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A Thina??Film Flexible Defecta??Mode Laser
摘要： Laser emission from a flexible defect-mode structure consisting of two photopolymerized liquid crystal thin films separated by a dye-doped polymethylmethacrylate defect layer is demonstrated. A simple and cost-effective film transfer technique is used to fabricate the flexible laser and the corresponding laser emission characteristics, which shows single-mode laser emission at λ = 582 nm, with an excitation threshold of Eth = 12.3 ± 0.5 μJ cm?2 per pulse and a slope efficiency of ηs = 6.0 ± 0.3%, are presented. The polarization state of the laser emission are also presented and are compared with the findings reported in the literature. Finally, laser-beam steering is demonstrated up to 42° by subjecting the device to a mechanically induced deformation that creates a radius of curvature of 5 mm, which is of potential interest for conformable and wearable technology platforms.
关键词： thin-film lasers,liquid crystals,flexible lasers,defect-mode lasers
更新于2025-09-23 15:19:57
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Pick and Place Distributed Feedback Lasers Using Organic Single Crystals
摘要： Organic single crystals are of interest for optoelectronic applications due to their highly ordered molecular stacking and small defect concentration, giving the possibility of high mobility and luminescence efficiency. To achieve lasing in large flat single crystals, a simple 'pick and place' method of mounting organic single crystals onto distributed feedback gratings is demonstrated. Efficient lasing is achieved with three kinds of active organic single crystals, indicating the potential for broad application of the method for making single crystal lasers using distributed feedback gratings. Detailed investigations of the anisotropic refractive index and waveguide simulations further confirm that distributed feedback can provide efficient ways of fabricating organic single crystal lasers.
关键词： organic semiconductor optoelectronics,solid-state lasers,optically pumped lasers
更新于2025-09-23 15:19:57
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New high-power 1.1-??m light source: diode-pumped continuous-wave and passively Q-switched Nd:LuYAG mixed crystal lasers
摘要： 1.1-μm laser operation has been rarely investigated in laser materials other than Nd:YAG. In this report, using a diode end pumping geometry for providing a compact, low-threshold and high-efficiency system, continuous-wave and passively Q-switched Nd:LuYAG mixed crystal lasers at 1.1 μm were demonstrated, for the first time to our knowledge. In continuous-wave mode, a maximum output power up to 6.04 W was achieved at 1112.9 nm, 1116.64 nm and 1122.65 nm with a slope efficiency of 41.8%. Wavelength tuning was obtained from 1112.05 nm to 1123.17 nm discontinuously, which has never been demonstrated in Nd:YAG lasers. Moreover, using a Cr4+:YAG saturable absorber, stable passively Q-switched laser operation was also attained with a maximum average output power up to 1.71 W. The shortest pulse width was about 37.3 ns at repetition rate of about 21.52 kHz. The maximum pulse energy was about 79.3 μJ, which is believed to be the highest pulse energy that has ever been achieved in diode-end-pumped Nd3+ lasers at this specific 1.1 μm emission band.
关键词： 1.1 μm lasers,passive Q-switching,continuous-wave,Nd:LuYAG mixed crystal
更新于2025-09-23 15:19:57
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AIP Conference Proceedings [AIP Publishing THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Karbala City, Iraq (27–28 March 2019)] THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Chaos synchronization in quantum dot semiconductor lasers with negative optoelectronic feedback
摘要： Chaos synchronization is investigated in quantum dot semiconductor lasers with negative optoelectronic feedback. Depending on the coupling strength between transmitter and receiver quantum dot semiconductor Laser. Synchronization happens when the coupling strength to the receiver matches the feedback strength to the transmitter, where the receiver output reproduces the output of the transmitter regardless of the presence of channel distortion or an encoded message. when feedback strength of transmitter, receiver quantum dot semiconductor Laser and coupling feedback strength are equal (- 0.3), time delay of transmitter, receiver quantum dot semiconductor Laser and coupling are sensitive to synchronization.
关键词： Chaos synchronization,Quantum dot semiconductor lasers,Negative optoelectronic feedback
更新于2025-09-23 15:19:57
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Complexity mapping of a photonic integrated circuit laser using a correlation-dimension-based approach
摘要： Quantifying complexity from experimental time series generated by nonlinear systems, including laser systems, remains a challenge. Methods that are based on entropy, such as permutation entropy (PE), have proven to be useful tools for the relative measure of time series complexity. However, the numerical value of PE is not readily linked to a specific type of dynamical output. Thus, the quest to calculate quantitatively meaningful fractal dimension values, such as the correlation dimension (CD), from experimental signals, is still important. A protocol for calculating minimum gradient values and their spread, an integral part of CD analysis, is used here. Minimum gradient values with small spread are presented as approximate CD values. Here-in we report mapping these values, derived from analyzing experimental time series, obtained from a 4-section photonic integrated circuit laser (PICL) across a large parameter space. The PICL is an integrated form of a semiconductor laser subject to controllable optical feedback system. The minimum gradient/approximate CD mapping shows it has some qualitatively different map regions in its dynamics as compared to a free-space-based equivalent system. We show that the minimum gradient values give insight into the dynamics even when approximate CD values cannot be determined. The agreement between the qualitative features of permutation entropy mapping and minimum gradient/approximate CD value mapping provides further support for this. Regions of time series with close to periodic and quasi-periodic dynamics are identifiable using minimum gradient value maps.
