Laser Physics Letters最新文献

{"title":"Quantum tomography of a photon-number-resolving detector based on continuous time multiplexing: memory effect","authors":"G V Avosopiants, K G Katamadze, N A Borshchevskaia, Yu I Bogdanov, S P Kulik","doi":"10.1088/1612-202x/ad6e69","DOIUrl":"https://doi.org/10.1088/1612-202x/ad6e69","url":null,"abstract":"We address the characterization of a photon-number-resolving detector based on continuous time multiplexing. We develop and verify a mathematical model of this detector and explore various approaches to its quantum tomography. Additionally, we encounter a memory effect and discuss the feasibility of describing this type of detector using a transfer matrix or positive operator-valued measure (POVM) decomposition.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"A novel semiquantum key distribution protocol with Bell states","authors":"Zhenying Sun","doi":"10.1088/1612-202x/ad59fe","DOIUrl":"https://doi.org/10.1088/1612-202x/ad59fe","url":null,"abstract":"In this paper, a novel semiquantum key distribution (SQKD) protocol is proposed using Bell states, where quantum Alice can share secret bits with semiquantum Bob via a quantum channel. Semiquantum Bob is required to measure particles with the basis (i.e. ), produce fresh particles within the basis and send particles via a quantum channel. Security analysis turns out that this protocol is immune to various attacks launched by the outside eavesdropper. Compared with present SQKD protocols using Bell states without a third party (Sun et al 2011 arXiv:1106.2910v3; Wang et al 2011 Chin. Phys. Lett.28 100301; Wu et al 2022 Front. Phys. 10 1029262), on the one hand, this protocol has the highest qubit efficiency; and, on the other hand, the reflecting operations of the semiquantum user in this protocol contribute to the generation of final shared keys.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Power scaling of intra-cavity Nd:YAG/LBO laser at 532 nm by birefringence compensation","authors":"Shuai Li, Zijun Fang, Majun Peng, Zhanda Zhu, Hong Lei, Qiang Li","doi":"10.1088/1612-202x/ad59fa","DOIUrl":"https://doi.org/10.1088/1612-202x/ad59fa","url":null,"abstract":"We report an effective method to reduce the impact of polarization state changes caused by thermal birefringence in intra-cavity frequency-doubled laser. The laser consists of a diode side pumped Nd:YAG module, an acousto-optic modulator Q-switch, and an LBO crystal used for SHG generation in 532 nm laser. The effect of thermal birefringence originated by the Nd:YAG rod with concave-shape end surfaces on SHG efficiency is compensated by the insertion of a <italic toggle=\"yes\">λ</italic>/8 plate into the cavity. At the repetition frequency of 9 kHz, the 532 nm laser achieves a maximum output power of 23.8 W, a pulse duration of 60 ns (FWHM), and a beam quality factor of <italic toggle=\"yes\">M_x\u0000²\u0000</italic>× <italic toggle=\"yes\">M_y\u0000²\u0000</italic> = 1.52 × 1.43. Compared with the <italic toggle=\"yes\">λ</italic>/4 plate and without plate, the maximum average power of the laser with the <italic toggle=\"yes\">λ</italic>/8 plate has increased by 22.7% and 66.4%, respectively, the beam quality factor has also been greatly improved correspondingly. This method provides a new solution for lasers to compensate thermally induced birefringence.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141572833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Mode-selective photon-added two-mode squeezed vacuum state and its entanglement properties","authors":"Heng-Mei Li, Zhen Wang, Jian-Wen Cai, Hong-Chun Yuan and Xue-Xiang Xu","doi":"10.1088/1612-202x/ad59f9","DOIUrl":"https://doi.org/10.1088/1612-202x/ad59f9","url":null,"abstract":"A class of non-Gaussian entangled states is introduced by applying the nonlocal single-photon addition to two-mode squeezed vacuum state and the properties of entanglement are numerically investigated according to linear entropy and Einstein–Podolsky–Rosen (EPR) steering. After the nonlocal single-photon addition operation, Wigner function of the generated state appears some negative region and loses its Gaussian property in phase space. In essence, non-Gaussian entangled states are generated after applying nonlocal single-photon addition. Additionally, by studying the linear entropy and EPR steering, we find that single-photon addition can enhance their entanglement degree and non-Gaussian steering can be witnessed in a large range of squeezing parameter for the second-order quadratures, which may provide a well application in the fields of quantum information processing.