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Optical Materials|58 Article(s)
CMOS-compatible UV–NIR high-responsivity photodetector based on flat femtosecond-laser sulfur-hyperdoped silicon
Guanting Song, Xu Zhou, Jiaxin Cao, Ziyang Zheng, Qiang Wu, and Jingjun Xu
Silicon-based photodetectors are experiencing significant demand for realizing infrared photodetection, night vision imaging, and ultraviolet-enhanced monitoring and communication. Recently, femtosecond-laser (fs-laser) hyperdoped silicon photodetectors have gained attention as promising alternatives to conventional silicon-based devices, owing to their exceptional properties, including high detectivity at low operating bias, broadband response spectrum beyond the bandgap limitation, wide operational temperature range, and ultrahigh dynamic range. Despite these advantages, the practical application of fs-laser hyperdoped devices has been hindered by challenges such as uneven surface structures and numerous lattice defects, which impede industrialization, chip integration, and ultraviolet photodetection performance. In this study, we present, to our knowledge, a novel design of flat fs-laser hyperdoped silicon materials and photodetectors tailored for complementary metal-oxide-semiconductor (CMOS) compatibility. A key innovation lies in the reduction of surface structure dimensions by three orders of magnitude, enabling the integration of fs-laser hyperdoped silicon as a photodetection layer in back-illuminated CMOS devices. The proposed photodetector achieves a peak responsivity of 120.07 A/W and a specific detectivity of 1.27 × 1014 Jones at 840 nm, marking the highest performance reported for fs-laser hyperdoped silicon photodetectors. Furthermore, it demonstrates ultraviolet enhancement and sub-bandgap infrared photodetection simultaneously, with responsivities exceeding 10 A/W across a broad spectrum from 350 to 1170 nm at 5 V. This breakthrough not only paves the way for fs-laser hyperdoped silicon in array photodetection but also facilitates its integration with silicon-based chip fabrication processes, addressing critical bottlenecks for industrialization and advancing the field of silicon photonics. Silicon-based photodetectors are experiencing significant demand for realizing infrared photodetection, night vision imaging, and ultraviolet-enhanced monitoring and communication. Recently, femtosecond-laser (fs-laser) hyperdoped silicon photodetectors have gained attention as promising alternatives to conventional silicon-based devices, owing to their exceptional properties, including high detectivity at low operating bias, broadband response spectrum beyond the bandgap limitation, wide operational temperature range, and ultrahigh dynamic range. Despite these advantages, the practical application of fs-laser hyperdoped devices has been hindered by challenges such as uneven surface structures and numerous lattice defects, which impede industrialization, chip integration, and ultraviolet photodetection performance. In this study, we present, to our knowledge, a novel design of flat fs-laser hyperdoped silicon materials and photodetectors tailored for complementary metal-oxide-semiconductor (CMOS) compatibility. A key innovation lies in the reduction of surface structure dimensions by three orders of magnitude, enabling the integration of fs-laser hyperdoped silicon as a photodetection layer in back-illuminated CMOS devices. The proposed photodetector achieves a peak responsivity of 120.07 A/W and a specific detectivity of 1.27 × 1014 Jones at 840 nm, marking the highest performance reported for fs-laser hyperdoped silicon photodetectors. Furthermore, it demonstrates ultraviolet enhancement and sub-bandgap infrared photodetection simultaneously, with responsivities exceeding 10 A/W across a broad spectrum from 350 to 1170 nm at 5 V. This breakthrough not only paves the way for fs-laser hyperdoped silicon in array photodetection but also facilitates its integration with silicon-based chip fabrication processes, addressing critical bottlenecks for industrialization and advancing the field of silicon photonics.
