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Optical Materials|40 Article(s)
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)
Toroidal dipole response in rectangular waveguide: used to generate vector beams and vector vortex beams
Hao Luo, Cong Chen, Peng Gao, Yue Feng, Ziyan Ren, Yujia Qiao, and Hai Liu
Toroidal multipole is a special current distribution that has many different characteristics from electric multipole and magnetic multipole distributions. Because of its special properties, the toroidal dipole is a research hotspot in the field of metamaterials and nanophotonics. However, the low scattering of the toroidal dipole moment makes its excitation a challenging task. At present, there are relatively few studies on its specific engineering applications. In this paper, by slotting in the rectangular cavity, the excitation of an equivalent toroidal dipole is successfully achieved over a wide frequency range of 53–58 GHz. Results indicate that under the action of the toroidal dipole, the TE10 mode electromagnetic waves transmitted in the rectangular waveguide are converted into vector beams and are radiated outwards. Further adjusting the spatial distribution of the magnetic dipoles in the toroidal dipoles yields results that indicate that the resonance mode in the slot is still dominated by the magnetic toroidal dipole moment, and the electromagnetic waves radiating outward are vortex beams carrying vector polarization. The scattered energy of each dipole moment inside the antenna is calculated. This calculation verifies that the mass of the vector beam and vector vortex beam is closely related to the toroidal dipole supported by this antenna. The proposed structure can be applied to explorations in vortex filtering, in photon entanglement, and in the photonic spin Hall effect. Toroidal multipole is a special current distribution that has many different characteristics from electric multipole and magnetic multipole distributions. Because of its special properties, the toroidal dipole is a research hotspot in the field of metamaterials and nanophotonics. However, the low scattering of the toroidal dipole moment makes its excitation a challenging task. At present, there are relatively few studies on its specific engineering applications. In this paper, by slotting in the rectangular cavity, the excitation of an equivalent toroidal dipole is successfully achieved over a wide frequency range of 53–58 GHz. Results indicate that under the action of the toroidal dipole, the TE10 mode electromagnetic waves transmitted in the rectangular waveguide are converted into vector beams and are radiated outwards. Further adjusting the spatial distribution of the magnetic dipoles in the toroidal dipoles yields results that indicate that the resonance mode in the slot is still dominated by the magnetic toroidal dipole moment, and the electromagnetic waves radiating outward are vortex beams carrying vector polarization. The scattered energy of each dipole moment inside the antenna is calculated. This calculation verifies that the mass of the vector beam and vector vortex beam is closely related to the toroidal dipole supported by this antenna. The proposed structure can be applied to explorations in vortex filtering, in photon entanglement, and in the photonic spin Hall effect.
Chinese Optics Letters
- Publication Date: Jan. 22, 2024
- Vol. 22, Issue 1, 011601 (2024)
Tb3+-doped borosilicate glass scintillators for high-resolution X-ray imaging
Wenjun Huang, Junyu Chen, Yi Li, Yueyue Wu, Lianjie Li, Liping Chen, and Hai Guo
Scintillators are the vital component in X-ray perspective image technology that is applied in medical imaging, industrial nondestructive testing, and safety testing. But the high cost and small size of single-crystal commercialized scintillators limit their practical application. Here, a series of Tb3+-doped borosilicate glass (BSG) scintillators with big production size, low cost, and high spatial resolution are designed and fabricated. The structural, photoluminescent, and scintillant properties are systematically investigated. Benefiting from excellent transmittance (87% at 600 nm), high interquantum efficiency (60.7%), and high X-ray excited luminescence (217% of Bi4Ge3O12), the optimal sample shows superhigh spatial resolution (exceeding 20 lp/mm). This research suggests that Tb3+-doped BSG scintillators have potential applications in the static X-ray imaging field. Scintillators are the vital component in X-ray perspective image technology that is applied in medical imaging, industrial nondestructive testing, and safety testing. But the high cost and small size of single-crystal commercialized scintillators limit their practical application. Here, a series of Tb3+-doped borosilicate glass (BSG) scintillators with big production size, low cost, and high spatial resolution are designed and fabricated. The structural, photoluminescent, and scintillant properties are systematically investigated. Benefiting from excellent transmittance (87% at 600 nm), high interquantum efficiency (60.7%), and high X-ray excited luminescence (217% of Bi4Ge3O12), the optimal sample shows superhigh spatial resolution (exceeding 20 lp/mm). This research suggests that Tb3+-doped BSG scintillators have potential applications in the static X-ray imaging field.
