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Physical Optics|55 Article(s)
Optical microcavity gyroscope assisted by mechanical modes in exceptional surfaces
Ranran Xie, Xueqing Cui, Zhuoqun Wang, Ruyi Xia, Yuechen Jia, and Feng Chen
Optical gyroscopes in microcavity platforms have attracted much attention for their vast applications. For Sagnac effect enhancement, the exceptional surface (ES) concept holds the potential to stabilize exceptional points (EPs), allowing for EP splitting amplification and robustness in sensors. We propose a new optical microcavity gyroscope near the ES. Under the mechanical mode assistance, theoretical analysis reveals its prominent advantages compared with conventional gyroscopes, especially achieving higher levels for extremely low rotational speeds. This breakthrough opens possibilities in high-precision angular velocity measurement, facilitating the development of more accurate and stable sensor technologies. Optical gyroscopes in microcavity platforms have attracted much attention for their vast applications. For Sagnac effect enhancement, the exceptional surface (ES) concept holds the potential to stabilize exceptional points (EPs), allowing for EP splitting amplification and robustness in sensors. We propose a new optical microcavity gyroscope near the ES. Under the mechanical mode assistance, theoretical analysis reveals its prominent advantages compared with conventional gyroscopes, especially achieving higher levels for extremely low rotational speeds. This breakthrough opens possibilities in high-precision angular velocity measurement, facilitating the development of more accurate and stable sensor technologies.
Chinese Optics Letters
- Publication Date: Mar. 20, 2025
- Vol. 23, Issue 3, 032601 (2025)
High robustness, billion Q packaged microcavity devices for soliton microcombs|Editors' Pick
Fangxing Zhang, Shengnan Huangfu, Shengqiang Ji, Yanjie Bai, Xuanyi Zhang, Zijing Cai, Tinglan Chen, Bo Ni, Bowen Ruan, and Jialüe Sun
The exceptional temporal and spatial photon confinement properties of whispering gallery mode (WGM) microcavities render them ideally suitable for nonlinear frequency conversion. Here, we present a reliable packaged microcavity device with vibration isolation, air tightness, temperature adaptability, and quality factors greater than 2 billion that can serve as a compact and stable platform for soliton optical comb generation. Low-noise soliton combs can be initiated with a repetition rate of 24.98 GHz at wavelengths near 1550 nm with 4 mW threshold power. Our work provides innovative solutions for investigating and manufacturing miniature, economical, and robust microcomb devices. The exceptional temporal and spatial photon confinement properties of whispering gallery mode (WGM) microcavities render them ideally suitable for nonlinear frequency conversion. Here, we present a reliable packaged microcavity device with vibration isolation, air tightness, temperature adaptability, and quality factors greater than 2 billion that can serve as a compact and stable platform for soliton optical comb generation. Low-noise soliton combs can be initiated with a repetition rate of 24.98 GHz at wavelengths near 1550 nm with 4 mW threshold power. Our work provides innovative solutions for investigating and manufacturing miniature, economical, and robust microcomb devices.
Chinese Optics Letters
- Publication Date: Feb. 19, 2025
- Vol. 23, Issue 2, 022601 (2025)
Enhanced reflection laser protection thin films compatible with visible light stealth
Zexiang He, Zexiong Hu, Jian Yang, Weijie Chen, Zhenzhen Duan, Ning Wang, Dan Wang, Xiaotan Ji, Nan Chen, Zhengqian Luo, and Yikun Bu
For bicolor regulation in laser protection compatible with visible light stealth, a metal–dielectric–enhanced reflection asymmetric Fabry–Perot structure is proposed that has high reflectance at the laser wavelength and the color control of the visible spectrum. The six-layer reflection enhancement unit is composed of an Al metal mirror, SiO2, Ta2O5, and an ultrathin Nb metal layer. The synergistic relationship between the background color and laser wavelength reflectance was analyzed and simulated. Six different colors from blue to red with high reflectance at 1064 nm laser wavelength up to 97.84% were prepared. The thin films can withstand 2535 W cm-2 power density continuous irradiation for 60 s without being destroyed. Moreover, a symmetrical structure presents the spectrum consistency from both directions, which makes the potential to be applied to the laser protective coatings. The blue symmetrical microreflector sample was prepared and sprayed on the nonplanar models to demonstrate the actual application effect. This simple and efficient scheme provides an innovative technical approach in the field of surface laser protection. For bicolor regulation in laser protection compatible with visible light stealth, a metal–dielectric–enhanced reflection asymmetric Fabry–Perot structure is proposed that has high reflectance at the laser wavelength and the color control of the visible spectrum. The six-layer reflection enhancement unit is composed of an Al metal mirror, SiO2, Ta2O5, and an ultrathin Nb metal layer. The synergistic relationship between the background color and laser wavelength reflectance was analyzed and simulated. Six different colors from blue to red with high reflectance at 1064 nm laser wavelength up to 97.84% were prepared. The thin films can withstand 2535 W cm-2 power density continuous irradiation for 60 s without being destroyed. Moreover, a symmetrical structure presents the spectrum consistency from both directions, which makes the potential to be applied to the laser protective coatings. The blue symmetrical microreflector sample was prepared and sprayed on the nonplanar models to demonstrate the actual application effect. This simple and efficient scheme provides an innovative technical approach in the field of surface laser protection.
