Real-time interferometry with high speed and precision for transient flow field and its applications

It is necessary that the transient flow field which leads to variation of temperature, pressure, turbulent and etc. can be tested well by using real-time interferometry with high speed and precision. A radial shearing interferometer based on the method of spatial phase modulation was proposed. The system,which consisted of Nd: YLF diode pumped solid pulse laser of which wavelength is 1 053 nanometers, a novel synchronization control system of high speed imaging, can realize common-path interference, and transient, high speed measurement without reference surface for various wavefront of continuous and transient flow field. The speed of image acquisition in pixels dimensions 512512 can reach 1 000 frames per second. The theory of wavefront reconstruction was validated by the computer simulation with an 1/1 000 wavelength error. Comparing the system with ZYGO interferometer, the RMS error is better than 1/15 wavelength with good repeatability. The system has already been used in the Inertial Confined Fusion (ICF) system to test the pulse laser wavefront, and will probably be used in the fields where the wavefront distortions are so large that high speed and real-time testing must be required, for instance, aviation, space flight, aero-optical, etc.