Chinese Optics Letters
- Publication Date: Jul. 25, 2023
- Vol. 21, Issue 7, 071601 (2023)
Environmentally stable, spectral-shape-controllable, GHz femtosecond Yb-doped fiber laser
Kefeng Chen, Lina Gan, Yingge Tao, Weilin Shao, Wei Yu, Haowei Lin, Zhiping Cai, and Huihui Cheng
We demonstrate an all-polarization-maintaining (PM) passively mode-locked Yb3+-doped fiber laser (YDFL) with a fundamental repetition rate of 1.3 GHz. The optical spectra of a linearly polarized soliton exhibit different shapes by rotating the fast axis of the fiber optical pigtail of a dispersive dielectric mirror. The oscillator provides a series of laser performance, such as a threshold pump power for continuous wave laser oscillation of 3.1 mW, an optical-to-optical efficiency for mode-locking of 29%, and an integrated relative intensity noise of 0.08%. To the best of our knowledge, this is the first report of >1 GHz ultrafast all-fiber YDFL with PM architecture. We demonstrate an all-polarization-maintaining (PM) passively mode-locked Yb3+-doped fiber laser (YDFL) with a fundamental repetition rate of 1.3 GHz. The optical spectra of a linearly polarized soliton exhibit different shapes by rotating the fast axis of the fiber optical pigtail of a dispersive dielectric mirror. The oscillator provides a series of laser performance, such as a threshold pump power for continuous wave laser oscillation of 3.1 mW, an optical-to-optical efficiency for mode-locking of 29%, and an integrated relative intensity noise of 0.08%. To the best of our knowledge, this is the first report of >1 GHz ultrafast all-fiber YDFL with PM architecture.
Chinese Optics Letters
- Publication Date: Jun. 06, 2023
- Vol. 21, Issue 6, 061601 (2023)
Solar-blind avalanche photodetector based on epitaxial Ga2O3/La0.8Ca0.2MnO3 pn heterojunction with ultrahigh gain
Ning Li, Qingyi Zhang, Yongtao Yang, Yuanjun Tang, Tao Zhang, Jiaying Shen, Yuehui Wang, Fan Zhang, Yang Zhang, and Zhenping Wu
Ga2O3-based avalanche photodetectors (APDs) have gained increasing attention because of their excellent photoelectric conversion capability in the UV solar-blind region. Integrating high-quality epitaxial Ga2O3 with p-type semiconductor remains an open challenge associated with the integration difficulty on alleviating its defects and dislocations. Herein, we construct an APD consisting of epitaxial β-Ga2O3/La0.8Ca0.2MnO3 heterostructure. The pn junction APDs exhibit a high responsivity of 568 A/W as well as an enhanced avalanche gain of up to 3.0×105 at a reverse bias voltage of 37.9 V. The integration capability demonstrated in this work provides exciting opportunities for further development of high-performance Ga2O3-based electronics and optoelectronics. Ga2O3-based avalanche photodetectors (APDs) have gained increasing attention because of their excellent photoelectric conversion capability in the UV solar-blind region. Integrating high-quality epitaxial Ga2O3 with p-type semiconductor remains an open challenge associated with the integration difficulty on alleviating its defects and dislocations. Herein, we construct an APD consisting of epitaxial β-Ga2O3/La0.8Ca0.2MnO3 heterostructure. The pn junction APDs exhibit a high responsivity of 568 A/W as well as an enhanced avalanche gain of up to 3.0×105 at a reverse bias voltage of 37.9 V. The integration capability demonstrated in this work provides exciting opportunities for further development of high-performance Ga2O3-based electronics and optoelectronics.