Chinese Optics Letters
- Publication Date: Aug. 13, 2025
- Vol. 23, Issue 9, 091602 (2025)
Low energy consumption and fast electro-optic switching in polymer-confined ferroelectric nematics
Susanta Chakraborty, Jiayao Ye, Luyao Sun, Jidan Yang, Satoshi Aya, Yanqing Lu, and Bingxiang Li
Polymer-embedded liquid crystals (LCs) play a pivotal role in smart applications, enabling precise tunability over electro-optical properties. However, high energy consumption in conventional LC-polymeric systems limits their efficiency in sustainable and environmental protection technologies. Reducing driving voltage without compromising mechanical and electro-optical performance remains an unresolved challenge. Here, we demonstrate a polymer-confined ferroelectric nematic (NF) liquid crystal system, polymerized with mesogenic and non-mesogenic monomers under an electric field. The effective multidomain polymer structure exploits the intriguing properties of the NF LC and generates a highly scattered state with an excellent contrast ratio in the NF phase. Electric field-controlled reorientation of directors leads to a transparent state at a very small voltage. The system demonstrates the advantages of a low driving voltage, sub-millisecond switching time with negligible hysteresis, and improved durability, promoting applications in energy-saving smart windows. This work reveals valuable insights into leveraging NF LCs and tailoring polymer networks to advance the performance of electro-optic devices. Polymer-embedded liquid crystals (LCs) play a pivotal role in smart applications, enabling precise tunability over electro-optical properties. However, high energy consumption in conventional LC-polymeric systems limits their efficiency in sustainable and environmental protection technologies. Reducing driving voltage without compromising mechanical and electro-optical performance remains an unresolved challenge. Here, we demonstrate a polymer-confined ferroelectric nematic (NF) liquid crystal system, polymerized with mesogenic and non-mesogenic monomers under an electric field. The effective multidomain polymer structure exploits the intriguing properties of the NF LC and generates a highly scattered state with an excellent contrast ratio in the NF phase. Electric field-controlled reorientation of directors leads to a transparent state at a very small voltage. The system demonstrates the advantages of a low driving voltage, sub-millisecond switching time with negligible hysteresis, and improved durability, promoting applications in energy-saving smart windows. This work reveals valuable insights into leveraging NF LCs and tailoring polymer networks to advance the performance of electro-optic devices.
Chinese Optics Letters
- Publication Date: Sep. 08, 2025
- Vol. 23, Issue 9, 091601 (2025)
Blue LED-excitable ultra broadband near-infrared luminescence based on KCdF3:Cr3+ /Ni2+ nanocrystals embedded in fluorosilicate glass
Long Chen, Junhuan Lai, Yong Xu, Yinsheng Xu, and Xueyun Liu
The growing demand for broadband near-infrared (NIR) irradiation in security, biomedicine, and food science is driving the development of new NIR light sources. Herein, a series of Cr3+/Ni2+ co-doped transparent glass ceramics containing octahedrally coordinated KCdF3 nanocrystals have been successfully prepared. Under 450 nm blue light excitation, the combination of Cr3+ and Ni2+ results in an ultra-broadband NIR emission band ranging from 700 to 1800 nm. Based on the excitation and emission spectra and the decay lifetime curves, the energy transfer (ET) efficiency from Cr3+ to Ni2+ is confirmed to be 50.2%. A glass ceramic-converted NIR-LED was fabricated by integrating a commercial blue LED chip with a representative Cr3+/Ni2+ co-doped glass ceramic and has demonstrated potential applications in the areas of covert information recognition and night vision illumination. Our investigation provides new insights into the development of ultra-broadband NIR light sources that are both cost-effective and efficient. The growing demand for broadband near-infrared (NIR) irradiation in security, biomedicine, and food science is driving the development of new NIR light sources. Herein, a series of Cr3+/Ni2+ co-doped transparent glass ceramics containing octahedrally coordinated KCdF3 nanocrystals have been successfully prepared. Under 450 nm blue light excitation, the combination of Cr3+ and Ni2+ results in an ultra-broadband NIR emission band ranging from 700 to 1800 nm. Based on the excitation and emission spectra and the decay lifetime curves, the energy transfer (ET) efficiency from Cr3+ to Ni2+ is confirmed to be 50.2%. A glass ceramic-converted NIR-LED was fabricated by integrating a commercial blue LED chip with a representative Cr3+/Ni2+ co-doped glass ceramic and has demonstrated potential applications in the areas of covert information recognition and night vision illumination. Our investigation provides new insights into the development of ultra-broadband NIR light sources that are both cost-effective and efficient.
