Mode-locked fibre lasers (MLFLs) are fundamental building blocks of many photonic systems used in industrial, scientific and biomedical applications. To date, 1-2 μm MLFLs have been well developed; ...however, passively mode-locked fibre lasers in the visible region (380-760 nm) have never been reported. Here, we address this challenge by demonstrating an all-fibre visible-wavelength passively mode-locked picosecond laser at 635 nm. The 635 nm mode-locked laser with an all-fibre figure-eight cavity uses a Pr/Yb codoped ZBLAN fibre as the visible gain medium and a nonlinear amplifying loop mirror as the mode-locking element. First, we theoretically predict and analyse the formation and evolution of 635 nm mode-locked pulses in the dissipative soliton resonance (DSR) regime by solving the Ginzburg-Landau equation. Then, we experimentally demonstrate the stable generation of 635 nm DSR mode-locked pulses with a pulse duration as short as ~96 ps, a radio-frequency signal-to-noise ratio of 67 dB and a narrow spectral bandwidth of <0.1 nm. The experimental results are in excellent agreement with our numerical simulations. In addition, we also observe 635 nm noise-like pulse operation with a wide (>1 nm) and modulated optical spectrum. This work represents an important step towards miniaturized ultrafast fibre lasers in the visible spectral region.
Immunogenic cell death (ICD) stimulates adaptive immunity and holds significant promise in cancer therapy. Nevertheless, the influence of ICD-associated long non-coding RNAs (lncRNAs) on the ...prognosis of patients with lung squamous cell carcinoma (LUSC) remains unexplored.
We employed data from the The Cancer Genome Atlas (TCGA)database to identify ICD-related lncRNAs associated with the prognosis of LUSC using univariate Cox regression analysis. Subsequently, we utilized the LOSS regression model to construct a predictive risk model for assessing the prognosis of LUSC patients based on ICD-related lncRNAs. Our study randomly allocated187 TCGA patients into a training group and 184 patients for testing the predictive model. Furthermore, we conducted quantitative polymerase chain reaction (qPCR) analysis on 43 tumor tissues from LUSC patients to evaluate lncRNA expression levelsPearson correlation analysis was utilized to analyze the correlation of risk scores with positron emission tomography/computed tomography (PET/CT) parameters among LUSC patients.
The findings from the univariate Cox regression revealed 16 ICD-associated lncRNAs linked to LUSC prognosis, with 12 of these lncRNAs integrated into our risk model utilizing the LOSS regression. Survival analysis indicated a markedly higher overall survival time among patients in the low-risk group compared to those in the high-risk group. The area under the Receiver operating characteristic (ROC) curve to differentiate high-risk and low-risk patients was 0.688. Additionally, the overall survival rate was superior in the low-risk group compared to the high-risk group. Correlation analysis demonstrated a positive association between the risk score calculated based on the ICD-lncRNA risk model and the maximum standard uptake value (SUVmax) (r = 0.427, P = 0.0043) as well as metabolic volume (MTV)of PET-CT (r = 0.360, P = 0.0177) in 43 LUSC patients.
We have successfully developed a risk model founded on ICD-related lncRNAs that proves effective in predicting the overall survival of LUSC patients.
The recent renaissance in pulsed lasers operating in the visible spectral region has been driven by their significant applications in a wide range of fields such as display technology, medicine, ...microscopy, material processing, and scientific research. Low-dimensional nanomaterials as saturable absorbers are exploited to create strong nonlinear saturable absorption for pulse generation at visible wavelengths due to their absorption peaks located in visible spectral region. Here we provide a detailed overview of visible-wavelength pulsed lasers based on low-dimensional nanomaterials, covering the optical properties and various integration strategies of these nanomaterials saturable absorbers, and their performance from solid-state as well as fiber pulsed lasers in the visible spectral range. This emerging application domain will undoubtedly lead to the rapid development of visible pulsed lasers.