Chinese Optics Letters
- Publication Date: Apr. 06, 2023
- Vol. 21, Issue 5, 051604 (2023)
Enhanced near-infrared light-induced photoresponse via transition of monocrystalline phase and surface reconstruction
Hong Jia, Hongming Jiang, Yuping Zhang, Shuxu Hua, Qing Liu, Yuquan Yuan, Yanfei Hu, Feng Peng, and Xiaofeng Liu
Rare-earth-doped upconversion (UC) materials are ideal candidates for solar photovoltaic conversion and NIR response devices due to their unique spectral conversion properties. However, their low efficiency remains a tremendous challenge for practical applications. Here, we constructed an efficient NIR light-responsive device by coating a Si-photoresistor with a transparent gel consisting of UC powders and an organic polymer matrix. We show that reasonable introduction of alkali metal ions (Na+, K+, and Cs+) into the lattice of UC crystals results in the improvement of photoelectricity conversion efficiency, due to the high crystallinity and surface reconstruction caused by alkali metal ion doping. Rare-earth-doped upconversion (UC) materials are ideal candidates for solar photovoltaic conversion and NIR response devices due to their unique spectral conversion properties. However, their low efficiency remains a tremendous challenge for practical applications. Here, we constructed an efficient NIR light-responsive device by coating a Si-photoresistor with a transparent gel consisting of UC powders and an organic polymer matrix. We show that reasonable introduction of alkali metal ions (Na+, K+, and Cs+) into the lattice of UC crystals results in the improvement of photoelectricity conversion efficiency, due to the high crystallinity and surface reconstruction caused by alkali metal ion doping.
Chinese Optics Letters
- Publication Date: Apr. 13, 2023
- Vol. 21, Issue 5, 051603 (2023)
Effective warm white-light emission with Dy:YAlO3 single crystal
Cong Zhang, Yunru Chen, Shihui Ma, Honghua Fan, Yonggui Yu, Zhanggui Hu, Ning Ye, Jiyang Wang, and Yicheng Wu
Dysprosium-doped orthorhombic yttrium aluminate (Dy:YAlO3 or Dy:YAP) single crystals were grown by the Czochralski method with a size of Φ43 mm×150 mm. Based on the measurements of spectra and theoretical analysis, the white-light emission was investigated with different doping concentrations. The optimal white emission was achieved at Dy3+ doping concentration of 1.0% under 450 nm excitation. Combining with residual pumping light, the white-light output was successfully obtained with Commission Internationale de l´Eclairage (CIE) coordinates x=0.3797, y=0.3685, the color temperature of 4000 K, and the largest fluorescence quantum yield of 46.9%. With the development of the GaN laser diode, the Dy:YAP single crystal has proven applicable in white-light-emitting diodes. Dysprosium-doped orthorhombic yttrium aluminate (Dy:YAlO3 or Dy:YAP) single crystals were grown by the Czochralski method with a size of Φ43 mm×150 mm. Based on the measurements of spectra and theoretical analysis, the white-light emission was investigated with different doping concentrations. The optimal white emission was achieved at Dy3+ doping concentration of 1.0% under 450 nm excitation. Combining with residual pumping light, the white-light output was successfully obtained with Commission Internationale de l´Eclairage (CIE) coordinates x=0.3797, y=0.3685, the color temperature of 4000 K, and the largest fluorescence quantum yield of 46.9%. With the development of the GaN laser diode, the Dy:YAP single crystal has proven applicable in white-light-emitting diodes.
