Applied Physics B最新文献

{"title":"Orientation-dependent high harmonic generation in ZnO","authors":"Tzveta Apostolova,&nbsp;Balint Kiss,&nbsp;Deborata Rajak,&nbsp;Katalin Pirisi,&nbsp;Rajaram Shrestha,&nbsp;Levente Abrok,&nbsp;Boyan Obreshkov,&nbsp;Jean Claude Kieffer,&nbsp;Dimitar Velkov,&nbsp;Miles Thoma","doi":"10.1007/s00340-026-08680-7","DOIUrl":"10.1007/s00340-026-08680-7","url":null,"abstract":"<div><p>We theoretically and experimentally investigate orientation-dependent high-harmonic generation (HHG) in zinc oxide subjected to intense femtosecond mid-infrared (MIR) laser pulses. In agreement with past measurements from literature, we observe non-perturbative harmonic spectra with harmonics extending beyond the material band gap. The spectra depend sensitively on the orientation of the crystal with respect to the laser polarization direction. To benchmark the measurements, we performed detailed theoretical calculation of the orientation-dependent harmonic yields. The theory predicts a six-fold angular modulation of the intensity of odd-order harmonics in the (0001)-plane, which can be deduced from the symmetry of the hexagonal lattice alone, in contrast a four-fold symmetry is observed in the experiment. The theory points out the essential role of the anisotropy of the multiple band structure affecting the dynamics of electron–hole pair excitation and solid-state HHG.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08680-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Green external-cavity diode lasers for Raman spectroscopy: tunability, linewidth, and performance comparison","authors":"Julia Lukaszewski,&nbsp;Enrico Dietz,&nbsp;Susanne Schröder,&nbsp;Maximilian Buder,&nbsp;Heinz-Wilhelm Hübers","doi":"10.1007/s00340-026-08692-3","DOIUrl":"10.1007/s00340-026-08692-3","url":null,"abstract":"<div><p>The implementation and characterization of green external cavity diode lasers (ECDL) in Littrow configuration is presented. It is specifically developed for Raman spectroscopy. Eight distinct green laser diodes are systematically characterized and compared: six broad-area diodes and two transverse single-mode diodes. All diodes achieve wide tuning ranges between 8 nm and 12 nm and output powers of more than 100 mW. One of the transverse single-mode diodes reached 45 mW maximum output power, which is sufficient for Raman measurements. Preliminary Raman measurements using a broad-area diode laser demonstrate the feasibility of this ECDL setup for spectroscopic applications.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08692-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical characterization by a fiber-optic system of UV-induced refractive index modulation in gelatin–methacrylamide hydrogels","authors":"Jakub Czubek,&nbsp;Patryk Sokołowski,&nbsp;Krzysztof Słowiński,&nbsp;Maciej Wróbel,&nbsp;Paweł Wityk,&nbsp;Małgorzata Szczerska","doi":"10.1007/s00340-026-08688-z","DOIUrl":"10.1007/s00340-026-08688-z","url":null,"abstract":"<div><p>Photopatternable hydrogels with controllable refractive index (RI) have gained increasing attention as a tool for biophotonic calibration, optical phantoms, and studies of light–matter interaction in soft matter. Here, we investigate UV-induced photopolymerization in gelatin-methacrylamide (MAM) hydrogels as a low-toxicity, optically transparent platform enabling spatial RI modulation. The hydrogels were synthesized using non- or low-toxic components and characterized by fiber-optic refractometry, validated against an Abbe refractometer with deviations below 1%. UV irradiation at 365 nm produced controlled RI modulation within the biologically relevant range of 1.32–1.36 at 1310 nm, exhibiting a reproducible parabolic RI–time dependence (R² = 0.996). Dynamic light scattering and Raman spectroscopy reveal that residual dissolved oxygen may inhibit early-stage photopolymerization, leading to reduced hydrodynamic polymer dimensions and a nonlinear optical response at short exposure times. Following oxygen depletion, polymer growth proceeds uniformly, resulting in a predictable increase of RI with irradiation time. These results establish gelatin-MAM hydrogels as a physically accessible system for refractive index engineering in soft matter. The demonstrated optical tunability and transparency make this platform suitable for biophotonic phantoms, fiber-optic sensing validation, and investigations of photochemically driven refractive index modulation in hydrated materials.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08688-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing insect monitoring: analysis of mel-frequency cepstral coefficients from optical signals for body orientation estimation","authors":"Topu Saha,&nbsp;Benjamin P. Thomas","doi":"10.1007/s00340-026-08683-4","DOIUrl":"10.1007/s00340-026-08683-4","url":null,"abstract":"<div><p>Entomological photonic sensors enable continuous, automated and non-invasive monitoring of flying insects by recording optical signals of insects transiting in their field-of-view. These instruments can observe extremely large numbers of insects and provide ecological measurements such as aerial density [insect/m³] and biomass density [mg/m³] with temporal resolution down to a minute and minimal downtime. Nevertheless, their taxonomic resolution is limited; since deriving reliable taxonomic signatures from optical signals is difficult, knowing insects represent the most species-rich group of organisms. In