Magnetic skyrmions are topologically protected quasiparticles and have drawn much attention because of their potential applications in next-generation spintronics devices. Their inherent topological stability, nanoscale size, and efficient manipulation via spin currents make them promising candidates for high-density data storage and advanced computing paradigms. We micromagnetically investigate the nucleation dynamics of magnetic skyrmion pairs excited underneath two 30 nm nanocontacts with varying separations on top of an extended Co/Pt bilayer thin film. At close separation of 100 nm, the magnetization configurations strongly interact, giving rise to the formation of stable merged skyrmion states. As the separation increases beyond 200 nm, topologically distinct metastable configurations emerge, including the coexistence of tunable skyrmion–antiskyrmion pairs through Dzyaloshinskii–Moriya interaction strengths and current pulse amplitudes. These metastable states eventually relax into two stable skyrmions that can be independently toggled ON and OFF using a weak in-plane magnetic field, enabling complex logic operations and more flexible circuit designs. Beyond the fundamental interest in skyrmion interaction dynamics, the independent control of skyrmion–antiskyrmion states holds promise for next-generation spintronic devices, with potential applications in memory, logic, and computing.
{"title":"Tunable skyrmion–antiskyrmion dynamics in Co/Pt nanocontacts for spintronic applications","authors":"Hind Prakash, Himanshu Fulara","doi":"10.1063/5.0243699","DOIUrl":"https://doi.org/10.1063/5.0243699","url":null,"abstract":"Magnetic skyrmions are topologically protected quasiparticles and have drawn much attention because of their potential applications in next-generation spintronics devices. Their inherent topological stability, nanoscale size, and efficient manipulation via spin currents make them promising candidates for high-density data storage and advanced computing paradigms. We micromagnetically investigate the nucleation dynamics of magnetic skyrmion pairs excited underneath two 30 nm nanocontacts with varying separations on top of an extended Co/Pt bilayer thin film. At close separation of 100 nm, the magnetization configurations strongly interact, giving rise to the formation of stable merged skyrmion states. As the separation increases beyond 200 nm, topologically distinct metastable configurations emerge, including the coexistence of tunable skyrmion–antiskyrmion pairs through Dzyaloshinskii–Moriya interaction strengths and current pulse amplitudes. These metastable states eventually relax into two stable skyrmions that can be independently toggled ON and OFF using a weak in-plane magnetic field, enabling complex logic operations and more flexible circuit designs. Beyond the fundamental interest in skyrmion interaction dynamics, the independent control of skyrmion–antiskyrmion states holds promise for next-generation spintronic devices, with potential applications in memory, logic, and computing.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"181 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a multifunctional device was developed using the organic piezoelectric material polyvinylidene fluoride (PVDF) to detect mechanical operations. This device utilizes a mechanism in which the resonance of the element structure is excited and detected using PVDF. This enabled the proposal of a device principle that can allow detection of various physical quantities, such as differential pressure and acceleration. The device can detect low pressures of up to 1.5 kPa with a sensitivity of −0.19 Hz/Pa. Additionally, it can measure acceleration with output linearity and cross-axis sensitivity. This device is advantageous because it can evaluate both pressure and acceleration using a common sensor structure and measurement methods, and it can be manufactured at room temperature using inexpensive materials. It holds potential for applications in the maintenance of various industrial machinery and monitoring of natural disasters.
{"title":"Resonant-type multifunctional device using organic piezoelectrics for detecting differential pressure and acceleration","authors":"Yuki Noda, Kunihiro Matsubara, Naomi Toyoshima, Tsuyoshi Sekitani","doi":"10.1063/5.0246846","DOIUrl":"https://doi.org/10.1063/5.0246846","url":null,"abstract":"In this study, a multifunctional device was developed using the organic piezoelectric material polyvinylidene fluoride (PVDF) to detect mechanical operations. This device utilizes a mechanism in which the resonance of the element structure is excited and detected using PVDF. This enabled the proposal of a device principle that can allow detection of various physical quantities, such as differential pressure and acceleration. The device can detect low pressures of up to 1.5 kPa with a sensitivity of −0.19 Hz/Pa. Additionally, it can measure acceleration with output linearity and cross-axis sensitivity. This device is advantageous because it can evaluate both pressure and acceleration using a common sensor structure and measurement methods, and it can be manufactured at room temperature using inexpensive materials. It holds potential for applications in the maintenance of various industrial machinery and monitoring of natural disasters.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A radio-over-fiber (RoF) link simplifies the base station and network structure, adapting to the trends of high capacity and rapid development in modern communication. The development of 2-μm-band links improves the capacity of communication systems, which can solve future optical fiber capacity crises. In this work, a relaxed high-Sn-content GeSn absorption layer was grown on a Si substrate, and high-power GeSn photodetectors were fabricated. The photodetectors achieved a low dark current with a cutoff wavelength of about 2930 nm. The GeSn photodetectors had a saturated photocurrent of up to 70 mA operating in the 2-μm-wavelength range and a 3-dB bandwidth of approximately 1.6 GHz. The results provide a technical reference for the application of GeSn 2-μm detectors in RoF links.