Chinese Optics Letters
- Publication Date: Jul. 03, 2025
- Vol. 23, Issue 8, 081601 (2025)
2D bismuth/Ga2O3 van der Waals heterostructure for ultraviolet photodetectors with high responsivity and detectivity
Zhengjie Xu, Dianmeng Dong, Min Peng, Tianyi Cheng, Fan Zhang, Zhibin Yang, and Zhenping Wu
Gallium oxide (Ga2O3), a promising candidate in ultraviolet photodetection, suffers significant limitations in its optoelectronic performance owing to the challenge of achieving p-type doping. To address this challenge, we designed a type-I heterostructure photodetector (PD) by depositing two-dimensional Bi films on Ga2O3 using the pulsed laser deposition technique. Under the illumination intensity of 0.1 µW/cm2, this PD exhibits a remarkable responsivity of up to 200 mA/W and a detectivity of 8.58 × 1011 Jones, demonstrating its excellent low-light detection ability. In addition, due to the built-in electric field of the heterojunction, the device can effectively suppress the dark current and has the performance of self-powered detection. Gallium oxide (Ga2O3), a promising candidate in ultraviolet photodetection, suffers significant limitations in its optoelectronic performance owing to the challenge of achieving p-type doping. To address this challenge, we designed a type-I heterostructure photodetector (PD) by depositing two-dimensional Bi films on Ga2O3 using the pulsed laser deposition technique. Under the illumination intensity of 0.1 µW/cm2, this PD exhibits a remarkable responsivity of up to 200 mA/W and a detectivity of 8.58 × 1011 Jones, demonstrating its excellent low-light detection ability. In addition, due to the built-in electric field of the heterojunction, the device can effectively suppress the dark current and has the performance of self-powered detection.
Chinese Optics Letters
- Publication Date: Jun. 17, 2025
- Vol. 23, Issue 7, 071601 (2025)
39 Influence of defect anisotropy on luminescence properties in Pr:YAP crystals
Lu Zhang, Bowen Jiang, Mingyan Pan, Weiguo Ji, Qiming Fan, Shaoqing Cui, Ning Jia, Qinglin Sai, and Hongji Qi
This study aims to investigate the anisotropic properties of Pr:YAP on (100), (010), and (001) crystal planes. Raman spectroscopy shows anisotropy in vibrational modes, but absorption spectra display no significant anisotropy. X-ray excited luminescence (XEL) and photoluminescence (PL) spectra reveal anisotropy in Pr3+ and F+ luminescence intensities. The PL decay time (∼7 ns) indicates similar luminescence mechanisms. The anisotropic defect distribution observed in thermoluminescence analysis can be explained using areal ion density and the offset parameter of Al atoms. Ultimately, it is inferred that shallow-level defects compete with Pr3+ ions, leading to variations in anisotropic luminescence intensity. This study aims to investigate the anisotropic properties of Pr:YAP on (100), (010), and (001) crystal planes. Raman spectroscopy shows anisotropy in vibrational modes, but absorption spectra display no significant anisotropy. X-ray excited luminescence (XEL) and photoluminescence (PL) spectra reveal anisotropy in Pr3+ and F+ luminescence intensities. The PL decay time (∼7 ns) indicates similar luminescence mechanisms. The anisotropic defect distribution observed in thermoluminescence analysis can be explained using areal ion density and the offset parameter of Al atoms. Ultimately, it is inferred that shallow-level defects compete with Pr3+ ions, leading to variations in anisotropic luminescence intensity.
