Zixin Wang

Three-dimensional measurement of a tightly focused laser beam

The spatial structure of a tightly focused light field is measured with a double knife-edge scanning method. The measurement method is based on the use of a high-quality double knife-edge fabricated from a right-angled silicon fragment mounted on a photodetector. The reconstruction of the three-dimensional structures of tightly focused spots is carried out with both uniform and partially obstructed linearly polarized incident light beams. The optical field distribution is found to deviate substantially from the input beam profile in the tightly focused region, which is in good agreement with the results of numerical simulations.

Fourier Spectrometer based on Wide-range and Phase-locked Michelson Interferometer with Femtosecond Laser Excitation

A wide-range and phase-locked Michelson interferometer technique is described. This technique combined with femtosecond laser is used to measure the spectrum of the rare-earth ion Nd:YVO4, which presents very high signal to noise ratio of interferometric intensity output and higher spectral resolution than traditional grating spectrophotometer.

Fourier Spectrometer based on a wide-range and nanometer stabilized Michelson Interferometer

A high signal-to-noise-ratio (SNR) and resolution Fourier spectrometer based on a wide-range and phase-locked Michelson interferometer is presented. A novel arrangement of a step motor, a nanometer resolution piezoelectric actuator and an active PID control loop ensures that the Michelson interferometer has a phase stabilized scanning range virtually without limit, resulting in the Fourier spectrometers high resolution and high SNR. Several experiments demonstrate that this spectrometer, using light sources such as write LED (WLED) and femtosecond laser, can accurately acquire the spectrum information of a given sample as well as the light source itself in a resolution of nanometer order.