In this paper, we report a 488 nm blue picosecond pulse generation by frequency doubling of a homemade 977 nm watt-level picosecond all polarization maintaining mode-locked fiber laser. Based on a ...SESAM passively mode-locked Yb-doped fiber linear cavity configuration, the 977 nm picosecond seed laser shows a 977.84 nm central wavelength, 0.13 nm spectral width, 12.94 ps pulse duration, 76.09 MHz repetition rate, and 5.12 mW average power, respectively. The average power is further scaled up to 2.06 W by adopting an all-fiber MOPA structure, and the pulse duration and spectral width are slightly broadened to 16.84 ps and 0.24 nm, respectively. Furthermore, a 147.40 mW blue picosecond pulsed laser with a 488.92 nm central wavelength and 0.17 nm linewidth is successfully achieved by frequency doubling in a MgO 2 :PPLN crystal. Such compact, high-power, and narrow-linewidth picosecond blue laser is a promising candidate for high-resolution imaging, underwater detection and material processing, etc.
•The high-power 635 nm red laser in the compact all-fiber format based on visible dielectric-coated fiber mirror technology and the down-conversion gain.•The highest continuous-wave output power of ...fiber laser operating in the visible wavelength region to date.•Comparative experiments were performed on the reflectivity of the output mirror and the length of the active fiber to optimize the results.
We propose and experimentally demonstrate a compact high-power all-fiber Pr3+-doped red laser at 635 nm using highly-resistant dielectric-coated fiber mirror. The fiber laser consists of a 443 nm pump laser diode (LD), a double-clad Pr3+-doped fluoride fiber and a 443/635 nm dichroic fiber mirror. The 635 nm laser is directly generated by down-conversion gain of the Pr3+-doped fiber pumped by the 443 nm LD. The homemade dichroic fiber mirror is specifically designed for anti-reflection at 443 nm pump wavelength and high-reflection at 635 nm laser wavelength, and shows a high damaged density of >15 MW/cm2, which is very favorable to high-power visible laser operation. The red all-fiber laser directly generates a highest average power of ∼5 W at 635 nm which is more than twofold higher than previously reported, and the slope efficiency is as high as 25.7%. Different from the traditional visible laser by frequency doubling, this work offers a promising way for miniaturized, high-power fiber lasers in visible wavelength region.
We report, to the best of our knowledge, the first visible-wavelength all-fiber passively mode-locked vortex laser by a figure-9 cavity in combination with <inline-formula><tex-math ...notation="LaTeX">\sim</tex-math></inline-formula>635 nm mode selective coupler, which can deliver picosecond optical vortex pulses with topological charges of OAM<inline-formula><tex-math notation="LaTeX">_{\pm 1}</tex-math></inline-formula>. The mode-locked vortex laser emits stable rectangular pulses with pulse duration tunable range from 85 to 510 ps and a 0.16-nm narrow linewidth at 634.36 nm. The maximum output power of the vortex laser reaches 1.3 mW with a high purity <inline-formula><tex-math notation="LaTeX">\sim 97.2\%</tex-math></inline-formula>. This work demonstrated the generation of picosecond pulsed vortex in visible passively mode-locked fiber laser, showing their potential for applications in particle trapping, optical tweezers, and high-resolution microscopy.
As deep-red semiconductor lasers are still in development, high-power deep-red lasers have traditionally relied on excimer or dye lasers, or nonlinear frequency conversion of near-infrared lasers, ...precluding efficient, compact, and affordable laser systems. Herein, the first compact watt-level all-fiber CW Pr<inline-formula><tex-math notation="LaTeX">^{3+}</tex-math></inline-formula>-doped laser operating in the deep-red waveband was developed to navigate the challenge. The all-fiber laser consists of a double-clad Pr<inline-formula><tex-math notation="LaTeX">^{3+}</tex-math></inline-formula>-doped fluoride fiber, two homemade visible fiber dichroic mirrors with a damaged intensity of <inline-formula><tex-math notation="LaTeX">\gt </tex-math></inline-formula>15 MW/cm<inline-formula><tex-math notation="LaTeX">^{2}</tex-math></inline-formula>, and a 443-nm high-power pump source with a multimode fiber-pigtail output. We exhaustively investigated the influences of the gain fiber length and the reflectivity of output mirrors on the deep-red laser performance by experiments and simulations. A maximum average power of 4.1 W at 717 nm was directly obtained under a pump power of 20.2 W, which is more than five times higher than previously reported. The laser slope efficiency is as high as 22.2%, and its power fluctuation is less than 0.93%. Such a compact high-power all-fiber deep-red laser holds promise for applications in biophotonics, biomedicine, and UV laser generation.
