The invention brings forward application of a tapered nanometer
optical fiber. The smooth tapered nanometer
optical fiber extends into a micro-channel of a
micro fluidic chip substrate from a taper tip and is used as an optical
waveguide for introduction of
fluorescence exciting light of a to-be-detected object. According to a technical scheme provided by the invention, the tapered nanometer
optical fiber is applied as the optical
waveguide for introduction of
fluorescence exciting light of the to-be-detected object, the taper tip of the nanometer optical
fiber is inserted into the micro-channel of the
micro fluidic chip substrate and corresponds to a designated to-be-detected point, the
fluorescence exciting light irradiates and enters from a larger end of the nanometer optical
fiber, and the nanometer optical
fiber introduces the exciting light into the micro-channel and allows the exciting light to converge and then be shot out from the taper tip; fixed-point fluorescence excitation is carried out on the designated to-be-detected point, so interference of the exciting light on a fluorescence
signal of a sample can be effectively avoided, and detection sensitivity and reliability are improved. The invention further brings forward a micro-fluidic
chip and a preparation method thereof. The micro-fluidic chip not only has improved detection sensitivity and reliability but also enhances the integration level of a fluorescence excitation apparatus and the chip. The preparation method is simple, direct and highly efficient.