Nondestructive test for phase objects by secondary exposure laser holography

In order to carry out nondestructive test by laser holography and to get the test data of phase object, nondestructive test of phase objects by secondary exposure laser holography is studied. The disadvantages of the traditional beam path test for phase objects with the method of secondary exposure were analyzed. Therefore, an improved scheme, which suggests that the object light wave should pass through the sample twice, is put forward. This scheme was applied to the nondestructive test for some phase objects such as normal glass and organic glass, and satisfactory results were achieved. In comparison with the traditional test methods, this scheme has some features such as high precision, high reliability and nondestructive direct test, etc. With a little change, the device can be used in online quality control for plastic and glass production.