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Computationally efficient adaptive optimization of vector-method parameters for phase-sensitive strain estimation in optical coherence elastography","authors":"Alexey A Zykov, Alexander L Matveyev, Lev A Matveev, Maher Assaad and Vladimir Y Zaitsev","doi":"10.1088/1612-202x/ad552c","DOIUrl":"https://doi.org/10.1088/1612-202x/ad552c","url":null,"abstract":"A new method for automatic adaptive optimization of strain estimation in phase-sensitive optical coherence tomography (OCT) is introduced. More specifically, this paper focuses on optimizing the estimation of strain using the vector method, in which OCT signals are treated as vectors in the complex plane. In phase-sensitive optical coherence elastography, the tissue strain is extracted from the interframe phase variation between the complex-valued scans acquired for the initial and deformed tissue. This phase variation is proportional to interframe displacements of scatterers and corresponds to the argument of the pixel-by-pixel product of the initial OCT scan and complex-conjugate deformed scan. Measurement noises and the so-called ‘speckle noise’ that are intrinsic to OCT scans cause degradation of the derived scan obtained by such multiplication. To mitigate the noise influence, complex-valued pixel amplitudes in the derived scan are usually averaged over a certain window. The interframe strain is found by estimating the gradient of the interframe phase difference. The noise influence on the strain estimation can also be reduced by increasing the scale over which the phase-variation gradient is estimated. However, choosing a too large window for preliminary averaging may significantly distort the reconstructed strain distribution. Similarly, a too large scale for gradient estimation may also cause errors in the estimated-strain magnitude and even its sign (because of possible phase wrapping). Therefore, appropriately performed adaptive choice of the strain-estimation parameters can greatly improve the quality of strain estimation. Here, we present a unified approach for adaptive choice of both the averaging-window size and gradient-estimation scale that were initially considered separately. The new method is computationally simplified but enables approximately the same strain-estimation quality, as demonstrated using both simulated and experimental OCT data.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Pulsating dynamics of noise-like pulses in a fiber laser with nonlinear optical loop mirror","authors":"Xude Wang, Kaixin Li, Mengxiang Lu, Yuhan Fan, Mingzhu Fu, Aijia Xu and Suwen Li","doi":"10.1088/1612-202x/ad59f8","DOIUrl":"https://doi.org/10.1088/1612-202x/ad59f8","url":null,"abstract":"We experimentally investigate the nature of pulsating noise-like pulses (NLPs) in a fiber laser based on the nonlinear optical loop mirror. By adjusting the intra-cavity polarization, three types of pulsating NLPs can be obtained in the cavity. By utilizing the dispersive Fourier transformation technique, the real-time evolution dynamics of NLP pulsation have been investigated in detail. Different from the conventional pulsating behavior, the NLPs undergo remarkable and periodical variations in their width with slight changes in pulse peak powers during pulsation process. We speculate that the wavelength-dependent gain saturation is involved in the pulsating NLP evolution. Quasi-periodic energy oscillations are associated with cyclic generation and subsequent walkoff of wavelength-shifted components, resulting in the different pulsating dynamics of NLP. Moreover, during pulsation process, the NLP splitting could happen with the increasing of energy. All these findings will help to complement our understanding of NLP pulsation in a fiber laser.