this study, we focus on the influence of body orientation during transit, a factor that directly impacts how the body and wings contribute to the recorded signal. Using numerical simulations based on a 3D model of an <i>Apis mellifera</i> (honeybee), and laboratory experiments with <i>Musca domestica</i> (housefly), we analyze extinction signals using Mel-Frequency Cepstral Coefficients. They characterize the time-frequency structure of the waveform, caused by changes in orientation of an insect as it crosses the beam. A Gaussian Process regression model trained on these coefficients predicts symmetry-reduced orientation angles with high accuracy. By correcting for orientation, we can retrieve a more accurate estimate of the insect’s body optical cross-section. This correction may lead to improved identification and mass estimation. Our simulation results show that orientation effects can alter apparent cross-sections by up to 83% in this particular case, however this may be even more pronounced for insects with elongated bodies, underscoring the importance of accounting for them in biomass calculations obtained from photonic sensors. These findings demonstrate that orientation-sensitive signal analysis can refine predictor variables and improve the reliability of photonic sensors in providing ecological metrics beyond abundance, paving the way toward higher taxonomic resolution.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13212683/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148051755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy transfer from ultra-short laser pulse to quantum oscillator in thermal equilibrium","authors":"V. A. Astapenko,&nbsp;E. V. Sakhno,&nbsp;S. V. Sakhno","doi":"10.1007/s00340-026-08690-5","DOIUrl":"10.1007/s00340-026-08690-5","url":null,"abstract":"<div><p>We propose a simple analytical approach for description of energy transfer from ultra-short laser pulses to quantum oscillator in the thermal equilibrium based on approximate expression for oscillator spectral function. Formulas for the probability of energy transfer in the limits of high and low temperatures are derived and analyzed. The characteristic features of energy transfer to a quantum oscillator from unipolar pulses, wavelets and multi-cycle laser pulses are established.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08690-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryogenically cooled yb: KGW regenerative amplifie","authors":"Jinwei Gu,&nbsp;Jun Yu,&nbsp;Zhe Zhang,&nbsp;Zhuoran Li,&nbsp;Yifeng Ye,&nbsp;Qingyue Cui,&nbsp;Han Kong,&nbsp;Hanlin Xu,&nbsp;Yongcheng Zhong,&nbsp;Famei Wang,&nbsp;Qingdian Lin,&nbsp;Jie Xu,&nbsp;Cangtao Zhou,&nbsp;Shuangchen Ruan,&nbsp;Xiaoyang Guo","doi":"10.1007/s00340-026-08643-y","DOIUrl":"10.1007/s00340-026-08643-y","url":null,"abstract":"<div><p>We develop a diode-pumped cryogenically cooled Yb: KGd(WO₄)₂ (Yb: KGW) crystal regenerative amplifier (RA). At 77 K, it delivers 1.28 mJ output pulses with 2.9 nm spectral bandwidth and output power stability of 0.7% at a 1 kHz repetition rate. The amplified beam demonstrates near-diffraction-limited quality, exhibiting M² factors of 1.01 and 1.01 in the horizontal and vertical directions, respectively. To our best knowledge, this is the first cryogenically cooled Yb: KGW crystal RA.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08643-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of electronic defect states in sb2se3 thin films: ımpact of phase transition and environmental aging","authors":"Ayten Cantas,&nbsp;Gokhan Yilmaz","doi":"10.1007/s00340-026-08686-1","DOIUrl":"10.1007/s00340-026-08686-1","url":null,"abstract":"<div><p>Antimony selenide (Sb₂Se₃) is a promising photovoltaic material due to its high absorption coefficient and favorable mobility. However, its long-term stability and defect dynamics remain insufficiently explored. In this study, Sb₂Se₃ thin films were fabricated via magnetron sputtering, with post-deposition annealing used to induce a transition from an amorphous (Sb-1 film) to a crystalline orthorhombic phase (Sb-2 film). We systematically investigated the impact of ambient air, oxygen, UV irradiation, and light-soaking on the electronic properties of these films. Key findings reveal that oxygen exposure increases dark conductivity (σ_D) by approximately one order of magnitude, a process largely reversible under vacuum for both phases. In contrast, radiative aging induced divergent responses: while amorphous film showed transient responses, crystalline samples exhibited complex and partially irreversible defect dynamics. Specifically, UV irradiation and long-term atmospheric exposure induced permanent shifts in the mobility-lifetime (mt) product of crystalline film, indicating alterations in dominant recombination pathways. Furthermore, mt products increased during light-soaking, suggesting the activation of metastable states. These results provide critical insights into phase-dependent environmental sensitivity, highlighting that precise crystallinity control and encapsulation are paramount for Sb₂Se₃ device stability.