关键词： semiconductor lasers,integrated optoelectronic devices,nonlinear dynamics,complex systems,Chaos,complexity
更新于2025-09-23 15:19:57
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Flattop output extra-wide tuning range tunable laser design technique
摘要： The laser oscillator design principle, which provides extended tunability together with a flattop output in the wide spectral range, is proposed and demonstrated on the examples of the dye laser. It is realized by using an high-reflecting (HR) moving intracavity mirror (scraper) with the sharp edge partially overlapping the laser radiation in the high-Q cavity and extracting it out. The technique provides the output laser beam with M2 < 1.2 and can be applied to any type of lasers operating from the far-IR to the VUV spectral ranges. Besides, wide-band HR cavity mirrors are only used, and there are no special demands to the material of the mirror substrate.
关键词： laser efficiency,output coupler optimization,tunable lasers
更新于2025-09-23 15:19:57
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Recent advances of heterogeneously integrated III–V laser on Si
摘要： Due to the indirect bandgap nature, the widely used silicon CMOS is very inefficient at light emitting. The integration of silicon lasers is deemed as the ‘Mount Everest’ for the full take-up of Si photonics. The major challenge has been the materials dissimilarity caused impaired device performance. We present a brief overview of the recent advances of integrated III–V laser on Si. We will then focus on the heterogeneous direct/adhesive bonding enabling methods and associated light coupling structures. A selected review of recent representative novel heterogeneously integrated Si lasers for emerging applications like spectroscopy, sensing, metrology and microwave photonics will be presented, including DFB laser array, ultra-dense comb lasers and nanolasers. Finally, the challenges and opportunities of heterogeneous integration approach are discussed.
关键词： silicon photonics,heterogeneous integration,integrated circuits,lasers
更新于2025-09-23 15:19:57
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Ion acceleration with an ultra-intense two-frequency laser tweezer
摘要： Ultra-intense lasers produce and manipulate plasmas, allowing to locally generate extremely high static and electromagnetic fields. This study presents a concept of an ultra-intense optical tweezer, where two counter-propagating circularly polarized intense lasers of different frequencies collide on a nano-foil. Interfering inside the foil, lasers produce a beat wave, which traps and moves plasma electrons as a thin sheet with an optically controlled velocity. The electron displacement creates a plasma micro-capacitor with an extremely strong electrostatic field, that efficiently generates narrow-energy-spread ion beams from the multi-species targets, e.g. protons from the hydrocarbon foils. The proposed ion accelerator concept is explored theoretically and demonstrated numerically with the multi-dimensional particle-in-cell simulations.
关键词： optical tweezer,particle-in-cell simulations,plasma,ion acceleration,ultra-intense lasers
更新于2025-09-23 15:19:57
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Experimental investigations on thermal effects of a long-pulse alexandrite laser on blood vessels and its comparison with pulsed dye and Nd:YAG lasers
摘要： Laser has been widely used in the treatment of vascular skin diseases, such as port wine stain, due to the effect of selective photothermolysis in laser on biological tissue. The 755 nm alexandrite laser was expected to achieve better curative effect than the commonly used 585 or 595 nm pulsed dye laser (PDL) because of its deeper tissue penetration. In this study, the dorsal chamber model and microscopic visualization system were used to observe morphology changes on 42 blood vessels before and after irradiation with the 755 nm laser. Results showed that thermal effects of blood vessels intensified with the increase in energy, and high energy was required to produce the same thermal effect as the extension of pulse width. Different from 595 and 1064 nm lasers, partial vessel contraction was dominant thermal effect caused by the 755 nm laser. The bleeding injury rate and thermal effect of the 755 nm laser were between those of 595 nm PDL and 1064 nm Nd:YAG laser. The simulation results proved that 595 nm PDLs were effective for small and shallow target blood vessels. The 755 nm alexandrite lasers were effective in the treatment of hypertrophic and resistant blood vessels to PDL in the skin with low or moderate melanin concentration. The 1064 nm Nd:YAG laser was effective in the treatment of deeply buried and enlarged target blood vessels in the skin with high melanin concentration. The simulation results were supported by published clinical observations.
关键词： Laser therapy,Port wine stain,Vascular thermal effect,755 nm lasers
更新于2025-09-23 15:19:57
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Diode Laser Spectroscopy for Creating Effective Measuring Systems and Their Use in Biological and Medical Research
摘要： In this paper, we present the most important principles of diode laser spectroscopy, which allow one to create fundamentally new measuring systems for diverse applications in biology and medicine. Using the diode laser spectroscopy method and its primary hardware implementation the emission of gas molecules from skin of the hand was registered and ammonia skin emission was found to be dominant. The properties of exhaled air from patients in different states were determined with another special measuring complex of diode laser spectroscopy. It was shown that when the functional state of the body changes, the gas composition of molecular substances that are present in the exhaled air is altered indirectly and their levels vary significantly depending on the health of the individual. Our findings suggest that it is possible to study the specific functional properties of the human body to facilitate assessment of the health of an individual to determine whether pathological processes occur in the body at various stages of their severity using diode laser spectroscopy. This paper presents clinical and experimental data on this issue.
关键词： non-invasive diagnostics,diode lasers,gas biomarkers,diode laser spectroscopy
更新于2025-09-23 15:19:57