International School on Quantum Electronics: Laser Physics and Applications最新文献

Formation of cesium dimers and observation of high-resolution dimer spectra in spatially restricted Cs vapor 铯二聚体在空间限制铯蒸气中的形成及高分辨率二聚体光谱的观测

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2516749

P. Todorov, T. Vartanyan, G. Pichler, A. Sargsyan, D. Sarkisyan, S. Cartaleva

引用次数: 2

Radiation generation via non-linear optical processes during propagation of high peak and high average power fs pulses 高峰值和高平均功率fs脉冲传播过程中非线性光学过程产生的辐射

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2515880

S. Fourmaux, P. Lassonde, J. Kieffer, F. Théberge, M. Châteauneuf, E. Hallin

引用次数: 1

Depolarization of femtosecond pulses in air by nonlinear mechanisms 非线性机制下飞秒脉冲在空气中的去极化

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2519307

D. Georgieva

引用次数: 0

Synthesis of submicron-dispersed carbon phases in water by Nd:YAG laser ablation of graphite Nd:YAG激光烧蚀石墨在水中合成亚微米分散碳相

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2516582

A. Nikolov, I. Balchev, N. Stankova, I. Avramova, E. Valcheva, S. Russev, D. Karashanova, B. Georgieva, I. Kostadinov, J. Mladenoff, S. Kolev, T. Milenov

{"title":"Synthesis of submicron-dispersed carbon phases in water by Nd:YAG laser ablation of graphite","authors":"A. Nikolov, I. Balchev, N. Stankova, I. Avramova, E. Valcheva, S. Russev, D. Karashanova, B. Georgieva, I. Kostadinov, J. Mladenoff, S. Kolev, T. Milenov","doi":"10.1117/12.2516582","DOIUrl":"https://doi.org/10.1117/12.2516582","url":null,"abstract":"Mixtures of micron to submicron complex carbon phases, namely, defective graphene, graphene-like (multi-layered graphene, graphene oxide etc.), graphite flakes etc. as fine suspensions were obtained by pulsed laser ablation of highly purified microcrystalline graphite targets immersed in double distilled water. The fundamental wavelength (λ = 1064 nm) and the fourth harmonic (λFHG = 266 nm) of a Nd:YAG laser system (15 ns pulse duration, 10 Hz pulse repetition rate) were used in the fabrication process. The laser fluence value corresponding to the onset of the ablation process, the one initiating optical breakdown in water and an intermediate value were used for each of the wavelengths mentioned above. The morphology of the particles dispersed in water was studied by scanning electron microscopy (SEM). Their phase composition and structure were explored by Raman spectroscopy. It showed the presence of some traces of polymerized hydrocarbons (polystyrene, polybutadiene etc.) in addition to the main carbon phases: defected graphene, reduced graphene oxide and graphite.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127951830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Perspective laser medium for random lasing 随机激光透视激光介质

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2516744

H. Kisov, G. Dyankov, V. Strijkova, B. Georgieva, V. Serbezov

{"title":"Perspective laser medium for random lasing","authors":"H. Kisov, G. Dyankov, V. Strijkova, B. Georgieva, V. Serbezov","doi":"10.1117/12.2516744","DOIUrl":"https://doi.org/10.1117/12.2516744","url":null,"abstract":"Random lasers are a novel disorder-based laser light source with many photonics applications. In the present work we study the optical properties of a new unordered medium consisted of an epoxy resin as matrix with dissolved different binary solutions of Rhodamine 6G and Rhodamine B. The choice of these dyes is related to their great application in laser physics. A detailed study of the spectral dependence of fluorescence is performed. The spontaneous emission is very intensive and follows the spectral dependence of dyes transmission and exceeds 750 nm. The threshold of the laser medium is 1.6 mJ for 10 ns pulse at second harmonics of Nd:YAG laser, and full width at half maximum (FWHM) is around 1.5 nm. Slope efficiency of the medium is 16%. The laser generation without resonator was studied also and lasing emission at 597 nm was observed. The fact can be explained by random lasing provided by the medium. This is in good relation and in accordance with the intensive scattering inherent to the medium which is registered. Not used additional scatter centers such as ZnO nanorods or Ag, Al, Al2O3, TiO2 agglomerates and others in our experiments.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115828533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Powerful high-beam-quality sealed-off laser system oscillating in middle infrared spectral range on strontium atomic transitions for medical applications 强大的高光束质量的封闭激光系统振荡在中红外光谱范围内的锶原子跃迁医疗应用

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2516357

I. Kostadinov, S. I. Slaveeva, K. Temelkov

引用次数: 2

Spectral line narrowing due to velocity selective optical pumping on the D2 line hyperfine transitions in spatially restricted Cs vapor 空间受限Cs蒸气中D2线超精细跃迁的速度选择性光泵浦导致光谱线变窄

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2517547

C. Andreeva, T. Vartanyan, P. Todorov, G. Todorov, S. Cartaleva

{"title":"Spectral line narrowing due to velocity selective optical pumping on the D2 line hyperfine transitions in spatially restricted Cs vapor","authors":"C. Andreeva, T. Vartanyan, P. Todorov, G. Todorov, S. Cartaleva","doi":"10.1117/12.2517547","DOIUrl":"https://doi.org/10.1117/12.2517547","url":null,"abstract":"We report on the investigation of narrow sub-Doppler-width resonances observed at the D2 line of Cs atoms (Fg = 4 → Fe = 3, 4, 5 hyperfine transitions), confined in thin optical cells. These cells have a thickness of L = 6λ (λ = 852 nm) and L = 700 μm, and are irradiated by two narrow-band laser radiations (one with fixed and the other with scanned frequency). We show that for zero frequency detuning of the fixed-frequency laser from the Fg = 4 → Fe = 5 hyperfine transition, its absorption spectrum in the thin cell consists of resonances, centered at the respective hyperfine transitions. The spectral widths of these resonances range from 2 to 20 MHz, and they are characterized by a good contrast and extremely small Doppler background. This spectrum is highly sensitive to the frequency offset of the fixedfrequency laser. The analysis leads to the conclusion that the spatial restriction of Cs vapor suppresses the interaction of the light with atoms with significant velocity component along the direction of the laser beam propagation.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133096009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Monitoring of a drying process in polymer water and methanol solutions by dynamic speckle metrology 用动态散斑测量法监测聚合物水和甲醇溶液中的干燥过程

