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Optical Materials|49 Article(s)
Layered full-color tunable structural colors utilizing Ge2Sb2Se4Te1 chalcogenide phase change material|Editors' Pick
Weijie Chen, Dan Wang, Zexiang He, Zhenzhen Duan, Jian Yang, Ning Wang, Zexiong Hu, Nan Chen, Zhengqian Luo, and Yikun Bu
Ge2Sb2Se4Te1, a newly developed phase change material derived from Ge2Sb2Te5, has garnered significant interest among researchers due to its numerous advantages. Here, its phase change characteristics under the electron beam evaporation method are thoroughly investigated, and a layered tunable color structure is proposed. Based on the low intrinsic absorption of Ge2Sb2Se4Te1 material, it exhibits excellent dynamic tunability along with vivid color appearance including high brightness and high purity. In experiments, five representative colors—red, green, blue, yellow, and purple—were successfully prepared. The peak reflection of these samples averaged 92%, and when heated to 320°C, the temperature at which the phase transition of Ge2Sb2Se4Te1 occurred, reflection loss was barely observed. In addition, after phase transition, the sideband reflection at non-target wavelengths decreased by 30%, bringing high-purity crystalline-state colors and noticeable color changes. Therefore, it is believed that the structural color scheme proposed here will contribute to the development of many fields including smart glasses, artificial retinal devices, high-resolution displays, and beyond. Ge2Sb2Se4Te1, a newly developed phase change material derived from Ge2Sb2Te5, has garnered significant interest among researchers due to its numerous advantages. Here, its phase change characteristics under the electron beam evaporation method are thoroughly investigated, and a layered tunable color structure is proposed. Based on the low intrinsic absorption of Ge2Sb2Se4Te1 material, it exhibits excellent dynamic tunability along with vivid color appearance including high brightness and high purity. In experiments, five representative colors—red, green, blue, yellow, and purple—were successfully prepared. The peak reflection of these samples averaged 92%, and when heated to 320°C, the temperature at which the phase transition of Ge2Sb2Se4Te1 occurred, reflection loss was barely observed. In addition, after phase transition, the sideband reflection at non-target wavelengths decreased by 30%, bringing high-purity crystalline-state colors and noticeable color changes. Therefore, it is believed that the structural color scheme proposed here will contribute to the development of many fields including smart glasses, artificial retinal devices, high-resolution displays, and beyond.
Chinese Optics Letters
- Publication Date: Mar. 19, 2025
- Vol. 23, Issue 3, 031601 (2025)
Optical modulation of photoluminescence in carbon quantum dots using diarylethene molecular photoswitches [Invited]
Kezhou Chen, Xiangyu Meng, Qingxin Luan, Bo Albinsson, Lili Hou, and Tiegen Liu
Modulating photoluminescent (PL) materials is crucial for applications such as super-resolution microscopy. The combination of PL materials and photoswitches can achieve this aim by utilizing isomerization of the photoswitches. Here we report an optically PL switchable system by mixing carbon quantum dots (CQDs) and diarylethene (DAE) molecular photoswitches. The PL on/off states of CQDs, switched with alternating visible and UV light, achieve a PL on/off ratio of ∼500 and stable reversibility over 20 cycles. The mechanism of our design is revealed by PL lifetime measurements, temperature-dependent PL spectroscopy, and density functional theory (DFT) calculations, confirming that efficient static quenching and the inner filter effect between CQDs and closed DAEs are the keys to achieving such outstanding performance. Modulating photoluminescent (PL) materials is crucial for applications such as super-resolution microscopy. The combination of PL materials and photoswitches can achieve this aim by utilizing isomerization of the photoswitches. Here we report an optically PL switchable system by mixing carbon quantum dots (CQDs) and diarylethene (DAE) molecular photoswitches. The PL on/off states of CQDs, switched with alternating visible and UV light, achieve a PL on/off ratio of ∼500 and stable reversibility over 20 cycles. The mechanism of our design is revealed by PL lifetime measurements, temperature-dependent PL spectroscopy, and density functional theory (DFT) calculations, confirming that efficient static quenching and the inner filter effect between CQDs and closed DAEs are the keys to achieving such outstanding performance.
