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Use of YAP(Ce) in the development of high spatial resolution radiation imaging detectors
摘要： A scintillator with a high light output is considered to be required for the development of high spatial resolution radiation imaging detectors. In contrast to this scientific consensus, we found that high spatial resolution images can be obtained using a medium light output scintillator comprising cerium-doped yttrium aluminum perovskite, YA1O3 (YAP(Ce)). We evaluated the performance of a radiation imaging detector comprising a 0.5 mm thick YAP(Ce) plate, which was optically coupled to a 25.4 mm (1-inch) square position-sensitive photomultiplier. The Anger principle was used to calculate the radiation positions. The spatial resolution and energy resolution for the imaging detector with 5.5 MeV alpha particles were 0.2 mm full width at half-maximum (FWHM) and 7.4% FWHM, respectively. The spatial resolutions for 60 keV gamma photons and ~32 keV X-rays were ~ 0.6 mm FWHM and ~ 0.8 mm FWHM, respectively. The spatial resolution of the detector when imaging beta particles at a maximum energy of 254 keV was less than 0.6 mm FWHM. We conclude that YAP(Ce) is a promising scintillator for developing high spatial resolution and high energy resolution radiation detectors for imaging alpha particles, beta particles, and gamma photons.
关键词： YAP(Ce),energy resolution,position-sensitive photomultiplier,spatial resolution
更新于2025-09-23 15:21:21
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Crystal growth and spectroscopic investigations of Dy:YAlO3 and Dy,Tm:YAlO3 crystals for a??3a?ˉ??m laser application
摘要： Dy3+:YAP and Dy3+,Tm3+:YAP single crystals have been successfully synthesized by Czochralski (CZ) method aiming for ~3 μm emission. The optical absorption and emission features of both crystals were studied in detail. A narrow and weak absorption band around 800 nm as well as an upconversion emission under the excitation of 802 nm in Dy3+:YAP crystal along with a weak ~3 μm emission were observed, indicating that Dy3+:YAP crystal is not suitable for direct pumping under 800 nm excitation. Tm3+ ion was introduced as a sensitizer for enhancing ~3 μm emission and found that co-doping with Tm3+ greatly improved the absorption capacity around 800 nm. An enhanced ~3 μm emission was observed in Dy3+,Tm3+:YAP crystal under 795 nm excitation. The energy transfer mechanisms between Dy3+ and Tm3+ ions and the energy transfer micro-parameters were discussed. Higher values of microscopic energy transfer constants between Dy3+ and Tm3+ ions were obtained, proving Tm3+ ion act as an effective sensitizer for Dy3+ ion in YAP crystal. Following the obtained optical results, Dy3+,Tm3+:YAP crystal could be a promising medium for 3 μm laser operation under 795 nm laser diode for practical applications.
关键词： optical absorption,energy transfer micro-parameters,3 μm emission,MIR laser,Dy3+,Tm3+:YAP crystal
更新于2025-09-23 15:21:01
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New technology for coagulation of dilated vessels using the combined effects of several modes of generation and wavelengths in one laser pulse for the treatment of pediatric hemangiomas: Open prospective study
摘要： An open, prospective, nonrandomized study of 122 children with infantile hemangiomas aged 1 to 24 months was conducted to evaluate the effectiveness and safety of treatment with multiline laser equipment using the Nd:YAP Q-Sw/KTP emitters with the combined use of two wavelengths of 1079/540 nm. The average age of the children was (6.3 ± 0.3) months, 22 of them were boys (18.0%) and 100 were girls (82.0%). An erythometry and ultrasound examination were performed to determine the depth of the neoplasm, to assess its blood flow, and the presence and diameter of the supply vessels. Studies of these indicators were conducted for patients before and after the treatment. Laser treatment was performed on 109 patients with 119 hemangiomas. A total of 81 superficial hemangiomas underwent a short course of laser therapy (2-5 procedures) and remaining patients with 38 combined hemangiomas received a long course of laser treatment, consisting of 6 to 10 procedures. Restoration of normal color, skin relief, and the absence of scars were noted in post-treatment sample on evaluation. After the course of treatment, erythometry readings corresponded to the values of normal skin and decreased to 110 to 80 cu. Ultrasound examination showed vascular formation and feed vessels were not visualized.