Chinese Optics Letters
- Publication Date: May. 30, 2025
- Vol. 23, Issue 6, 061601 (2025)
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)
Ultra-high concentration Ce3+-doped gadolinium-based borosilicate glass scintillators
Xinyuan Sun, Zhehao Hua, Sen Qian, Hua Cai, Jifeng Han, Lili Hu, Weichang Li, Xusheng Qiao, Jing Ren, Gao Tang, Shenghua Yin, Huiping Yuan, and Minghui Zhang
Ce3+-doped gadolinium-based borosilicate (GBSCx) glass scintillators with an ultra-high concentration of 16% (mole fraction) were synthesized in ambient atmosphere for future calorimeter application. The valence state of Ce was precisely controlled in the glass by the X-ray absorption near edge structure (XANES) spectrum. With the increased Ce3+ concentration, the bridging oxygen (BO)/non-bridging oxygen (NBO) ratio decreases notably from 5.15 to 0.56. The GBSCx glass scintillators exhibit the broad photoluminescence (PL) band within 350–550 nm regions, with a maximum PL quantum yield (PL QY) of 60.6%. In X-ray excited luminescence (XEL), the integral intensity of the GBSC2 glass is 18.4% compared to the BGO crystal. Meanwhile, it has the highest light yield of 1043 photons/MeV with an energy resolution of 28.4% at 662 keV under γ-ray excitation. When the doped concentration of Ce3+ exceeds 4% (mole fraction), the proportion of light yield within 1 µs integral gate exceeds 95%, which conforms to the requirement of fast time response. Interestingly, the concentration quenching effect of high concentration Ce3+ (x ≤ 14) does not occur in the glass scintillators under γ-ray excitation. With the increase of Ce3+ concentration, both the fast (100–18 ns) and slow (1000–59 ns) components of scintillation decay time decrease dramatically. Therefore, the developed GBSCx glass scintillators, featured with the reasonable light yield and fast time response, have a promising application in future high energy physics (HEP) experiments. Ce3+-doped gadolinium-based borosilicate (GBSCx) glass scintillators with an ultra-high concentration of 16% (mole fraction) were synthesized in ambient atmosphere for future calorimeter application. The valence state of Ce was precisely controlled in the glass by the X-ray absorption near edge structure (XANES) spectrum. With the increased Ce3+ concentration, the bridging oxygen (BO)/non-bridging oxygen (NBO) ratio decreases notably from 5.15 to 0.56. The GBSCx glass scintillators exhibit the broad photoluminescence (PL) band within 350–550 nm regions, with a maximum PL quantum yield (PL QY) of 60.6%. In X-ray excited luminescence (XEL), the integral intensity of the GBSC2 glass is 18.4% compared to the BGO crystal. Meanwhile, it has the highest light yield of 1043 photons/MeV with an energy resolution of 28.4% at 662 keV under γ-ray excitation. When the doped concentration of Ce3+ exceeds 4% (mole fraction), the proportion of light yield within 1 µs integral gate exceeds 95%, which conforms to the requirement of fast time response. Interestingly, the concentration quenching effect of high concentration Ce3+ (x ≤ 14) does not occur in the glass scintillators under γ-ray excitation. With the increase of Ce3+ concentration, both the fast (100–18 ns) and slow (1000–59 ns) components of scintillation decay time decrease dramatically. Therefore, the developed GBSCx glass scintillators, featured with the reasonable light yield and fast time response, have a promising application in future high energy physics (HEP) experiments.
Chinese Optics Letters
- Publication Date: Oct. 15, 2025
- Vol. 23, Issue 12, 121602 (2025)
PtTe2 thin film photodetectors with positive photoconductivity under UV-Vis-NIR laser irradiation
Liping Liu, Langlang Du, Eryi Pan, Xun Liu, Jingwen Chen, Le Yu, Yu Yu, Haiting Zhang, Xiaoxian Song, Xing Yang, and Jianquan Yao
PtTe2, as a two-dimensional (2D) material with unique physicochemical properties, has become a key research object that researchers focus on. In this paper, the PtTe2 thin film photodetectors are fabricated through the chemical vapor deposition technique. The surface morphology of the PtTe2 thin films is uniform, and the films can be densely packed, effectively reducing the electronic defects and carrier scattering, which can improve the photoelectric conversion process, the response speed, and the sensitivity. The PtTe2 device demonstrates a broadband spectral response spanning from ultraviolet (UV) to near-infrared (NIR) wavelengths. Under irradiation with lasers at 375, 532, and 808 nm, the 6.9 nm thin film PtTe2 device exhibits a positive photoconductivity phenomenon. The photoresponsivity, specific detectivity, and the device’s response time for a single cycle under the 375 nm laser irradiation were found to be 2.39 A/W, 4.01 × 1010 Jones, and 0.21/0.20 s, respectively. Furthermore, a single-site scanning imaging system