A method of measuring the optical transfer function of optical systems is studied by means of a Fourier-transform holographic technique which is used to produce the point spread intensity and to transforming it into an optical transfer function. In this method, not only the modulation—but also the phase—characteristics of optical transfer function can be obtained two-dimensionally.
Some problems with the application of holography to interferometry of specular-reflecting objects and new possibilities for the use of holograms as test glasses are discussed.
Accurate exposure timing is required for photographically recorded holograms. One solution is to use photographic timing shutters, but these have limitations particularly when multiple exposures are required, as in lapsed-time holographic interferometry. To overcome these limitations the authors have devised a light weight shutter energised by an in-expensive timing circuit.
An output laser reflector is described which is remarkably damage resistant due to the use of a titled total reflexion roof prism. The reflectance of this reflector can be continuously varied by turning the prism about its edge. It has been used for mode-locked pulses of several gigawatts without any damage. Since the reflectivity is independent of the wavelength, it can be used for different types of lasers.
A new laser image—speckle interferometer, a device used for looking at vibrational modes on defusely reflecting surfaces, has been designed. The design makes it possible to provide a reference field in the instrument that is substantially free from spurious pattern. This field interferes with a speckled image so giving a more intense image field. As larger surfaces may be viewed with lower power lasers, the method offers an attractive alternative to strictly holographic methods.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：