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2516355

E. Stoykova, B. Blagoeva, T. Nikova, D. Nazarova, L. Nedelchev

{"title":"Monitoring of a drying process in polymer water and methanol solutions by dynamic speckle metrology","authors":"E. Stoykova, B. Blagoeva, T. Nikova, D. Nazarova, L. Nedelchev","doi":"10.1117/12.2516355","DOIUrl":"https://doi.org/10.1117/12.2516355","url":null,"abstract":"Observation of speed of processes by dynamic speckle metrology has been applied to different samples of industrial or biological nature. The method allows for detecting regions of lower or higher activity on the sample surface through statistical processing of the speckle patterns formed on this surface under laser illumination. The aim of the paper is to check applicability of this dynamic speckle technique for monitoring of the drying process in polymer water and methanol solutions. For the purpose, we recorded several sets of 256 correlated in time speckle patterns of a transparent drop of PAZO water solution and PAZO methanol solution on a glass plate illuminated by a He-Ne laser. The sets were separated by intervals of several minutes, and the last set was recorded 100 minutes after the start of the experiment. For statistical description of activity on the observed sample we applied pointwise correlation-based algorithms to binary patterns formed by comparison of intensities at each point to a sign threshold. The obtained two-dimensional maps of the used statistical estimator at different time lags clearly indicated the difference between water and methanol solutions and proved efficiency of dynamic speckle analysis for monitoring of drying processes in polymer solutions.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131312723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Towards bridging non-ionizing, ultra intense, laser radiation and ionizing radiation in cancer therapy 非电离、超强、激光和电离辐射在癌症治疗中的桥梁作用

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2518241

A. Serafetinides, M. Makropoulou

{"title":"Towards bridging non-ionizing, ultra intense, laser radiation and ionizing radiation in cancer therapy","authors":"A. Serafetinides, M. Makropoulou","doi":"10.1117/12.2518241","DOIUrl":"https://doi.org/10.1117/12.2518241","url":null,"abstract":"In oncology, cancer radiotherapy is a well-established therapeutic technique for more than 100 years and, worldwide, about two-thirds of all cancer patients will undergo conventional X-rays or gamma-rays therapy, as monotherapy or as part of their treatment, to destroy tumor cells by damaging their DNA. As the high energy electromagnetic waves based radiotherapy is not equally effective in all types and location of cancerous tumors, radiotherapy using accelerator based hadron beams is a well-established alternative, especially for deep-placed tumors, as a result of the well-known Bragg peak phenomenon. External proton beam radiation therapy is most commonly used in the treatment of pediatric, central nervous system and intraocular cancers. To overcome the major obstacle of the very expensive proton production facilities (through accelerators) in building of proton cancer treatment medical centers, the use of high-power lasers for particle radiation production was proposed. The recent development of lasers with ultrashort pulses (e.g. with pulse lengths around 30 fs) resulted in particle acceleration from the rear side of a laser-irradiated thin foil, based on their unique properties and laser-matter interaction mechanisms. In this review work, we aim to present the progress toward laser-driven radiotherapy, as well as to discuss if and how the radiobiological effectiveness of particle radiation generated by lasers differs from that provided by other conventional techniques. We will discuss the expectations and limitations in anti-cancer laser-driven proton therapy, reported in literature over the last decade. In the framework of the national project HELLAS-CH, we will present some of the preliminary efforts on the combined photodynamic and ionizing radiation action, with ultra-fast laser pulses, on tissue simulators and biological samples.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114319466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Competitive light wavelength division multiplexing element based on tunable interference wedged structures 基于可调谐干涉楔形结构的竞争光波分复用元件

International School on Quantum Electronics: Laser Physics and Applications Pub Date : 2019-01-29 DOI: 10.1117/12.2516698

M. Nenchev, M. Deneva, E. Stoykova

{"title":"Competitive light wavelength division multiplexing element based on tunable interference wedged structures","authors":"M. Nenchev, M. Deneva, E. Stoykova","doi":"10.1117/12.2516698","DOIUrl":"https://doi.org/10.1117/12.2516698","url":null,"abstract":"Interference Wedged Structure (IWS) is an optical element with useful properties for optical metrology, spectral analysis and optical communications. We have introduced in the paper a new perspective element of this type – Composite Tunable Interference Wedged Structure (CTIWS). The CTIWS is list-like sequence of superimposed wedged layers each with reflecting surfaces. For conveniently chosen apex angles and thicknesses of the layers, the CTIWS can assure high spectral selectivity to 0.01nm within a spectral range of 10 nm and more at smooth tunability by simple sliding of the structure along the wedge arm (a few cm). We have developed simple physical description of the IWS and CTIWS by adapting Fabry-Perot theory. We show that for the most important practical cases the results are similar to the obtained by more complex exact analytical description. The theoretical predictions are confirmed by experimental results. On the base of IWS and CTIWS combined in a suitable architecture, we have introduced and studied a new lossless Wavelength Division Multiplexing (WDM) element with independent tuning of each output/input. We considered the WDM implementation for the case of fiber optical systems used in optical communications.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114806313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3