In the paper, gold nanoparticles film is fabricated based on nanolithorgraphy. The nanostructure and the optical
properties are studied by SEM and spectroscopy. We design a spectroscopy acquisition system, gain the peak
absorption wavelength by fitting the data collected, then we analyze its localized surface plasmon resonance effect
by experiments of sucrose with different concentration. It shows a red-shift of peak absorption wavelength when
the refractive index of external medium of gold nanoparticles film changes.
Core-shell gold nanoparticles film was fabricated by using nanolithography and self-assembly monolayer technology.
The film exhibits unique optical properties and has strong surface enhanced Raman scattering activity. The relationship
between nanostructure and surface electrical field was studied by employing pyridine as the SERS probe. It was found
that particle size and interparticle space are of important factors. The enhanced ration is measured more than 104.
Surface plasmon resonance has become a strong tool in the bio-interaction analysis since the first introduction by
BIACore in 1990. Most research work have been carried out by employing angle interrogation, which is well known as
angle scanning SPR system. Wavelength interrogation SPR is another method to trace the bio-interaction in real time.
Due to the broad band excitation, it owns great potentials in photonic studies. In this paper, the sandwich structure of
prism/gold/sample is studied by a home-made simulation program based on matrix of Fresnel reflection coefficients. The
structure of 3 layers to 5 layers are studied in detail.
Motion analysis of Micro-electro-mechanical system (MEMS) is a powerful diagnostic tool enabling evaluation of the dynamic behaviour and the status of MEMS. A backscattering differential laser Doppler system is presented. The working principle and optical diagram of the system are explained in detail. In accordance with the characteristic of the measurement system, high-performance phase-locked loop is used to detect a weak measurement signal. Then measurement signal is transferred to computer and further analyzed there. Furthermore, a laser focusing method is described to improve the measurement. The focusing system is composed of a spatial filter and an aspheric lens C240TM-A, and focal spot size is less than 50 um. The silicon micromachined resonator is used as an example in experiments, and the resonant frequencies and the mean amplitude of MEMS are determined. Experimental results indicate that dynamic characteristics of MEMS can be measured well.
We are using a gold nanoparticle coated film to achieve high spatially resolved biosensing that is based on localized
surface plasmon resonance (LSPR). This special film possesses the unique optical properties of being not sensitive to
the changes of incident angle and relies exclusively on the spectral shift of absorption peak for biosensing. This
uniqueness enables it to be compatible with high numerical aperture (NA) optics and to achieve high spatial resolution.
We demonstrate a spatial resolution of 25μm assuming a maximum of spectral fluctuation of 0.1nm is acceptable.
For the first time, time varying speckle analysis is made in the differential structure and time-space correlated function has been deduced, in which the relationship between Doppler frequency shift and speckle time correlated function is got. The traditional method can obviously analyze the Doppler frequency shift of the single particle tested, which is suitable for the condition of fluid measurement, while the signal is Doppler burst. Different from it, for the solid scattering surfaces, signal is similar to the continuous one and signal losing happens randomly due to the surface structure. Superior to the traditional one, our analyzing method connects the Doppler frequency shift with the scattering field, which has the advantage for the analysis of the signal losing.
For the first time the displacement remote measurement was realized in this paper, utilizing laser Doppler Effect. The Doppler shift of differential structure was analyzed theoretically. The system of differential optical-acoustic modulating structure, big aperture collecting backward scattering light, and compensating the losing signal by computer tracking software was designed. The displacement measurement of paper and metal at a distance of 10 meters long has been achieved with an accuracy of 0.4%.
A new measurement of the curved surface has been developed. The paper provides an effective, real time and dynamic optical measurement which is suitable for the measurement of airfoil, turbine blade, car and tank's curved surface. The system consists of a laser probe, a charge couple device (CCD), a computer, three servomotors. Consideration is also given to the design of the laser probe and CCD driving circuit.