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Peculiarities of the intrinsic symmetry of linear and nonlinear optical susceptibility tensors in nonabsorbing inhomogeneous media with nonlocality of optical response","authors":"P S Ryzhikov and V A Makarov","doi":"10.1088/1612-202x/ad51e4","DOIUrl":"https://doi.org/10.1088/1612-202x/ad51e4","url":null,"abstract":"We show that using the Landau–Lifshitz form of the constitutive equations to construct electrodynamics of inhomogeneous nonabsorbing media with nonlocality of optical response leads to previously unknown intrinsic symmetry relations of the spatially dependent tensors of local and nonlocal optical susceptibilities guaranteeing that the energy conservation law is fulfilled. The discovered relations drastically differ from the analogous relations for homogeneous spatially dispersive media and make it possible to correctly write down the balance equation for the energy conservation law in inhomogeneous media with nonlocality of optical response without the previously accepted artificial addition of any new terms to the classical constitutive equations suggested by Landau and Lifshitz.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Average coherence and average correlated coherence as indicators of quantum phase transitions in the XY model with staggered Dzyaloshinskii-Moriya interaction","authors":"Gan-Lu Li and Yu-Xia Xie","doi":"10.1088/1612-202x/ad59fd","DOIUrl":"https://doi.org/10.1088/1612-202x/ad59fd","url":null,"abstract":"The performance of average coherence (AC) and average correlated coherence (ACC) in detecting quantum phase transitions (QPTs) has been explored by considering the XY model with staggered Dzyaloshinskii-Moriya interaction. By using the quantum renormalization group method, it is shown that the ground-state AC and ACC show either a maximum or a minimum at the QPT point. Moreover, the AC and ACC susceptibilities (i.e. their derivatives with respect to the driving parameter) have two extreme points near the two sides of the QPT point. A finite-scaling analysis reveals that these extreme points tend to the QPT point after several iterations of the renormalization and the susceptibilities at the QPT point become divergent in the thermodynamic limit.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Bell inequality violation in relativity theory","authors":"A V Belinsky and I I Dzhadan","doi":"10.1088/1612-202x/ad552d","DOIUrl":"https://doi.org/10.1088/1612-202x/ad552d","url":null,"abstract":"A violation of Bell local realism inequalities in Clauser–Horne–Shimony–Holt form has been discovered in a relativistic Gedankenexperiment. This means that there are no definite joint probabilities and this finds a classical explanation in the structure of special relativity. The discovered nonlocality is weaker than Albert Einstein’s quantum ‘spooky action at a distance’, and its presence suggests certain parallels between special relativity and quantum mechanics.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Cryptographic computer generated hologram watermarking technology based on DWT-SVD","authors":"Songxiao Liu, Nana Yu, Xiangxiang Ji, Danying Song, Sixing Xi, Zhuqing Zhu, Xiaolei Wang and Liying Lang","doi":"10.1088/1612-202x/ad51e3","DOIUrl":"https://doi.org/10.1088/1612-202x/ad51e3","url":null,"abstract":"To improve the security and invisibility of image encryption and concealment, an encrypted computer generated hologram (CGH) watermarking technology based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is proposed. Firstly, the image to be encrypted is encoded and converted into a binary real-valued CGH. The encrypted CGH is then embedded into the host image as a watermark, implementing image encryption and concealment. During decryption, the encrypted CGH watermark is first extracted using the inverse DWT-SVD and the correct keys. Subsequently, the decrypted image is obtained by applying the correct optical key for computational holographic reproduction. The method introduces computational holographic coding and optical keys into the digital watermarking technique and combines the characteristics of DWT and SVD, solving the problem of the high false positive rate of the SVD algorithm. Simulation results show that the security of image encryption and concealment is greatly improved with the introduction of CGH into watermarking technology, especially in terms of robustness to watermark attacks and noise. This method can be applied in the fields of copyright protection and anti-counterfeiting for digital and printed images.","PeriodicalId":17940,"journal":{"name":"Laser Physics Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141501483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}