using a PtTe2 photodetector has been developed. High-resolution images of three characters, “U,” “J,” and “S,” have been successfully achieved under 532 nm laser radiation. This work provides valuable experience for the application of the 2D material PtTe2 in the fields of optical detection, optical sensing, and optical communication. PtTe2, as a two-dimensional (2D) material with unique physicochemical properties, has become a key research object that researchers focus on. In this paper, the PtTe2 thin film photodetectors are fabricated through the chemical vapor deposition technique. The surface morphology of the PtTe2 thin films is uniform, and the films can be densely packed, effectively reducing the electronic defects and carrier scattering, which can improve the photoelectric conversion process, the response speed, and the sensitivity. The PtTe2 device demonstrates a broadband spectral response spanning from ultraviolet (UV) to near-infrared (NIR) wavelengths. Under irradiation with lasers at 375, 532, and 808 nm, the 6.9 nm thin film PtTe2 device exhibits a positive photoconductivity phenomenon. The photoresponsivity, specific detectivity, and the device’s response time for a single cycle under the 375 nm laser irradiation were found to be 2.39 A/W, 4.01 × 1010 Jones, and 0.21/0.20 s, respectively. Furthermore, a single-site scanning imaging system using a PtTe2 photodetector has been developed. High-resolution images of three characters, “U,” “J,” and “S,” have been successfully achieved under 532 nm laser radiation. This work provides valuable experience for the application of the 2D material PtTe2 in the fields of optical detection, optical sensing, and optical communication.
Chinese Optics Letters
- Publication Date: Oct. 21, 2025
- Vol. 23, Issue 12, 121601 (2025)
Mn2+-doped glass scintillators with anti-thermal quenching for high-temperature X-ray imaging
Lianjie Li, Qiqi Su, Junyu Chen, Guanlin He, Huihui Lin, Hongjun Li, and Hai Guo
Glass scintillators with high X-ray excited luminescence (XEL) intensity, superior thermal stability, and excellent spatial resolution are expected to be applied in high-temperature X-ray imaging applications. In this study, Mn2+-doped fluoroaluminosilicate glass scintillators with excellent scintillating performance and anti-thermal quenching behavior were successfully prepared. The optimal sample has excellent XEL intensity [83.9% of that of commercial Bi4Ge3O12 (BGO) scintillators] and good irradiation resistance and reusability. Notably, due to the thermal compensation effect, the optimal sample exhibits anti-thermal quenching behavior (XEL intensity at 393 K is 104% of that at 303 K) and excellent thermal stability (XEL intensity at 573 K maintains 61% of that at 303 K), which has superior thermal stability to that of BGO (XEL intensity at 393 K is 19% of that at 303 K). In addition, the optimal sample is applied to X-ray imaging, and its spatial resolution reaches 20 lp/mm. High-temperature X-ray imaging reveals that imaging clarity enhances with increasing temperature. In summary, Mn2+-doped fluoroaluminosilicate glass scintillators exhibit superior high-temperature stability and imaging performance, and provide, to our knowledge, a new type of scintillating material with potential applications in the field of radiation detection. Glass scintillators with high X-ray excited luminescence (XEL) intensity, superior thermal stability, and excellent spatial resolution are expected to be applied in high-temperature X-ray imaging applications. In this study, Mn2+-doped fluoroaluminosilicate glass scintillators with excellent scintillating performance and anti-thermal quenching behavior were successfully prepared. The optimal sample has excellent XEL intensity [83.9% of that of commercial Bi4Ge3O12 (BGO) scintillators] and good irradiation resistance and reusability. Notably, due to the thermal compensation effect, the optimal sample exhibits anti-thermal quenching behavior (XEL intensity at 393 K is 104% of that at 303 K) and excellent thermal stability (XEL intensity at 573 K maintains 61% of that at 303 K), which has superior thermal stability to that of BGO (XEL intensity at 393 K is 19% of that at 303 K). In addition, the optimal sample is applied to X-ray imaging, and its spatial resolution reaches 20 lp/mm. High-temperature X-ray imaging reveals that imaging clarity enhances with increasing temperature. In summary, Mn2+-doped fluoroaluminosilicate glass scintillators exhibit superior high-temperature stability and imaging performance, and provide, to our knowledge, a new type of scintillating material with potential applications in the field of radiation detection.
Chinese Optics Letters
- Publication Date: Oct. 16, 2025
- Vol. 23, Issue 11, 111602 (2025)
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