Chinese Optics Letters
- Publication Date: Feb. 18, 2025
- Vol. 23, Issue 1, 012602 (2025)
White-light cavity and mode splitting effect in a three-turn lossy microfiber coil resonator
Feilin Zhang, Xiyuan Chen, Yulu Zhong, Qixuan Li, and Mengmeng Sha
Under a specified loss condition, the resonant mode in a three-turn lossy microfiber coil resonator exhibits periodic evolution among normal resonance, white-light cavity effect, and resonance mode splitting in response to alterations in the phase shift and coupling state. It exhibits normal resonance when the coupling state exceeds a threshold with specific loss. The white-light cavity effect is activated when the coupling state matches loss. The resonant phase bifurcates as the coupling state falls below the threshold. The excitation conditions for each resonant mode have been derived, and the critical coupling conditions exist for both normal resonance and mode splitting in the case of relatively small losses. Under a specified loss condition, the resonant mode in a three-turn lossy microfiber coil resonator exhibits periodic evolution among normal resonance, white-light cavity effect, and resonance mode splitting in response to alterations in the phase shift and coupling state. It exhibits normal resonance when the coupling state exceeds a threshold with specific loss. The white-light cavity effect is activated when the coupling state matches loss. The resonant phase bifurcates as the coupling state falls below the threshold. The excitation conditions for each resonant mode have been derived, and the critical coupling conditions exist for both normal resonance and mode splitting in the case of relatively small losses.
Chinese Optics Letters
- Publication Date: Feb. 04, 2025
- Vol. 23, Issue 1, 012601 (2025)
Wide-color-gamut, high-purity, and high-brightness thin film structural colors based on modified Fano resonant structure
Weijie Chen, Zexiang He, Zhenzhen Duan, Jian Yang, Ning Wang, Dan Wang, Zexiong Hu, Nan Chen, Zhengqian Luo, and Yikun Bu
Recently, the Fano resonance has played an increasingly important role in improving the color performance of structural colors. In this study, we further elucidate the asymmetric spectral shape generated by Fano resonance from a phase perspective and explore four distinct continuum state structures. By integrating the proposed cavity-like structure with a metal–dielectric–metal discrete state, multilayered thin-film structural colors with minimal background reflection, as low as 8%, were successfully achieved. The reflection peak of this structure exhibits a bandwidth of approximately 50 nm and reaches up to 80%, indicating heightened saturation and color brightness. Moreover, by adjusting the thickness, we effortlessly obtained a broader color gamut compared to Adobe RGB (45.2%), covering 56.7% of the CIE color space. Even adjusting a single layer can achieve a color gamut of 47.1%. In experiments, by deliberately choosing low oxygen-dependent materials, excellent RGB colors with high brightness and in high consistency with simulation results were successfully achieved. Therefore, the scheme’s simple process for structural color creation, along with its excellent color performance and the ability to effectively replicate simulation characteristics makes it highly valuable in fields like anticounterfeiting, decoration, display devices, and solar cell panels. Recently, the Fano resonance has played an increasingly important role in improving the color performance of structural colors. In this study, we further elucidate the asymmetric spectral shape generated by Fano resonance from a phase perspective and explore four distinct continuum state structures. By integrating the proposed cavity-like structure with a metal–dielectric–metal discrete state, multilayered thin-film structural colors with minimal background reflection, as low as 8%, were successfully achieved. The reflection peak of this structure exhibits a bandwidth of approximately 50 nm and reaches up to 80%, indicating heightened saturation and color brightness. Moreover, by adjusting the thickness, we effortlessly obtained a broader color gamut compared to Adobe RGB (45.2%), covering 56.7% of the CIE color space. Even adjusting a single layer can achieve a color gamut of 47.1%. In experiments, by deliberately choosing low oxygen-dependent materials, excellent RGB colors with high brightness and in high consistency with simulation results were successfully achieved. Therefore, the scheme’s simple process for structural color creation, along with its excellent color performance and the ability to effectively replicate simulation characteristics makes it highly valuable in fields like anticounterfeiting, decoration, display devices, and solar cell panels.
