PHASE GRATING TYPE OPTICAL LOW PASS FILTER

摘要

PURPOSE: A phase grating type optical low pass filter is provided to achieve the optical low pass filter which increases the optical transferring function passing through a low frequency band and restraints the optical transferring function passing through a high frequency band. CONSTITUTION: A phase grating type optical low pass filter restraints the high frequency and allows the low frequency to pass therethrough. The phase grating type optical low pass filter includes the first grating which generates a zero phase transition. The second grating is arranged at a right side of the first grating and a lower portion of the first grating so as to generate a Φ phase transition. At a diagonal portion of the first grating, there is provided the third grating which generate 2Φ phase transition.