Design and Fabrication of a Cost-Effective Optical Notch Filter for Improving Visual Quality

Abstract

This study presents a multilayer design and fabrication of an optical notch filter for enhancing visual quality. A cost-effective multilayer design of notch filter with low surface roughness and low residual stress is proposed. A 9-layer notch filter composed of SiO2 and Nb2O5 with a central wavelength of 480 nm is prepared by electron beam evaporation combined with ion-assisted deposition. The optical transmittance, residual stress, and surface morphology are measured by a UV/VIS/NIR spectrophotometer, Twyman-Green interferometer and field emission scanning electron microscopy (FE-SEM). The transmittance of the notch filter at the central wavelength is above 15%, and the average transmittance of the transmission band is about 80%. The residual stress of the notch filter is −0.235 GPa, and the root mean square surface roughness is 1.85 nm. For improving the visual quality, a good image contrast can be obtained by observing the microscopic image using the proposed notch filter.

Special Issue “Advanced Coating Technology by Physical Vapor Deposition and Applications”

“…Optical coatings that combine high and low refractive index thin films have many applications. Examples include distributed Bragg reflectors [12], notch filters [13][14][15][16][17], antireflective coatings [18][19][20][21][22], narrow-bandpass filters [23][24][25][26][27] and flexible displays [28,29], etc. These application components have received a great deal of attention.…”

“…The notch filter with a center wavelength of 480 nm is based on a 9-layer non-quarter-wave stack design, and the transmittance at the center wavelength is about 15%. The multilayer notch filter, produced by the electron beam evaporation method combined with ion-assisted deposition technology, has low residual stress and low surface roughness [17].…”