Chinese Optics Letters
- Publication Date: Mar. 10, 2025
- Vol. 23, Issue 2, 021601 (2025)
Light-activated film diffractive optical elements enable diversified optical field modulation
Ning Shen, Honglong Hu, Zhaoyi Wang, Yuxing Zhan, Conglong Yuan, and Zhigang Zheng
We propose a promising method to develop flexible, compact, and tunable light-activated film diffractive optical elements (FDOEs) with exceptional diffraction efficiency, by integrating liquid crystal (LC) geometric phase-based diffractive optical elements (DOEs) with a specifically designed light-activated LC polymer (LCP) film. Arbitrary film bending induced by UV/Vis irradiation is realized through precise mesogens arrangement within the LCP film, enabling 1D and 2D beam steering, as well as dynamic and reversible switching between structured and Gaussian lights after cooperating with the DOE design. Furthermore, remarkable fatigue resistance, solvent resistance, and thermal stability are demonstrated, providing a solid material platform for advanced optical applications. We propose a promising method to develop flexible, compact, and tunable light-activated film diffractive optical elements (FDOEs) with exceptional diffraction efficiency, by integrating liquid crystal (LC) geometric phase-based diffractive optical elements (DOEs) with a specifically designed light-activated LC polymer (LCP) film. Arbitrary film bending induced by UV/Vis irradiation is realized through precise mesogens arrangement within the LCP film, enabling 1D and 2D beam steering, as well as dynamic and reversible switching between structured and Gaussian lights after cooperating with the DOE design. Furthermore, remarkable fatigue resistance, solvent resistance, and thermal stability are demonstrated, providing a solid material platform for advanced optical applications.
Chinese Optics Letters
- Publication Date: Jan. 27, 2025
- Vol. 23, Issue 1, 011602 (2025)
Linear optical characterization of meter-size zinc sulfide polycrystal
Xiaobo Zhao, Kui Wu, Dazhi Lu, Cong Zhang, Haohai Yu, and Huaijin Zhang
Zinc sulfide (ZnS) has promising linear and nonlinear optical properties and has shown important applications in military and modern devices. In this work, coupled with the chemical vapor deposition (CVD) method and hot isostatic pressing (HIP), we successfully grew a high-transmittance and low-absorption-coefficient polycrystalline ZnS with a size of 1 m × 2 m and a thickness of 20 mm. The linear optical properties, including the UV-vis-NIR transmission spectrum, infrared spectrum, and refractive index, were systematically characterized, which shows that the present ZnS polycrystal exhibits a wide transmission range from 0.34 to 15.00 µm, covering two important atmospheric windows. Moreover, its Sellmeier equation was achieved and fitted as a modification of previous studies. According to the refractive index and transmission spectrum, optical loss was calculated to be < 3.5% from 1 to 10 µm. All the results indicate that the present sample has comparable properties with the single crystals and should have potential applications as a functional material. Zinc sulfide (ZnS) has promising linear and nonlinear optical properties and has shown important applications in military and modern devices. In this work, coupled with the chemical vapor deposition (CVD) method and hot isostatic pressing (HIP), we successfully grew a high-transmittance and low-absorption-coefficient polycrystalline ZnS with a size of 1 m × 2 m and a thickness of 20 mm. The linear optical properties, including the UV-vis-NIR transmission spectrum, infrared spectrum, and refractive index, were systematically characterized, which shows that the present ZnS polycrystal exhibits a wide transmission range from 0.34 to 15.00 µm, covering two important atmospheric windows. Moreover, its Sellmeier equation was achieved and fitted as a modification of previous studies. According to the refractive index and transmission spectrum, optical loss was calculated to be < 3.5% from 1 to 10 µm. All the results indicate that the present sample has comparable properties with the single crystals and should have potential applications as a functional material.
