Tin diselenide (SnSe2) nanosheets as novel 2D layered materials have excellent optical properties with many promising application prospects, such as photoelectric detectors, nonlinear optics, ...infrared photoelectric devices, and ultrafast photonics. Among them, ultrafast photonics has attracted much attention due to its enormous advantages; for instance, extremely fast pulse, strong peak power, and narrow bandwidth. In this work, SnSe2 nanosheets are fabricated by using solvothermal treatment, and the characteristics of SnSe2 are systemically investigated. In addition, the solution of SnSe2 nanosheets is successfully prepared as a fiber‐based saturable absorber by utilizing the evanescent field effect, which can bear a high pump power. 31st‐order subpicosecond harmonic mode locking is generated in an Er‐doped fiber laser, corresponding to the maximum repetition rate of 257.3 MHz and pulse duration of 887 fs. The results show that SnSe2 can be used as an excellent nonlinear photonic device in many fields, such as frequency comb, lasers, photodetectors, etc.
Tin diselenide (SnSe2) nanosheets as novel 2D layered materials have excellent optical properties. SnSe2 nanosheets fabricated by using solvothermal treatment are successfully prepared as fiber‐based saturable absorbers by utilizing the evanescent field effect, which can bear a high pump power. 31st‐order subpicosecond harmonic mode‐locking is generated, corresponding to 257.3 MHz repetition rate.
Fe3O4 nanoparticles (FONPs) are magnetic materials with a small band gap and have well-demonstrated applications in ultrafast photonics, medical science, magnetic detection, and electronics. Very ...recently, FONPs were proposed as an ideal candidate for pulse generation in fiber-based oscillators. However, the pulses obtained to date are on the order of microseconds, which is too long for real application in communication. Here, we report the use of FONPs synthesized by a sol–hydrothermal method and used as a saturable absorber (SA) to achieve nanosecond pulses in an erbium-doped fiber laser (EDFL) for the first time. The proposed fiber laser is demonstrated to have a narrow spectral width of around 0.8 nm and a fixed fundamental repetition rate (RPR) of 4.63 MHz, whose spectra and pulse dynamics are different from the mode-locked lasers reported previously. It is demonstrated that the proposed fiber laser based on a FONP SA operates in the giant-chirp mode-locked regime. The most important result is the demonstration of a pulse duration of 55 ns at an output power of 16.2 mW, which is the shortest pulse based on FONPs for EDFLs reported to date. Our results demonstrate that the FONP dispersion allows for an excellent photonic material for application in ultrafast photonics devices, photoconductive detectors, and optical modulators.
Narrow-bandgap materials possess the intriguing optical-electric properties and unique structures, which can be widely applied in the field of photonics, energy optoelectronic sensing and ...biomedicine, etc. Nowadays, the researches on nonlinear optical properties of narrow-bandgap materials have attracted extensive attention worldwide. In this paper, we review the progress of narrow-bandgap materials from many aspects, such as background, nonlinear optical properties, energy band structure, methods of preparation, and applications. These materials have obvious nonlinear optical characteristics and the interaction with the short pulse laser excitation shows the extremely strong nonlinear absorption characteristics, which leads to the optical limiting or saturable absorption related to Pauli blocking and excited state absorption. Especially, some of these novel narrow-bandgap materials have been utilized for the generation of ultrashort pulse that covers the range from the visible to midinfrared wavelength regions. Hence, the study on these materials paves a new way for the advancement of optoelctronics devices.
Tin diselenide (SnSe2) nanosheets as novel 2D layered materials have excellent optical properties. In article number 1902811, Xiao‐Hui Li and co‐workers characterize SnSe2 nanosheets systemically and ...successfully apply SnSe2 nanosheets in an Er‐doped fiber laser to obtain 31th order subpicosecond harmonic mode‐locking, corresponding to a 257.3‐MHz repetition rate.