Chinese Optics Letters
- Publication Date: Aug. 21, 2024
- Vol. 22, Issue 8, 082601 (2024)
Single-photon frequency-modulated continuous-wave Lidar based on quantum compressed sensing
Liu Yang, Hongqi Niu, Shuxiao Wu, Jianyong Hu, Mingyong Jing, Zhixing Qiao, Changgang Yang, Guofeng Zhang, Chengbing Qin, Ruiyun Chen, Liantuan Xiao, and Suotang Jia
Frequency-modulated continuous-wave (FMCW) Lidar has the characteristics of high-ranging accuracy, noise immunity, and synchronous speed measurement, which makes it a candidate for the next generation of vehicle Lidar. In this work, an FMCW Lidar working at the single-photon level is demonstrated based on quantum compressed sensing, and the target distance is recovered from the sparse photon detection, in which the detection sensitivity, bandwidth, and compression ratio are improved significantly. Our Lidar system can achieve 3 GHz bandwidth detection at photon count rates of a few thousand, making ultra-long-distance FMCW Lidar possible. Frequency-modulated continuous-wave (FMCW) Lidar has the characteristics of high-ranging accuracy, noise immunity, and synchronous speed measurement, which makes it a candidate for the next generation of vehicle Lidar. In this work, an FMCW Lidar working at the single-photon level is demonstrated based on quantum compressed sensing, and the target distance is recovered from the sparse photon detection, in which the detection sensitivity, bandwidth, and compression ratio are improved significantly. Our Lidar system can achieve 3 GHz bandwidth detection at photon count rates of a few thousand, making ultra-long-distance FMCW Lidar possible.
Chinese Optics Letters
- Publication Date: Jul. 17, 2024
- Vol. 22, Issue 7, 072602 (2024)
Non-diffracting integer-order and half-integer-order carpet beams obtained by even-type sinusoidal amplitude radial gratings
Yefeng Liu, Huiqing Li, Rijian Chen, Changjiang Fan, Yile Shi, and Zhijun Ren
In this work, we introduce a kind of new structured radial grating, which is named the even-type sinusoidal amplitude radial (ETASR) grating. Based on diffraction theory and the principle of stationary phase, a comprehensive theoretical investigation on the diffraction patterns of ETASR gratings is conducted. Theoretical results show that novel carpet beams with beautiful optical structures and distinctive characteristics have been constructed on the basics of the ETASR grating. Their diffraction patterns are independent of propagation distance, that is, the new carpet beams have diffraction-free propagating characteristics. The non-diffracting carpet beams are divided into two types by beam characteristics: non-diffracting integer-order and half-integer-order carpet beams. Subsequently, we experimentally generate these carpet beams using the ETASR grating. Finally, their particularly interesting optical morphology and features are explored through numerical simulations and experiments. In this work, we introduce a kind of new structured radial grating, which is named the even-type sinusoidal amplitude radial (ETASR) grating. Based on diffraction theory and the principle of stationary phase, a comprehensive theoretical investigation on the diffraction patterns of ETASR gratings is conducted. Theoretical results show that novel carpet beams with beautiful optical structures and distinctive characteristics have been constructed on the basics of the ETASR grating. Their diffraction patterns are independent of propagation distance, that is, the new carpet beams have diffraction-free propagating characteristics. The non-diffracting carpet beams are divided into two types by beam characteristics: non-diffracting integer-order and half-integer-order carpet beams. Subsequently, we experimentally generate these carpet beams using the ETASR grating. Finally, their particularly interesting optical morphology and features are explored through numerical simulations and experiments.