We report, to the best of our knowledge, the first all-fiber passively mode-locked laser around 800 nm wavelength. The laser with a figure-9 cavity configuration consists of a homemade 1146 nm Raman ...fiber laser as pump source, a 2.1 m-length Tm<inline-formula> <tex-math notation="LaTeX">^{3+} </tex-math></inline-formula>-doped ZBLAN fiber, a 0.8/<inline-formula> <tex-math notation="LaTeX">1.15~\mu \text{m} </tex-math></inline-formula> fiber end-facet dichroic mirror, and a nonlinear optical loop mirror (NOLM). The NOLM is not only employed as the output cavity mirror, and also initiates passive mode-locking. The mode-locked center wavelength is 816 nm with a 3-dB bandwidth of ~0.35 nm. The mode-locked rectangular pulse in the noise-like regime has a pulse duration of 486.7 ps with the 7.826 MHz repetition rate. The maximum average power is as high as 488.5 mW and the pulse energy is 62.4 nJ. This work represents an important step towards ~800 nm short-wavelength ultrafast fiber lasers and may has potential applications in biological imaging and medical treatment.
Terahertz (THz) wave generation based on ultrafast laser are one of the most predominant and popular technologies. In particular, for THz generation by photoconductor antenna and optical ...rectification, higher optical to THz conversion efficiency usually requires ultrafast laser excitation into semiconductor or nonlinear crystal, therefore it is of great desire to develop ultrafast laser with high performance. CW Yb-doped lasers at 980 nm have been applied to generate THz wave range from 0.5 to 6 THz by DFG technique. To meet the demand of some THz wave generation (e.g. BNA crystal, gold nanoplasma), 980 nm ultrafast fiber laser are ideal pump sources and in desire to be developed. Here we demonstrate a 978 nm robust all-polarization-maintaining (PM) picosecond fiber laser mode- locked by phase-biased nonlinear amplifying loop mirror (PB- NALM). By introducing a nonreciprocal -<inline-formula><tex-math notation="LaTeX">\pi</tex-math></inline-formula>/2 phase shifter into the fiber loop, a self-starting stable mode-locking is obtained with the center wavelength of 978.14 nm and a 3-dB bandwidth of 0.43 nm. The pulse duration is 8.1 ps corresponding to the time bandwidth product (TBP) of 1.09. The maximum average output power is 14.5 mW with a repetition rate of 45.438 MHz. After a master oscillator power amplification system, the 978 nm average output power reaches 2.12 W, which is then injected into a PPLN crystal for second harmonic generation and 52 mW 489 nm ultrashort lasers is obtained. This is, to the best of our knowledge, the first report of PB-NALM-based mode-locked fiber laser at 978 nm. The 978 nm ultrafast fiber laser and SHG to 489 nm have great potential in terahertz emission by shorter NIR and blue light.
Spatiotemporal mode‐locking (STML) in fiber lasers are of interest in applications such as optical communications, nonlinear imaging, and precision machining. To date, STML fiber lasers in the ...near‐infrared region have been well demonstrated, yet operation at visible wavelengths is still challenging. Here, a STML picosecond fiber laser at 635 nm with the implementation of Pr3+$^{3+}$/Yb3+$^{3+}$ co‐doped few‐mode fiber and nonlinear polarization rotation technology is reported. By solving the modified generalized multimode nonlinear Schrödinger equation, the 635 nm STML formation is theoretically predicted and analyzed. The stable 635 nm STML with a 9 ps pulse duration, which is two orders of magnitude narrower than previously reported, is realized experimentally. Moreover, spatiotemporal profiles are illustrated by investigating the locking of transverse and longitudinal modes simultaneously. By further establishing visible ultrafast fiber amplifier, the 635 nm average power is boosted up to 440 mW, corresponding to a maximum pulse energy and peak power of 4 nJ and 280 W, respectively. The experimental results are in good agreement with the numerical simulations. This work helps to understand nonlinear dynamics in STML fiber laser and directly generate large‐energy ultrashort pulses in visible region.
To date, spatiotemporal mode‐locking (STML) of fiber lasers in the near‐infrared region have been well demonstrated, yet operation at visible wavelengths is still challenging. Here, a 635 nm STML fiber laser is reported with a 9 ps pulse duration, and the average power is amplified up to 440 mW (corresponding to 4 nJ pulse energy).
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