Design and Fabrication of Laser Protective Lenses Based on Multilayered Notch Filter with Low Residual Stress and Low Surface Roughness

Abstract

We present a new laser protective lens based on a multilayered notch filter design with low residual stress and low surface roughness. An18-layer notch filter was prepared by electron beam evaporation with an ion-assisted deposition technique, which was composed of SiO2 and Nb2O5 with a center wavelength of 532 nm. The optical transmittance, residual stress, surface roughness, and surface morphology were measured by a UV/VIS/NIR spectrophotometer, Twyman–Green interferometer, scanning probe microscope, Linnik microscopic interferometer, and field-emission scanning electron microscopy (FE-SEM). The transmittance of the notch filters at center wavelength is 0.2%, and the average transmittance of the transmission band is about 70%. The residual stress of the notch filter is −0.298 GPa, and the root mean square surface roughness is 1.88 nm. The experimental results show that the optical transmittance meets the design requirements.

Optical Interference Filters Combined with Thin Film Residual Stress Compensation for Image Contrast Enhancement

“…Therefore, device designers usually do not have sufficient information on residual stress values when designing thin-film devices [27]. In this study, the residual stress in a singlesided coated notch filter was evaluated using a Twyman-Green interferometer [16,17] and the residual stress in a double-sided coated notch filter was measured using a Mach-Zehnder interferometer. To evaluate the effect of double-sided thin-film coating on residual stress compensation, a 620 nm filter was deposited on the first surface of the B270 glass and a 480 nm filter was deposited on the second surface of the B270 glass.…”

“…We designed and manufactured the optical notch filter in order to see more detail by making it more visible against the background. In 2021, a lower-stress laser protective lens based on a multilayer notch filter was presented [17]. The transmission of the proposed notch filter was 0.2% at the central wavelength of 532 nm, and the average transmission of the transmission band was about 70%.…”

Laser Protection Properties of Multi-Band Non-Regularized Highly Reflective Films

“…To reduce the risks associated with laser use, laser protection lenses must be designed to protect against potentially harmful laser wavelengths. In addition, developing safety rules during laser use [1], preparation of laser protection glasses for specific wavelengths [2], developing optical limiting materials [3], and designing and preparing trap filters [4] were proposed. Therefore, laser protection technologies [5] must be developed to reduce industrial and medical costs while realizing widespread laser applications.…”

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

“…In other words, the notch filter can selectively reflect a portion of the spectrum while transmitting all other wavelengths. In the related literature, the use of high-end multilayer film manufacturing technology includes the advancedplasma-source (APS) assisted electron beam evaporation [1], plasma assisted reactive magnetron sputtering (PARMS) [2][3][4], HELIOS (Leybold Optics) magnetron sputtering [5,6], ion-assisted electron beam evaporation [7], etc. Among them, electron beam evaporation technology has the potential for industrialized mass production and application.…”

“…They did not address the issue of residual stress control and image contrast of the notch filters. In our previous work, a new laser protective lens based on a multilayered notch filter design with low residual stress and low surface roughness was presented [7]. An18-layer notch filter was prepared by an electron beam evaporation with ion-assisted deposition technique, which is composed of SiO 2 and Nb 2 O 5 with a center wavelength of 532 nm.…”