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08686-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of self-mixing in THz quantum cascade lasers under varying mode dynamics and external optical feedback","authors":"Novak Stanojević,&nbsp;Nikola Vuković,&nbsp;Milan Ignjatović,&nbsp;Nikola Basta,&nbsp;Jelena Radovanović","doi":"10.1007/s00340-026-08682-5","DOIUrl":"10.1007/s00340-026-08682-5","url":null,"abstract":"<div><p>In this work, a set of effective semiconductor Maxwell–Bloch equations has been used to study the dynamics of a bound-to-continuum terahertz quantum cascade laser (QCL) under external optical feedback at both threshold and maximum operating currents. The used model is extended to include current-dependent input parameters obtained from density matrix transport simulations, enhancing physical accuracy and enabling device-specific modelling within the relevant current range for a specific fabricated QCL. Near threshold, external feedback shifts the emission from single-mode to multimode and, depending on the external cavity length, can produce different dynamical regimes. The feedback-induced reduction of the threshold current is demonstrated and quantified. At maximum operating current, the laser is inherently multimode, with external feedback producing different dynamical regimes. The model predicts high sensitivity of output power to variations in the external cavity. When operating with a few modes, the output remains interpretable for sensing applications, whereas highly multimode emission leads to noisy, less interpretable signals. This framework provides insight into self-mixing and mode competition phenomena, aiding in the identification of QCL designs that minimise multimode behaviour for reliable THz sensing and has a direct impact on the advancement of QCL-based sensing and communication applications.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08682-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148008978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data transmission rate estimates for OAM-carrying millimetre waves generated by rectangular arrangements of discrete radiating sources","authors":"Andjelija Ž. Ilić,&nbsp;Jelena Z. Trajković,&nbsp;Slobodan V. Savić,&nbsp;Milan M. Ilić","doi":"10.1007/s00340-026-08689-y","DOIUrl":"10.1007/s00340-026-08689-y","url":null,"abstract":"<div><p>Millimetre-waves and optical waves carrying orbital angular momentum (OAM) are foreseen to be among the key technological enablers of beyond-5G and 6G communication systems. Discrete OAM EM wave source arrangements, such as the large antenna arrays or smaller distributed radiating surfaces, offer the advantages of cost-effectiveness, seamless OAM mode reconfiguration, and multiplexing of different OAM modes through a single aperture. Since their performances generally improve with the use of electrically larger sources, the use of narrow, elongated rectangular sources might be more convenient for some applications than the use of large circular discrete source arrangements. However, adjusting the structure and parameters of sources that are not entirely symmetric is not straightforward. The influence of asymmetry on the data transmission rates of OAM-based communication systems has not yet been investigated. Using computational modelling based on the short dipole method, we study the OAM EM wave generation by rectangular sources, propose a simple adjustment of sources resulting in a reasonably good OAM mode phase and magnitude patterns, and compare data transmission rates of rectangular and circular antenna arrays. Our analysis confirmed the suitability of the considered discrete sources for utilization in short-range data transmission systems.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08689-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on high dynamic range 3D measurement method based on polarization phase-shifting fringes and geometric constraints","authors":"Can Wang,&nbsp;Xianwu Xiao,&nbsp;Guochi Wang,&nbsp;Yao Liu,&nbsp;Pengjin Lang,&nbsp;Weize Wang,&nbsp;Keran Deng,&nbsp;Maohua Jiang,&nbsp;Nagendra Parasad Yadav","doi":"10.1007/s00340-026-08679-0","DOIUrl":"10.1007/s00340-026-08679-0","url":null,"abstract":"<div><p>Aiming at the problems of fringe modulation degradation and phase unwrapping relying on extra coding and being easily affected by fringe quality in high dynamic range (HDR) scenes in 3D measurement of HDR objects, this paper proposes an HDR object 3D measurement method (G-PPSF) fusing polarization phase-shifting modulation and geometric prior constraints. Based on the Stokes-Mueller polarization optics theory, this method constructs a polarization phase-shifting projection model under extremely small incident angle, and designs a (2<i>N</i> + 2)-frame compact projection sequence. It can suppress fringe distortion caused by surface reflectivity difference with a single exposure, and achieve high-quality wrapped phase acquisition in HDR scenes. Geometric prior constraints are introduced to construct a virtual reference plane, which is independent of fringe intensity information and inherently robust to HDR scenes, enabling absolute phase unwrapping without projecting extra auxiliary fringes. Experimental results show that compared with traditional methods, G-PPSF can maintain a point cloud data integrity rate of more than 97% even under high noise filtering thresholds. In the plane fitting test, its root mean square error (RMSE) is stable at 0.0773 mm, and the effective data ratio is as high as 99.1%. This method does not require multi-exposure fusion or complex iterative calculation, and realizes efficient, robust and complete 3D reconstruction in HDR scenes.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08679-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}