为借助激光全息进行无损检测，获得位相物体的信息，对位相物体激光全息二次曝光法无损检测进行了研究，指出一般的二次曝光法测位相物体典型光路的缺点，提出了物光波2次通过样品的改进方案。利用此方案对一些位相物体(如普通玻璃和有机玻璃)作了无损检测实验，得到了较满意的实验结果。与普通检测方法相比，该方法具有精度高、结果直接可靠、不损伤物体等诸多优点。对改进方案稍作改动，即可用于塑料制品和玻璃制品生产线对加工产品进行在线产品质量监控。

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.