Chinese Optics Letters
- Publication Date: May. 10, 2023
- Vol. 21, Issue 5, 051602 (2023)
Highly efficient, tunable, ultrabroadband NIR photoemission from Bi-doped nitridated germanate glasses toward all-band amplification in optical communication
Fuguang Chen, Zhi Chen, Jianrong Qiu, Shuai Zhang, and Zhijun Ma
Bismuth (Bi)-doped near-infared (NIR) glass that can cover the entire optical communication window (850, 1310, and 1550 nm) has become the subject of extensive research for developing photonic devices, particularly, tunable fiber lasers and ultrabroadband optical amplifiers. However, the realization of highly efficient NIR luminescence from Bi-doped glass is still full of challenges. Notably, due to the co-existence of multiple Bi NIR centers in the glass, the origin of newly generated Bi NIR emission peaks at ∼930 and ∼1520 nm is still controversial. Here, we report a new Bi-doped nitridated germanate glass with tunable ultrabroadband NIR emission (850–1700 nm) and high external quantum efficiency (EQE) of ∼50%. A series of studies, including spectral analysis, nuclear magnetic resonance (NMR), and others, provide powerful evidence for the mechanism of luminescence enhancement and tunability, and make reasonable inferences about the origin of the new emission bands at ∼930 and ∼1520 nm. We believe that the results discussed above would enrich our understanding about multiple Bi NIR emission behaviors and contribute to the design and fabrication of highly efficient Bi-doped ultrabroadband wavelength-tunable optical glass fiber amplifiers and lasers in the future. Bismuth (Bi)-doped near-infared (NIR) glass that can cover the entire optical communication window (850, 1310, and 1550 nm) has become the subject of extensive research for developing photonic devices, particularly, tunable fiber lasers and ultrabroadband optical amplifiers. However, the realization of highly efficient NIR luminescence from Bi-doped glass is still full of challenges. Notably, due to the co-existence of multiple Bi NIR centers in the glass, the origin of newly generated Bi NIR emission peaks at ∼930 and ∼1520 nm is still controversial. Here, we report a new Bi-doped nitridated germanate glass with tunable ultrabroadband NIR emission (850–1700 nm) and high external quantum efficiency (EQE) of ∼50%. A series of studies, including spectral analysis, nuclear magnetic resonance (NMR), and others, provide powerful evidence for the mechanism of luminescence enhancement and tunability, and make reasonable inferences about the origin of the new emission bands at ∼930 and ∼1520 nm. We believe that the results discussed above would enrich our understanding about multiple Bi NIR emission behaviors and contribute to the design and fabrication of highly efficient Bi-doped ultrabroadband wavelength-tunable optical glass fiber amplifiers and lasers in the future.
Chinese Optics Letters
- Publication Date: May. 11, 2023
- Vol. 21, Issue 5, 051601 (2023)
Optical and electrical properties of Sb-doped β-Ga2O3 crystals grown by OFZ method
Baizhong Li, Pengkun Li, Lu Zhang, Ruifeng Tian, Qinglin Sai, Mingyan Pan, Bin Wang, Duanyang Chen, Youchen Liu, Changtai Xia, and Hongji Qi
Sb-doped β-Ga2O3 crystals were grown using the optical floating zone (OFZ) method. X-ray diffraction data and X-ray rocking curves were obtained, and the results revealed that the Sb-doped single crystals were of high quality. Raman spectra revealed that Sb substituted Ga mainly in the octahedral lattice. The carrier concentration of the Sb-doped single crystals increased from 9.55×1016 to 8.10×1018 cm-3, the electronic mobility depicted a decreasing trend from 153.1 to 108.7 cm2 ·V-1 ·s-1, and the electrical resistivity varied from 0.603 to 0.017 Ω·cm with the increasing Sb doping concentration. The un-doped and Sb-doped β-Ga2O3 crystals exhibited good light transmittance in the visible region; however, the evident decrease in the infrared region was caused by increase in the carrier concentration. The Sb-doped β-Ga2O3 single crystals had high transmittance in the UV region as well, and the cutoff edge appeared at 258 nm. Sb-doped β-Ga2O3 crystals were grown using the optical floating zone (OFZ) method. X-ray diffraction data and X-ray rocking curves were obtained, and the results revealed that the Sb-doped single crystals were of high quality. Raman spectra revealed that Sb substituted Ga mainly in the octahedral lattice. The carrier concentration of the Sb-doped single crystals increased from 9.55×1016 to 8.10×1018 cm-3, the electronic mobility depicted a decreasing trend from 153.1 to 108.7 cm2 ·V-1 ·s-1, and the electrical resistivity varied from 0.603 to 0.017 Ω·cm with the increasing Sb doping concentration. The un-doped and Sb-doped β-Ga2O3 crystals exhibited good light transmittance in the visible region; however, the evident decrease in the infrared region was caused by increase in the carrier concentration. The Sb-doped β-Ga2O3 single crystals had high transmittance in the UV region as well, and the cutoff edge appeared at 258 nm.
Chinese Optics Letters
- Publication Date: Apr. 10, 2023
- Vol. 21, Issue 4, 041605 (2023)
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