Chinese Optics Letters
- Publication Date: Feb. 04, 2025
- Vol. 23, Issue 1, 011601 (2025)
Visible-infrared-terahertz optical modulation of few-layer graphene through lithium intercalation
Ganying Zeng, Zhenyu Fang, Weibao He, Zixuan Wang, Yijie Li, Liantuan Xiao, Suotang Jia, Chengbing Qin, and Renyan Zhang
Optical modulation is significant and ubiquitous to telecommunication technologies, smart windows, and military devices. However, due to the limited tunability of traditional doping, achieving broadband optical property change is a tough problem. Here, we demonstrate a remarkable transformation of optical transmittance in few-layer graphene (FLG) covering the electromagnetic spectra from the visible to the terahertz wave after lithium (Li) intercalation. It results in the transmittance being higher than 90% from the wavelengths of 480 to 1040 nm, and it increases most from 86.4% to 94.1% at 600 nm, reduces from ∼80% to ∼68% in the wavelength range from 2.5 to 11 µm, has ∼20% reduction over a wavelength range from 0.4 to 1.2 THz, and reduces from 97.2% to 68.2% at the wavelength of 1.2 THz. The optical modification of lithiated FLG is attributed to the increase of Fermi energy (Ef) due to the charge transfer from Li to graphene layers. Our results may provide a new strategy for the design of broadband optical modulation devices. Optical modulation is significant and ubiquitous to telecommunication technologies, smart windows, and military devices. However, due to the limited tunability of traditional doping, achieving broadband optical property change is a tough problem. Here, we demonstrate a remarkable transformation of optical transmittance in few-layer graphene (FLG) covering the electromagnetic spectra from the visible to the terahertz wave after lithium (Li) intercalation. It results in the transmittance being higher than 90% from the wavelengths of 480 to 1040 nm, and it increases most from 86.4% to 94.1% at 600 nm, reduces from ∼80% to ∼68% in the wavelength range from 2.5 to 11 µm, has ∼20% reduction over a wavelength range from 0.4 to 1.2 THz, and reduces from 97.2% to 68.2% at the wavelength of 1.2 THz. The optical modification of lithiated FLG is attributed to the increase of Fermi energy (Ef) due to the charge transfer from Li to graphene layers. Our results may provide a new strategy for the design of broadband optical modulation devices.
Chinese Optics Letters
- Publication Date: Sep. 13, 2024
- Vol. 22, Issue 9, 091601 (2024)
Slicing of large-size single crystals by ultrafast laser with external stress assistance
Lifeng Wang, Lili Liu, Yinan Wang, Xun Li, Chenchen Li, and Ming Li
The existing single-crystal slicing techniques result in significant material wastage and elevate the production cost of premium-quality thin slices of crystals. Here we report (for the first time, to our knowledge) an approach for vertical slicing of large-size single-crystal gain materials by ultrafast laser. By employing aberration correction techniques, the optimization of the optical field distribution within the high-refractive-index crystal enables the achievement of a continuous laser-modified layer with a thickness of less than 10 µm, oriented perpendicular to the direction of the laser direction. The compressed focal spot facilitates crack initiation, enabling propagation under external forces, ultimately achieving the successful slicing of a Φ12 mm crystal. The surface roughness of the sliced Yb:YAG is less than 2.5 µm. The results illustrate the potential of low-loss slicing strategy for single-crystal fabrication and pave the way for the future development of thin disk lasers. The existing single-crystal slicing techniques result in significant material wastage and elevate the production cost of premium-quality thin slices of crystals. Here we report (for the first time, to our knowledge) an approach for vertical slicing of large-size single-crystal gain materials by ultrafast laser. By employing aberration correction techniques, the optimization of the optical field distribution within the high-refractive-index crystal enables the achievement of a continuous laser-modified layer with a thickness of less than 10 µm, oriented perpendicular to the direction of the laser direction. The compressed focal spot facilitates crack initiation, enabling propagation under external forces, ultimately achieving the successful slicing of a Φ12 mm crystal. The surface roughness of the sliced Yb:YAG is less than 2.5 µm. The results illustrate the potential of low-loss slicing strategy for single-crystal fabrication and pave the way for the future development of thin disk lasers.