关键词： skin hemangiomas,Nd:YAP,vascular,infantile hemangioma,KTP laser,childhood hemangioma
更新于2025-09-23 15:19:57
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Laser-diode dual-end-pumped electro-optic Q-switched slab Tm:YAP laser
摘要： A high-repetition-rate and double-end pumped electro-optic Q-switched Tm:YAlO3 (Tm:YAP) laser is reported. The Tm:YAP slab crystal cut by c-axis is used as the laser gain medium, and the RbTiOPO4(RTP) crystal is selected as the electro-optic Q-switched crystal. Choosing volume Bragg gratings (VBG) as the input mirror to narrow the output line width. When the pump power is 79.2 W, at a repetition rate of 10 kHz, maximum average-output-power of 21.96 W is achieved, with the pulse width of 20.64 ns and output energy of 2.20 mJ. The output peak power is 107.3 kW and the slope efficiency is 29.2%. The center wavelength is 1937.87 nm and the line width is 0.73 nm. The beam quality in the x direction is 1.48, and in the y direction is 1.50.
关键词： Electro-optic Q-switch,High repetition rate,Tm:YAP laser,RTP
更新于2025-09-23 15:19:57
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The Efficiency of Verteporfin as a Therapeutic Option in Pre-Clinical Models of Melanoma
摘要： Yes Associated Protein 1 (YAP) and Transcriptional coactivator with PDZ-Binding Motif (TAZ) have gained notoriety for their ability to drive tumor initiation and progression in a wide variety of cancers, including melanoma. YAP and TAZ act as drivers of melanoma through its interaction with the TEAD family of transcription factors. Verteporfin is a benzoporphyrin derivative that is used clinically for photodynamic treatment of macular degeneration. Recently it has emerged as a potential inhibitor of YAP/TAZ-TEAD interaction independent of light activation. In this study we determine if verteporfin has clinical potential by testing this compound on human melanoma cell cultures and in a clinically significant mouse model, BrafCA; Tyr-CreERT2; Ptenf/f, which parallels human melanoma in terms of disease progression, genetics, and histopathology. In culture, Verteporfin treatment induces a rapid drop in YAP and TAZ protein levels and cell numbers. In the transgenic model, utilizing drug levels that correspond to previously determined safe doses in human patients and with a dosing regimen calculated in this study, Verteporfin did not inhibit melanoma initiation or progression in comparison to mock treated controls. Taken together, our study suggests that although Verteporfin induces YAP/TAZ degradation in melanoma cell lines, Verteporfin was not effective as a YAP/TAZ-TEAD specific inhibitor of melanoma in our studies that aimed to mimic conditions found in clinic in terms of treatment regimen and disease model.
关键词： TAZ,Verteporfin,hippo pathway,mouse models,melanoma,YAP
更新于2025-09-19 17:15:36
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Stable pulse output of a diode-pumped Tm:YAP laser based on the longitudinal mode beating effect
摘要： We successfully demonstrate the stable pulse output of a diode-end-pumped Tm:YAP laser based on the longitudinal mode beating technique. Without any additional modulation elements in the cavity, the stable pulse output of a Tm:YAP laser at 1937 nm is achieved. At an absorbed pump power of 6 W, the average output power of 1.14 W is obtained with a slope efficiency of 23%, and the pulse duration is 5.3 ns with a pulse repetition frequency of 89 MHz. To the best of our knowledge, this is the first 2 μm self-pulsing solid-state laser based on the longitudinal mode beating effect.
关键词： self-pulsing laser,diode pumped lasers,all-solid-state laser,Tm:YAP
更新于2025-09-19 17:13:59
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In-band pumped, high-efficiency LGS electro-optically Q-switched 2118??nm Ho:YAP laser with low driving voltage
摘要： An in-band end-pumped LGS electro-optically (EO) Q-switched Ho:YAP laser has been investigated and demonstrated. The LGS crystal based on EO modulator was designed to operate in pulse-on mode with a 1/4 wave voltage of 2400 V, which was the lowest driving voltage at 2 μm wavelength for LGS crystal as far as we know. Under continuous-wave (CW) regime, a maximum average output power of 6.5 W was obtained from the Ho:YAP laser with a slope efficiency of 50.6% when an incident pump power was 16 W. When running in EO Q-switching regime, a maximum output power of 4 W was obtained with a single pulse energy of 1 mJ and a pulse width of 33 ns at a repetition rate of 4 kHz. At the repetition rate of 2 kHz, the maximum single pulse energy of 1.5 mJ and the shortest pulse width of 23 ns were achieved, corresponding to a pulse peak power of as high as 65 kW.