Chinese Optics Letters
- Publication Date: Jul. 16, 2024
- Vol. 22, Issue 7, 072601 (2024)
Constructing arbitrary self-similar Bessel-like beams via transverse-longitudinal mapping|On the Cover
Yanke Li, Yu Zou, Zhaojin Guo, Sheng Liu, Peng Li, Bingyan Wei, Dandan Wen, and Jianlin Zhao
Based on the transverse-longitudinal mapping of Bessel beams, we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation. Specifically, the propagating-variant width of this beam can be flexibly predesigned. We experimentally demonstrate three types of self-similar Bessel-like beams whose width variations are linear, piecewise, and period functions of propagation distance, respectively. The experimental results match well with the theoretical predictions. We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams. Based on the transverse-longitudinal mapping of Bessel beams, we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation. Specifically, the propagating-variant width of this beam can be flexibly predesigned. We experimentally demonstrate three types of self-similar Bessel-like beams whose width variations are linear, piecewise, and period functions of propagation distance, respectively. The experimental results match well with the theoretical predictions. We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.
Chinese Optics Letters
- Publication Date: Feb. 27, 2024
- Vol. 22, Issue 2, 022601 (2024)
Constructing ultra-long focal fields via tightly focused Bessel beams
Zhaojin Guo, Mingshuai Huang, Sheng Liu, Peng Li, Bingyan Wei, and Jianlin Zhao
We numerically demonstrate that the tight focusing of Bessel beams can generate focal fields with an ultra-long depth of focus (DOF). The ultra-long focal field can be controlled by appropriately regulating the order of the Bessel function and the polarization. An optical needle and an optical dark channel with nearly 100λ DOF are generated. The optical needle has a DOF of ∼104.9λ and a super-diffraction-limited focal spot with the size of 0.19λ2. The dark channel has a full-width at half-maximum of ∼0.346λ and a DOF of ∼103.8λ. Furthermore, the oscillating focal field with an ultra-long DOF can be also generated by merely changing the order of the input Bessel beam. Our results are expected to contribute to potential applications in optical tweezers, atom guidance and capture, and laser processing. We numerically demonstrate that the tight focusing of Bessel beams can generate focal fields with an ultra-long depth of focus (DOF). The ultra-long focal field can be controlled by appropriately regulating the order of the Bessel function and the polarization. An optical needle and an optical dark channel with nearly 100λ DOF are generated. The optical needle has a DOF of ∼104.9λ and a super-diffraction-limited focal spot with the size of 0.19λ2. The dark channel has a full-width at half-maximum of ∼0.346λ and a DOF of ∼103.8λ. Furthermore, the oscillating focal field with an ultra-long DOF can be also generated by merely changing the order of the input Bessel beam. Our results are expected to contribute to potential applications in optical tweezers, atom guidance and capture, and laser processing.
Chinese Optics Letters
- Publication Date: Jul. 10, 2023
- Vol. 21, Issue 7, 072601 (2023)
Quantum-limited resolution of partially coherent sources
Ben Wang, Liang Xu, Hongkuan Xia, Aonan Zhang, Kaimin Zheng, and Lijian Zhang
Discriminating two spatially separated sources is one of the most fundamental problems in imaging. Recent research based on quantum parameter estimation theory shows that the resolution limit of two incoherent point sources given by Rayleigh can be broken. However, in realistic optical systems, there often exists coherence in the imaging light field, and there have been efforts to analyze the optical resolution in the presence of partial coherence. Nevertheless, how the degree of coherence between two point sources affects the resolution has not been fully understood. Here, we analyze the quantum-limited resolution of two partially coherent point sources by explicitly relating the state after evolution through the optical systems to the coherence of the sources. In particular, we consider the situation in which coherence varies with the separation. We propose a feasible experiment scheme to realize the nearly optimal measurement, which adaptively chooses the binary spatial-mode demultiplexing measurement and direct imaging. Our results will have wide applications in imaging involving coherence of light. Discriminating two spatially separated sources is one of the most fundamental problems in imaging. Recent research based on quantum parameter estimation theory shows that the resolution limit of two incoherent point sources given by Rayleigh can be broken. However, in realistic optical systems, there often exists coherence in the imaging light field, and there have been efforts to analyze the optical resolution in the presence of partial coherence. Nevertheless, how the degree of coherence between two point sources affects the resolution has not been fully understood. Here, we analyze the quantum-limited resolution of two partially coherent point sources by explicitly relating the state after evolution through the optical systems to the coherence of the sources. In particular, we consider the situation in which coherence varies with the separation. We propose a feasible experiment scheme to realize the nearly optimal measurement, which adaptively chooses the binary spatial-mode demultiplexing measurement and direct imaging. Our results will have wide applications in imaging involving coherence of light.
Chinese Optics Letters
- Publication Date: Mar. 10, 2023
- Vol. 21, Issue 4, 042601 (2023)
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