated a novel method of probing quantum phenomena of light-matter interaction especially the fluorescence by utilizing matured fiber Bragg grating (FBG) technology. In response to the incident excitation, quantum electrodynamic response of fluorophores coated on the FBG causes a shift in the Bragg wavelength. The Bragg wavelength shift is dependent on excitation wavelength and intensity, where the increased light-matter interaction leads to a higher shift in the Bragg wavelength. Our sensor could probe the fluorescence at microscopic scale showing Bragg wavelength shift of 10 pm per 400 μW of incident excitation power. Capturing fluorescence at this small scale with microwatt of excitation power can be potentially helpful for biosensing applications where the photodamage limit of excitation power is crucial for the dynamic measurement of biological specimens.