{"title":"High-power GeSn photodetector for 2-μm RoF system","authors":"Jinlai Cui, Jun Zheng, Xiangquan Liu, Yiyang Wu, Jiayi Li, Qinxing Huang, Yuhua Zuo, Zhi Liu, Buwen Cheng","doi":"10.1063/5.0250619","DOIUrl":"https://doi.org/10.1063/5.0250619","url":null,"abstract":"A radio-over-fiber (RoF) link simplifies the base station and network structure, adapting to the trends of high capacity and rapid development in modern communication. The development of 2-μm-band links improves the capacity of communication systems, which can solve future optical fiber capacity crises. In this work, a relaxed high-Sn-content GeSn absorption layer was grown on a Si substrate, and high-power GeSn photodetectors were fabricated. The photodetectors achieved a low dark current with a cutoff wavelength of about 2930 nm. The GeSn photodetectors had a saturated photocurrent of up to 70 mA operating in the 2-μm-wavelength range and a 3-dB bandwidth of approximately 1.6 GHz. The results provide a technical reference for the application of GeSn 2-μm detectors in RoF links.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"20 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electron beam (e-beam) generated plasmas with applied crossed electric and magnetic (E×B) fields are promising for low-damage (gentle) material processing. However, these plasmas can be subject to the formation of plasma non-uniformities propagating in the E×B direction. These rotating plasma structures (or “spokes”) enhance the transport of charged species across the magnetic field, which can harm the gentle processing capability of the plasma. In this work, we investigate the role of electrostatically active boundaries on the spoke formation by incorporating a variable bias conducting boundary (known as an anticathode) placed on the axially opposite side of the cathode. Our findings indicate azimuthal mode suppression occurs when the anticathode is electron collecting. Furthermore, we show selective azimuthal mode suppression by biasing the anticathode to an intermediate potential between the cathode and anode potentials. These findings suggest a link between the axial electron confinement in the e-beam generated plasma and azimuthally propagating plasma structure formation.
{"title":"Anticathode effect on multimodal azimuthal oscillations in electron beam generated E×B plasma","authors":"Nirbhav Singh Chopra, Yevgeny Raitses","doi":"10.1063/5.0252744","DOIUrl":"https://doi.org/10.1063/5.0252744","url":null,"abstract":"Electron beam (e-beam) generated plasmas with applied crossed electric and magnetic (E×B) fields are promising for low-damage (gentle) material processing. However, these plasmas can be subject to the formation of plasma non-uniformities propagating in the E×B direction. These rotating plasma structures (or “spokes”) enhance the transport of charged species across the magnetic field, which can harm the gentle processing capability of the plasma. In this work, we investigate the role of electrostatically active boundaries on the spoke formation by incorporating a variable bias conducting boundary (known as an anticathode) placed on the axially opposite side of the cathode. Our findings indicate azimuthal mode suppression occurs when the anticathode is electron collecting. Furthermore, we show selective azimuthal mode suppression by biasing the anticathode to an intermediate potential between the cathode and anode potentials. These findings suggest a link between the axial electron confinement in the e-beam generated plasma and azimuthally propagating plasma structure formation.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"30 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this Letter, we demonstrate the application of Deep Level Transient Spectroscopy (DLTS) and Laplace DLTS (L-DLTS) techniques to unintentionally doped β-Ga2O3 crystals grown by the Czochralski method. It is clearly shown that the capacitance signal associated with the electron emission from a trap level previously identified in the literature as E14 and characterized by an activation energy of 0.18 eV is found to be a superposition of electron emissions from two closely spaced energy levels. Furthermore, we noted that the corresponding L-DLTS signal splits into two well separated components with activation energies of 196 and 209 meV, and the splitting occurs as the electric field in the space charge region of a Schottky diode exceeds 2 × 107 V/m (0.2 MV/cm). Additionally, a strong dependency of DLTS and L-DLTS signals on the electric field strength and resulting enhancement of the electron emission from these two trap states agree well with the 1D Poole–Frenkel (PF) model, suggesting donor-like behavior of both states. Finally, we found that the barrier height for thermal emission of the electrons is significantly reduced in our samples by 121 meV due to the PF effect for experimental conditions corresponding to an electric field of 3.5 × 107 V/m (0.35 MV/cm).