关键词： EO Q-switched,LGS,Ho:YAP
更新于2025-09-19 17:13:59
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Sb <sub/>2</sub> Te <sub/>3</sub> as the saturable absorber for the ～2.0 μm passively <i>Q</i> -switched solid state pulsed laser
摘要： We demonstrated a passively Q-switched Tm:YAP solid state pulsed laser based on an Sb2Te3 saturable absorber. This saturable absorber was prepared by a facile hydrothermal method. The maximum pulse energy was up to 5.366 mJ at the absorbed pump power of 6.6 W. The corresponding pulse width, output power and repetition rate were 533 ns, 542 mW and 101 kHz, respectively. The results indicated that the hydrothermally synthesized Sb2Te3 nanosheet was a promising saturable absorber for near-infrared pulsed lasers.
关键词： passively Q-switched,solid state pulsed laser,Sb2Te3,saturable absorber,Tm:YAP
更新于2025-09-16 10:30:52
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Nd:YAP laser in the treatment of dentinal hypersensitivity: An ex vivo study.
摘要： Purpose: The aims of this ex vivo study were to evaluate the effectiveness of the Nd:YAP laser in the treatment of dentin hypersensitivity, to compare the temperature rise during laser irradiation at three different dentine thicknesses, and to analyse the composition of the dentine-lased surface. Methods: A total of 33 teeth were used in this study. For scanning electron microscopy (SEM) observation, 24 teeth were transversely sectioned and divided into 4 groups: group A was irrigated with EDTA; group B was irradiated by Nd:YAP laser with 180 mJ energy/per pulse, 0.9 W average power, and 5 Hz frequency (power density [PD] = 229 W/cm2); group C was irradiated by Nd:YAP laser with 280 mJ energy/pulse, 1.4 W average power, and 5 Hz frequency (PD = 356 W/cm2); and group D was irradiated by Nd:YAP with 360 mJ energy/pulse, 1.8 W average power, and 5 Hz frequency (PD = 458W/cm2). Energy-dispersive spectroscopy (EDS) analysis was performed on the same teeth evaluated for SEM observations. For temperature increase evaluation performed with thermocouples, 9 teeth were transversely sectioned at 3 different thicknesses (3 for each group) of 1, 2, and 3 mm. Results: Statistical analysis showed significant changes in the diameter of the dentinal tubule orifices among all groups; EDS did not show modification of the Ca/P ratio. Temperature increase under irradiation exceeded 5.5°C only in the group D samples. Conclusions: This ex vivo study, based on temperature recording, SEM observation, and EDS analysis, demonstrated that Nd:YAP laser at a PD of 356 W/cm2, corresponding to an average power of 1.4 W, defines the best treatment for dentine hypersensitivity in terms of compromise between efficacy of the treatment and safety of the pulp.
关键词： dentinal hypersensitivity,energy-dispersive spectroscopy,thermal evaluation.,Nd:YAP laser,scanning electron microscopy
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Tunable Narrowband Tm:YAP Laser using a Transversally Chirped Volume Bragg Grating
摘要： Tunable long wave infrared (LWIR) coherent sources emitting between 8 and 12 μm can be used for versatile remote gas sensing. In ref [1] we implemented a parametric oscillator in which wavelength tunability was achieved by temperature tuning of the crystal indices of refraction. It is well known that a similar wavelength range can be addressed by tuning the pump wavelength rather than the crystal temperature [2]. In addition, pump tuning can be significantly faster than temperature tuning. In this context we also need a narrow band spectrum to control the spectral output of the optical parametric oscillator, which is based on Vernier spectral filtering in doubly-resonant cavities. Seger and his team exhibited single longitudinal mode operation in a microlaser tuned with transversally chirped volume Bragg grating (TC-VBG) near 1 μm [3]. We show how this concept can be applied to a different laser emitting at 2 μm.
关键词： Tunable laser,LWIR,Tm:YAP,Narrowband,Volume Bragg Grating
更新于2025-09-12 10:27:22