| 摘要 |
Objects to be examined, such as tissue or any cellular or crystalline material, e.g. semiconductor wafers, are placed in a region of confluence of two interfering coherent beams of radiation which are at the same frequency and phase and at a frequency to which the object is semitransparent. The beams are produced by separate sources or by refraction by a Fresnel biprism or any other interferometer structure. An off-axis parabolic reflection system is also disclosed. The interference fringe phase and amplitude perturbation produced by the object is detached and examined to derive information regarding physical properties of the object or abnormalities in its structure. Such abnormalities, as fractures or latent stresses in a semiconductor wafer or the presence of tumors in biological tissue can be determined. Chemical characteristics of living tissue is determined by sweeping the frequency of the coherent radiation over a band which includes the absorption bands of given chemicals such as hydrogen, oxygen, sodium, and other materials which are representative of the structure of living tissue. The frequencies employed may be in the microwave band millimeter band or higher. |