{"title":"The electric field influence on EC-0.18 eV electron trap level in (100)-oriented β-Ga2O3 crystals grown by the Czochralski method","authors":"P. Kruszewski, A. Fiedler, Z. Galazka","doi":"10.1063/5.0251567","DOIUrl":"https://doi.org/10.1063/5.0251567","url":null,"abstract":"In this Letter, we demonstrate the application of Deep Level Transient Spectroscopy (DLTS) and Laplace DLTS (L-DLTS) techniques to unintentionally doped β-Ga2O3 crystals grown by the Czochralski method. It is clearly shown that the capacitance signal associated with the electron emission from a trap level previously identified in the literature as E14 and characterized by an activation energy of 0.18 eV is found to be a superposition of electron emissions from two closely spaced energy levels. Furthermore, we noted that the corresponding L-DLTS signal splits into two well separated components with activation energies of 196 and 209 meV, and the splitting occurs as the electric field in the space charge region of a Schottky diode exceeds 2 × 107 V/m (0.2 MV/cm). Additionally, a strong dependency of DLTS and L-DLTS signals on the electric field strength and resulting enhancement of the electron emission from these two trap states agree well with the 1D Poole–Frenkel (PF) model, suggesting donor-like behavior of both states. Finally, we found that the barrier height for thermal emission of the electrons is significantly reduced in our samples by 121 meV due to the PF effect for experimental conditions corresponding to an electric field of 3.5 × 107 V/m (0.35 MV/cm).","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"15 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei Tan, Yu-Fei Lang, Yu-Xuan Li, Yu-Qing Zhao, Yee-Sin Ang
The contact between two-dimensional (2D) perovskite and metal electrodes is often plagued by strong Fermi-level pinning (FLP) effects, which limit the electronic performance of devices. By utilizing van der Waals design strategies, the contact performance between Cs3Bi2I9 and 1T/H-XA2 (X = V, Nb, Ta; A = S, Se) was investigated. P-type Schottky contacts are obtained in all 1T/H-XA2 contacts to Cs3Bi2I9, and the contacts can be engineered from Schottky to Ohmic contacts via external electric fields. Furthermore, a large pinning factor to suppress the FLP effects was observed to approach the Schottky–Mott limit, and the origin is elucidated. In addition, the transport properties of various 2D metals contacts to Cs3Bi2I9 were calculated and screened out. Finally, Curie temperature (Tc) of magnetic systems were calculated using the Monte Carlo method, and the Tc of 1H-VS2/Cs3Bi2I9 significantly enhances largely to surpass room temperature, thereby expanding the application field of spintronic devices. This study provides potential guidance for the design of efficient 2D Cs3Bi2I9-based nanodevices as well as high-temperature spintronic devices.
{"title":"Designing the weak Fermi pinning and p-type Ohmic contacts to monolayer halide perovskite Cs3Bi2I9","authors":"Wei Tan, Yu-Fei Lang, Yu-Xuan Li, Yu-Qing Zhao, Yee-Sin Ang","doi":"10.1063/5.0243838","DOIUrl":"https://doi.org/10.1063/5.0243838","url":null,"abstract":"The contact between two-dimensional (2D) perovskite and metal electrodes is often plagued by strong Fermi-level pinning (FLP) effects, which limit the electronic performance of devices. By utilizing van der Waals design strategies, the contact performance between Cs3Bi2I9 and 1T/H-XA2 (X = V, Nb, Ta; A = S, Se) was investigated. P-type Schottky contacts are obtained in all 1T/H-XA2 contacts to Cs3Bi2I9, and the contacts can be engineered from Schottky to Ohmic contacts via external electric fields. Furthermore, a large pinning factor to suppress the FLP effects was observed to approach the Schottky–Mott limit, and the origin is elucidated. In addition, the transport properties of various 2D metals contacts to Cs3Bi2I9 were calculated and screened out. Finally, Curie temperature (Tc) of magnetic systems were calculated using the Monte Carlo method, and the Tc of 1H-VS2/Cs3Bi2I9 significantly enhances largely to surpass room temperature, thereby expanding the application field of spintronic devices. This study provides potential guidance for the design of efficient 2D Cs3Bi2I9-based nanodevices as well as high-temperature spintronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"20 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinghan Dong, Arthur C. Cardoso, Haichen Zhou, Jingrui Zhang, Weijie Nie, Alex S. Clark, John G. Rarity
Here, we present a high-sensitivity, rapid, and low-cost method for methane sensing based on a nonlinear interferometer. This method utilizes signal photons generated by stimulated parametric downconversion (ST-PDC), enabling the use of a silicon detector to capture high-precision methane absorption spectra in the mid-infrared region. By controlling the system loss, we achieve more significant changes in visibility, thereby increasing sensitivity. A low-cost CMOS camera is employed to capture spatial interference fringes, ensuring fast and efficient detection. Thereby, we demonstrate an accurate measurement of methane concentration within a gas cell. In addition, we show that ST-PDC enables long-distance sensing and the capability to measure open-path low ambient methane concentrations in the real world.