Chinese Optics Letters
- Publication Date: Aug. 21, 2024
- Vol. 22, Issue 8, 081601 (2024)
Gd3Al3Ga2O12:Ce3+, Yb3+ fluorescent ceramic with highly increased trap density for optical information storage
Jiaocheng Yin, Renjie Jiang, Junwei Zhang, Qiao Hu, Miao Zhao, Xiaoxia Wang, Anlian Pan, and Hao Ruan
Electron-trapping materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage (OIS). In this work, Gd3Al3Ga2O12:Ce3+, Yb3+ fluorescent ceramics, were developed using air and vacuum sintering technology. By co-doping Ce3+ and Yb3+, the trap density was significantly increased by 7.5 times compared to samples containing only Ce3+. Vacuum annealing further enhanced trap density by 1.6 times compared to samples sintered solely in air, while generating deep traps (1.44 eV), making Gd3Al3Ga2O12:Ce3+, Yb3+ an excellent OIS medium. This work is expected to facilitate the development of OIS materials. Electron-trapping materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage (OIS). In this work, Gd3Al3Ga2O12:Ce3+, Yb3+ fluorescent ceramics, were developed using air and vacuum sintering technology. By co-doping Ce3+ and Yb3+, the trap density was significantly increased by 7.5 times compared to samples containing only Ce3+. Vacuum annealing further enhanced trap density by 1.6 times compared to samples sintered solely in air, while generating deep traps (1.44 eV), making Gd3Al3Ga2O12:Ce3+, Yb3+ an excellent OIS medium. This work is expected to facilitate the development of OIS materials.
Chinese Optics Letters
- Publication Date: Jul. 10, 2024
- Vol. 22, Issue 7, 071601 (2024)
Optical properties of stacked liquid crystal superstructures with opposite chirality [Invited]|Editors' Pick
Lin Zhu, Yiheng Zhang, Shijun Ge, Peng Chen, and Yanqing Lu
Cholesteric liquid crystal (CLC) has been widely used in flat optical elements due to the Pancharatnam–Berry (PB) phase modulation. In order to achieve PB phase modulation for both circular polarizations, it is natural to come up with stacking CLCs with opposite chirality. Here, various optical properties of diverse CLC stacking structures are systematically investigated by numerical calculations. With the thickness of the CLC sublayers becoming smaller, the reflection bandgap splits into three main parts, and the rotatory dispersion gradually becomes negligible. Vector beams provide a more intuitive verification. These results provide theoretical guidance for future studies on stacked chiral anisotropic media. Cholesteric liquid crystal (CLC) has been widely used in flat optical elements due to the Pancharatnam–Berry (PB) phase modulation. In order to achieve PB phase modulation for both circular polarizations, it is natural to come up with stacking CLCs with opposite chirality. Here, various optical properties of diverse CLC stacking structures are systematically investigated by numerical calculations. With the thickness of the CLC sublayers becoming smaller, the reflection bandgap splits into three main parts, and the rotatory dispersion gradually becomes negligible. Vector beams provide a more intuitive verification. These results provide theoretical guidance for future studies on stacked chiral anisotropic media.
