Chirped mirrors （CMs） are designed and manufactured. The optimized CM provides a group delay dispersion （ODD） of around -60fs^2 and average reflectivity of 99.4% with bandwidth 200 nm at a central wavelength of 8...Chirped mirrors （CMs） are designed and manufactured. The optimized CM provides a group delay dispersion （ODD） of around -60fs^2 and average reflectivity of 99.4% with bandwidth 200 nm at a central wavelength of 800nm. The CM structure consists of 52 layers of alternating high refractive index Ta2O5 and low refractive index SiO2. Measurement results show that the control of CM manufacturing accuracy can meet our requirement through time control with ion beam sputtering. Because the ODD of CMs is highly sensitive to small discrepancies between the layer thickness of calculated design and those of the manufactured mirror, we analyze the error sources which result in thickness errors and refractive index inhomogeneities in film manufacture.展开更多
The experiment setup of a reflecting combination device, which has more advantages than a transmitting combination device, is designed in this study. To achieve angular spectrum selectivity, only one type of reflectiv...The experiment setup of a reflecting combination device, which has more advantages than a transmitting combination device, is designed in this study. To achieve angular spectrum selectivity, only one type of reflective component is needed,so difficulties of design and preparation are reduced. A dielectric multilayer film is applied to the reflective component, and the long wave-pass coating stacks of the structure are designed. To achieve high stopband transmittance and reduce electric field intensity at a wavelength of 1053 nm, an objective function is proposed for designing an optimized coating. The final optimized coating has good spectral characteristics and a high laser-induced damage threshold. A dielectric multilayer film with high reflectance plays an important role in preparing and applying a dielectric multilayer film reflecting cutoff filter-combination device.展开更多
The design,fabrication and performance of narrow-band rugate minus filters are investigated in this paper.A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O_(2))and high(Al_(2)...The design,fabrication and performance of narrow-band rugate minus filters are investigated in this paper.A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O_(2))and high(Al_(2)O_(3))refractive index materials is presented to fabricate a rugate structure.The narrow-band rugate minus filter design and fabrication approaches are discussed in detail.The experimental results,including transmittance spectrum,surface damage test and damage morphology investigated with a scanning electron microscope,demonstrate the high performance of the as-fabricated spatial filter and confirm the feasibility of the fabrication method for narrow-band rugate minus filters.展开更多
Ta2O5/SiO2 and ZrO2/SiO2 high reflecting （HR） coatings are prepared by ion beam sputtering and electron beam evaporation, respectively. The laser-induced damage thresholds （LIDTs） of these samples are investigated...Ta2O5/SiO2 and ZrO2/SiO2 high reflecting （HR） coatings are prepared by ion beam sputtering and electron beam evaporation, respectively. The laser-induced damage thresholds （LIDTs） of these samples are investigated with 2μm femtosecond pulse lasers （80fs, 1kHz）. It is found that the Ta2O5/SiO2 HR coating has a higher capability of laser damage resistance than the ZrO2/SiO2 HR coating in the 2μm femtosecond regime. The scanning electron microscope results show that the damage sites of the ZrO2//SiO2 FIR coating have a relatively porous structure, the loose structure of coatings will provide more sites for water molecules, and the LIDTs of HR coatings will be reduced as a result of the strong water absorption at the wavelength of 2 μm.展开更多
The angular resolutions of the phase-shifted Rugate thin-film filters, the ultra-narrow bandpass filters, and a cutoff filter-combination device are discussed, and the electric field distributions of the filters are c...The angular resolutions of the phase-shifted Rugate thin-film filters, the ultra-narrow bandpass filters, and a cutoff filter-combination device are discussed, and the electric field distributions of the filters are compared. The results show that the three transmitting multi-layer thin-film filters can realize the same angular resolution, but the electric field in the cutoff filter-combination device is the lowest. Because a lower electric-field distribution corresponds to a higher laser-induced damage threshold of the thin films, the cutoff filter-combination device may replace the traditional spatial filters in high power laser systems.展开更多
文摘Chirped mirrors （CMs） are designed and manufactured. The optimized CM provides a group delay dispersion （ODD） of around -60fs^2 and average reflectivity of 99.4% with bandwidth 200 nm at a central wavelength of 800nm. The CM structure consists of 52 layers of alternating high refractive index Ta2O5 and low refractive index SiO2. Measurement results show that the control of CM manufacturing accuracy can meet our requirement through time control with ion beam sputtering. Because the ODD of CMs is highly sensitive to small discrepancies between the layer thickness of calculated design and those of the manufactured mirror, we analyze the error sources which result in thickness errors and refractive index inhomogeneities in film manufacture.
文摘The experiment setup of a reflecting combination device, which has more advantages than a transmitting combination device, is designed in this study. To achieve angular spectrum selectivity, only one type of reflective component is needed,so difficulties of design and preparation are reduced. A dielectric multilayer film is applied to the reflective component, and the long wave-pass coating stacks of the structure are designed. To achieve high stopband transmittance and reduce electric field intensity at a wavelength of 1053 nm, an objective function is proposed for designing an optimized coating. The final optimized coating has good spectral characteristics and a high laser-induced damage threshold. A dielectric multilayer film with high reflectance plays an important role in preparing and applying a dielectric multilayer film reflecting cutoff filter-combination device.
基金Project supported by the Postdoctoral Science Foundation of China(Grant Nos.2016M592528 and 2016M602517)the Natural Science Foundation of Guangdong Province,China(Grant No.2017A030310130)the National Natural Science Foundation of China(Grant No.11705259)
文摘The design,fabrication and performance of narrow-band rugate minus filters are investigated in this paper.A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O_(2))and high(Al_(2)O_(3))refractive index materials is presented to fabricate a rugate structure.The narrow-band rugate minus filter design and fabrication approaches are discussed in detail.The experimental results,including transmittance spectrum,surface damage test and damage morphology investigated with a scanning electron microscope,demonstrate the high performance of the as-fabricated spatial filter and confirm the feasibility of the fabrication method for narrow-band rugate minus filters.
文摘Ta2O5/SiO2 and ZrO2/SiO2 high reflecting （HR） coatings are prepared by ion beam sputtering and electron beam evaporation, respectively. The laser-induced damage thresholds （LIDTs） of these samples are investigated with 2μm femtosecond pulse lasers （80fs, 1kHz）. It is found that the Ta2O5/SiO2 HR coating has a higher capability of laser damage resistance than the ZrO2/SiO2 HR coating in the 2μm femtosecond regime. The scanning electron microscope results show that the damage sites of the ZrO2//SiO2 FIR coating have a relatively porous structure, the loose structure of coatings will provide more sites for water molecules, and the LIDTs of HR coatings will be reduced as a result of the strong water absorption at the wavelength of 2 μm.
文摘The angular resolutions of the phase-shifted Rugate thin-film filters, the ultra-narrow bandpass filters, and a cutoff filter-combination device are discussed, and the electric field distributions of the filters are compared. The results show that the three transmitting multi-layer thin-film filters can realize the same angular resolution, but the electric field in the cutoff filter-combination device is the lowest. Because a lower electric-field distribution corresponds to a higher laser-induced damage threshold of the thin films, the cutoff filter-combination device may replace the traditional spatial filters in high power laser systems.