{"title":"Methane sensing via unbalanced nonlinear interferometry using a CMOS camera and undetected mid-infrared light","authors":"Jinghan Dong, Arthur C. Cardoso, Haichen Zhou, Jingrui Zhang, Weijie Nie, Alex S. Clark, John G. Rarity","doi":"10.1063/5.0242197","DOIUrl":"https://doi.org/10.1063/5.0242197","url":null,"abstract":"Here, we present a high-sensitivity, rapid, and low-cost method for methane sensing based on a nonlinear interferometer. This method utilizes signal photons generated by stimulated parametric downconversion (ST-PDC), enabling the use of a silicon detector to capture high-precision methane absorption spectra in the mid-infrared region. By controlling the system loss, we achieve more significant changes in visibility, thereby increasing sensitivity. A low-cost CMOS camera is employed to capture spatial interference fringes, ensuring fast and efficient detection. Thereby, we demonstrate an accurate measurement of methane concentration within a gas cell. In addition, we show that ST-PDC enables long-distance sensing and the capability to measure open-path low ambient methane concentrations in the real world.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"87 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yubin Hu, Degao Xu, Xiaoyan Li, Nan Jiang, Fangjun Wang, Jun Hong, Gang Ouyang, Wei Hu
Gallium oxide (Ga2O3), a wide bandgap semiconductor, has been extensively studied for its potential applications in deep ultraviolet photodetectors and next-generation power electronic devices. To enhance the optoelectronic properties of Ga2O3 films, a controllable doping strategy is proposed in this work. Using a sol-gel method, Ga2O3 films doped with magnesium (Mg) are prepared, with the Mg concentration adjustable through the precursor solution. The results indicate that the bandgap of Ga2O3 increases with higher doping levels, while the electrical conductivity decreases proportionally. To evaluate their optoelectronic characteristics, a series of photodetectors with Mg-doped Ga2O3 active layers are fabricated. Under a 254 nm incident light, the device with an optimal doping concentration of 4.2% demonstrates the best performance, achieving the highest responsivity (R) of 1.97 A/W and a photo-dark current ratio of 2.6 × 103. Furthermore, density functional theory calculations are employed to provide a detailed analysis of the fundamental mechanisms behind the enhanced optoelectronic properties. This approach to controllable and optimized doping in Ga2O3 films shows promise for future applications in semiconductor devices.
{"title":"A controllable doping method for Ga2O3 film construction and optimized density for high-performance photodetectors","authors":"Yubin Hu, Degao Xu, Xiaoyan Li, Nan Jiang, Fangjun Wang, Jun Hong, Gang Ouyang, Wei Hu","doi":"10.1063/5.0246775","DOIUrl":"https://doi.org/10.1063/5.0246775","url":null,"abstract":"Gallium oxide (Ga2O3), a wide bandgap semiconductor, has been extensively studied for its potential applications in deep ultraviolet photodetectors and next-generation power electronic devices. To enhance the optoelectronic properties of Ga2O3 films, a controllable doping strategy is proposed in this work. Using a sol-gel method, Ga2O3 films doped with magnesium (Mg) are prepared, with the Mg concentration adjustable through the precursor solution. The results indicate that the bandgap of Ga2O3 increases with higher doping levels, while the electrical conductivity decreases proportionally. To evaluate their optoelectronic characteristics, a series of photodetectors with Mg-doped Ga2O3 active layers are fabricated. Under a 254 nm incident light, the device with an optimal doping concentration of 4.2% demonstrates the best performance, achieving the highest responsivity (R) of 1.97 A/W and a photo-dark current ratio of 2.6 × 103. Furthermore, density functional theory calculations are employed to provide a detailed analysis of the fundamental mechanisms behind the enhanced optoelectronic properties. This approach to controllable and optimized doping in Ga2O3 films shows promise for future applications in semiconductor devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"27 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The power-boosted laser transmitted via a fiber tip sinusoidally excites the target trace molecules, generating a photothermal (PT) effect. The Gaussian-distributed plane wave heats the medium adjacent to the Fresnel reflection surface. Meanwhile, a continuous probe light traverses the heating field, and the periodic temperature change then modulates the phase of the probe light. A multi-beam interferometer formed by aligning the Fresnel reflection surface to a gold-coated high-reflection surface possesses high resolution and sensitivity, significantly enhancing the detection performance. A well-established theoretical model of instantaneous PT transduction and optical phase modulation is employed to obtain the optimized interferometric configuration. To validate the effective interferometric phase transformation within the cavity, a comparison is made between the simple silicon cavity and the gold-coated cavity. The limitation of detection of such extrinsic fiber-tip PT sensors indicates one magnitude lower as compared to the conventional PT interferometric gas sensor with such robust and compact sensing designs. This work lays a solid foundation for future research on gas laser phase modulators and nonlinear laser–matter interactions.
