科研之友
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摘要
A null test is described for a deeply aspheric lens. This test uses a spherical mirror that would be unable to produce enough distortion of the reflected wavefront to compensate for the asphericity of the lens if this were to be tested in air. Immersion of the lens (n = 1.523) in a small water tank (n = 1.333) reduces the wavefront distortion produced by the lens to about one-third of its value when in air, which is sufficient to allow compensation. The sensitivity of the test is also reduced by a factor of nearly 3, but this is of little importance in the application described below. It is thought that this use of a water tank may be original.
- 出版日期2011-9-1
