Abnormal profile sample
- Principle of Measurement
Standard ABR measure by transmitting a laser beam through a sample. Therefore, if the sample does not have a parallel plane, such as a lens or prism, it cannot be measured as it is. The simplest way to solve this problem is to place the sample in a transparent cell as shown in the figure below, and immerse it in a liquid with the same refractive index as the sample (index matching oil). Since the sample and the liquid have the same refractive index, the measurement light is not refracted by the shape of the sample. Therefore, it is possible to measure samples of any shape. The index matching oil is commercially available, and can be mixed with peanut oil, bromonaphthalene, methylene iodide, etc.