Development of a novel diffractive optical element which detects the center wavelength of a light source using a multiplex fresnel hologram

In our previous study, it was cleared that a Fresnel hologram was able to image the design pattern even if the wavelength of incident light had wavelength width of about 50 nm to the design wavelength. In this study, we propose a novel diffractive optical element which detects the center wavelength of a light source using a multiplex Fresnel hologram. Moreover, the designed Fresnel holograms were evaluated by experiments using spatial light modulators. The diffraction images of designed Fresnel holograms were taken with CCD camera. Then, the center wavelength of light source was detected from the cross correlation value between the design image and the diffraction image using image processing. As a result, it was found that the diffraction efficiency becomes the maximum value when the design wavelength coincides with the center wavelength of the light source.