Tin diselenide (SnSe
) nanosheets as novel 2D layered materials have excellent optical properties with many promising application prospects, such as photoelectric detectors, nonlinear optics, ...infrared photoelectric devices, and ultrafast photonics. Among them, ultrafast photonics has attracted much attention due to its enormous advantages; for instance, extremely fast pulse, strong peak power, and narrow bandwidth. In this work, SnSe
nanosheets are fabricated by using solvothermal treatment, and the characteristics of SnSe
are systemically investigated. In addition, the solution of SnSe
nanosheets is successfully prepared as a fiber-based saturable absorber by utilizing the evanescent field effect, which can bear a high pump power. 31st-order subpicosecond harmonic mode locking is generated in an Er-doped fiber laser, corresponding to the maximum repetition rate of 257.3 MHz and pulse duration of 887 fs. The results show that SnSe
can be used as an excellent nonlinear photonic device in many fields, such as frequency comb, lasers, photodetectors, etc.
Previous studies revealed that extracellular regulated kinase-1 and -2 （ERK1/2） cascade plays pivotal roles in regulating oocyte meiotic cell cycle progression. However, most knowledge about the in ...vivo function of ERK1/2 in mammalian oocytes was indirectly obtained from analyzing the phenotypes of Mos knockout mice. In this study, we knocked out Erkl and Erk2 in mouse oocytes as early as the primordial follicle stage using the well-characterized Gdp-Cre mouse model, and for the first time directly investigated the in vivo function of ERK1/2 in mouse oocytes. In this novel mouse model, we observed that ERK1/2 activities in oocyte are dispensable for primordial follicle maintenance, activation and follicle growth. Different from the Mos null oocytes, the ERK1/2-deleted oocytes had well-assembled spindles at metaphase I （MI）, extruded polar body-I （PB1） with normal sizes, and did not undergo a full parthenogenetic activation characterized for pronuclear formation. However, the ovulated ERK1/2-deleted oocytes had poorly-assembled metaphase II （MII） spindles, spontaneously released polar body-2 （PB2）, and were arrested at another metaphase called metaphase III （MIII）. In addition, ERK1/2 deletion prevented male pronuclear formation after fertilization, and caused female infertility. In conclusion, these results indicate that ERK1/2 activities are required for not only MII-arrest maintenance, but also efficient pronuclear formation in mouse oocytes.
Dear Editor, Androgen Insensitivity Syndrome （AIS） is an X-linked recessive genetic disorder presenting as male pseudohermaphroditism with gender ambiguity or reversal. According to the reaction to ...androgens, subjects with AIS can exhibit varying degrees of feminization, mainly in two forms.
Fe
O
nanoparticles (FONPs) are magnetic materials with a small band gap and have well-demonstrated applications in ultrafast photonics, medical science, magnetic detection, and electronics. Very ...recently, FONPs were proposed as an ideal candidate for pulse generation in fiber-based oscillators. However, the pulses obtained to date are on the order of microseconds, which is too long for real application in communication. Here, we report the use of FONPs synthesized by a sol-hydrothermal method and used as a saturable absorber (SA) to achieve nanosecond pulses in an erbium-doped fiber laser (EDFL) for the first time. The proposed fiber laser is demonstrated to have a narrow spectral width of around 0.8 nm and a fixed fundamental repetition rate (RPR) of 4.63 MHz, whose spectra and pulse dynamics are different from the mode-locked lasers reported previously. It is demonstrated that the proposed fiber laser based on a FONP SA operates in the giant-chirp mode-locked regime. The most important result is the demonstration of a pulse duration of 55 ns at an output power of 16.2 mW, which is the shortest pulse based on FONPs for EDFLs reported to date. Our results demonstrate that the FONP dispersion allows for an excellent photonic material for application in ultrafast photonics devices, photoconductive detectors, and optical modulators.
Granulocytic sarcoma （GS） is an extramedullary tumor mass consisting of immature myeloid cells. Isolated pancreatic granulocyte sarcoma is extremely rare. We report a very unusual pancreatic ...granulocytic sarcoma in a patient without acute myeloid leukemia. The patient presented with acute epigastric pain because of splenic infarction due to a mass consisting of myeloblasts in the pancreatic tail. The patients underwent splenectomy and distal pancreatectomy. Pathology and immunohistochemistry suggested a GS. Despite local surgery, an isolated tumor recurred 2 mo after operation and the patient died 3 mo after removal of the tumor. Only 7 reported cases of pancreatic GS were identified in the literature and the mass was located in the pancreatic head. This is the first report of GS in the pancreatic tail with splenic infarction.
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