{"title":"Fiber-tip photothermal transducer with gold-coated multi-beam interferometric cavity for high sensitivity gas detection","authors":"Sixiang Ran, Wenjun Ni, Chunyong Yang, Zhongke Zhao, Zhengshuo Jiang, Qiaosong Lin, Bingze He, Ruiming Wu, Perry Ping Shum","doi":"10.1063/5.0240821","DOIUrl":"https://doi.org/10.1063/5.0240821","url":null,"abstract":"The power-boosted laser transmitted via a fiber tip sinusoidally excites the target trace molecules, generating a photothermal (PT) effect. The Gaussian-distributed plane wave heats the medium adjacent to the Fresnel reflection surface. Meanwhile, a continuous probe light traverses the heating field, and the periodic temperature change then modulates the phase of the probe light. A multi-beam interferometer formed by aligning the Fresnel reflection surface to a gold-coated high-reflection surface possesses high resolution and sensitivity, significantly enhancing the detection performance. A well-established theoretical model of instantaneous PT transduction and optical phase modulation is employed to obtain the optimized interferometric configuration. To validate the effective interferometric phase transformation within the cavity, a comparison is made between the simple silicon cavity and the gold-coated cavity. The limitation of detection of such extrinsic fiber-tip PT sensors indicates one magnitude lower as compared to the conventional PT interferometric gas sensor with such robust and compact sensing designs. This work lays a solid foundation for future research on gas laser phase modulators and nonlinear laser–matter interactions.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"63 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Larissa Boie, Benjamin H. Strudwick, Rafael T. Winkler, Yunpei Deng, Steven L. Johnson
We present an experimental implementation of a chirped mid-infrared (mid-IR) high-power laser source with variable center frequency between 4 and 30 THz and continuously tunable frequency sweep of up to 20% within one pulse, with a pulse duration of 2 ps. The peak electric field obtained at 4 THz is 1.5 MV/cm. We generate the mid-IR light using a difference-frequency generation process with two phase-locked, chirped IR pulses. The obtained mid-IR electric field waveform is characterized using electro-optic sampling. We compare our experimental results with the predictions of numerical simulations. The results indicate the potential for efficient driving of vibrational modes into a strongly anharmonic regime, in cases where using Fourier-transform-limited pulses to achieve similar vibrational amplitudes would lead to dielectric breakdown.
{"title":"High-power femtosecond mid-IR source with tunable center frequency and chirp","authors":"Larissa Boie, Benjamin H. Strudwick, Rafael T. Winkler, Yunpei Deng, Steven L. Johnson","doi":"10.1063/5.0234867","DOIUrl":"https://doi.org/10.1063/5.0234867","url":null,"abstract":"We present an experimental implementation of a chirped mid-infrared (mid-IR) high-power laser source with variable center frequency between 4 and 30 THz and continuously tunable frequency sweep of up to 20% within one pulse, with a pulse duration of 2 ps. The peak electric field obtained at 4 THz is 1.5 MV/cm. We generate the mid-IR light using a difference-frequency generation process with two phase-locked, chirped IR pulses. The obtained mid-IR electric field waveform is characterized using electro-optic sampling. We compare our experimental results with the predictions of numerical simulations. The results indicate the potential for efficient driving of vibrational modes into a strongly anharmonic regime, in cases where using Fourier-transform-limited pulses to achieve similar vibrational amplitudes would lead to dielectric breakdown.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"67 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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