Wavelength framing technique based on a diffractive optical element

Framing camera is a powerful tool to investigate the ultrafast phenomena in chemical reaction process. Wavelength framing technique is one of the key technologies in the development of framing cameras. The wavelength resolution of the images generated by wavelength framing system determines the interval time of the wavelength framing camera, that is, the time resolution of the wavelength framing camera. In this paper, a wavelength framing system based on a diffractive optical element (DOE) and a band-pass filter (BPF) was set up. The wavelength characteristics of the wavelength framing system were simulated utilizing the theory of multi-beam interference. The central wavelength of each image got from the system, which varies with the position relationship between DOE and BPF, has been obtained. Experiments were carried out through imaging a target of 6 mm × 6 mm by using the wavelength framing system. The spectral characteristics of each image were also studied experimentally. The result we have got proves that the system we have generated can achieve 16-frame imaging, every image has different spectral properties. For the target with a size of 6 mm × 6 mm, the resolution of a single image got from the system is 610 × 610, and the central wavelength ranges from 784 nm to 814 nm. The average difference in central wavelength between adjacent images is 1.95 nm. If the dispersion of the incident pulse light source is 0.46 ps/nm, the time resolution of the system is 0.9 ps.