Novel optical sensors fabricated by Si micromachining

In this study, three novel optical sensors are described. They are the pinhole integrated with the surrounding photodiode, the transmission type position sensor fabricated on the Si mesh structure, and the photodiode thinner than the optical wave length in the active layer. These sensors have unique optical functions as well as photodetection. These devices offer new concepts and easy construction of the optical systems to realize applications, which have been complicated or laborious in the conventional way. They are automatic alignment of the pinhole, detecting many points along a straight line, and detecting the intensity profile of the interference of the standing wave respectively. Each sensor absorbs only a part of the incident light beam and the rest passes through the sensor and enables to detect the information of the incident light beam not disturbing the optical field very much. The almost light beam continues to propagate to the down stream, and the transmitted beam can be used for the further function.