Chinese Optics Letters
- Publication Date: Jun. 20, 2024
- Vol. 22, Issue 6, 061601 (2024)
Saturable absorption and visible pulse modulation of few-layer topological nodal-line semimetal HfGeTe
Qiming Zhao, Shouyan Zhang, Shuxian Wang, Gang Wang, Haohai Yu, and Huaijin Zhang
Topological nodal-line semimetals attract growing research attention in the photonic and optoelectronic fields due to their unique topological energy-level bands and fascinating nonlinear optical responses. Here, to the best of our knowledge, we first report the saturable absorption property of topological nodal-line semimetal HfGeTe and the related pulse modulation in passively Q-switched visible lasers. Few-layer HfGeTe demonstrates outstanding saturable absorption properties in the visible-light band, yielding the saturation intensities of 7.88, 12.66, and 6.64 µJ/cm2 at 515, 640, and 720 nm, respectively. Based on an as-prepared few-layer HfGeTe optical switch and a Pr:LiYF4 gain medium, Q-switched visible lasers are also successfully achieved at 522, 640, and 720 nm. The minimum pulse widths of the green, red, and deep-red pulsed lasers are 150, 125.5, and 420 ns, respectively. Especially for the green and red pulsed laser, the obtained pulse width is smaller than those of the low-dimensional layered materials. Our work sheds light on the application potential of topological nodal-line semimetals in the generation of visible pulsed lasers. Topological nodal-line semimetals attract growing research attention in the photonic and optoelectronic fields due to their unique topological energy-level bands and fascinating nonlinear optical responses. Here, to the best of our knowledge, we first report the saturable absorption property of topological nodal-line semimetal HfGeTe and the related pulse modulation in passively Q-switched visible lasers. Few-layer HfGeTe demonstrates outstanding saturable absorption properties in the visible-light band, yielding the saturation intensities of 7.88, 12.66, and 6.64 µJ/cm2 at 515, 640, and 720 nm, respectively. Based on an as-prepared few-layer HfGeTe optical switch and a Pr:LiYF4 gain medium, Q-switched visible lasers are also successfully achieved at 522, 640, and 720 nm. The minimum pulse widths of the green, red, and deep-red pulsed lasers are 150, 125.5, and 420 ns, respectively. Especially for the green and red pulsed laser, the obtained pulse width is smaller than those of the low-dimensional layered materials. Our work sheds light on the application potential of topological nodal-line semimetals in the generation of visible pulsed lasers.
Chinese Optics Letters
- Publication Date: Mar. 25, 2024
- Vol. 22, Issue 3, 031601 (2024)
Flexible one-dimensional photonic crystal films composed of chalcogenide glass and water-soluble polymer for curvature sensing
Xinyu Chen, Zhangcheng Li, Ruolan Zhao, Yu He, Yue He, Zhi Liang, Guangming Tao, and Chong Hou
Curvature sensing plays an important role in structural health monitoring, damage detection, real-time shape control, modification, etc. Developing curvature sensors with large measurement ranges, high sensitivity, and linearity remains a major challenge. In this study, a curvature sensor based on flexible one-dimensional photonic crystal (1D-PC) films was proposed. The flexible 1D-PC films composed of dense chalcogenide glass and water-soluble polymer materials were fabricated by solution processing. The flexible 1D-PC film curvature sensor has a wide measurement range of 33–133 m-1 and a maximum sensitivity of 0.26 nm/m-1. The shift of the transmission peak varies approximately linearly with the curvature in the entire measurement range. This kind of 1D-PC film curvature sensor provides a new idea for curvature sensing and measurement. Curvature sensing plays an important role in structural health monitoring, damage detection, real-time shape control, modification, etc. Developing curvature sensors with large measurement ranges, high sensitivity, and linearity remains a major challenge. In this study, a curvature sensor based on flexible one-dimensional photonic crystal (1D-PC) films was proposed. The flexible 1D-PC films composed of dense chalcogenide glass and water-soluble polymer materials were fabricated by solution processing. The flexible 1D-PC film curvature sensor has a wide measurement range of 33–133 m-1 and a maximum sensitivity of 0.26 nm/m-1. The shift of the transmission peak varies approximately linearly with the curvature in the entire measurement range. This kind of 1D-PC film curvature sensor provides a new idea for curvature sensing and measurement.
Chinese Optics Letters
- Publication Date: Feb. 29, 2024
- Vol. 22, Issue 2, 021601 (2024)
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