- 标题
- 摘要
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- 实验方案
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A simple extended-cavity diode laser using a precision mirror mount
摘要： We have developed an extended-cavity diode laser (ECDL) with a simple design by using a commercial precision mirror mount with minor modifications. Our design allows tuning of the external cavity configuration by tweaking the volume holographic grating without troublesome changes in the beam path of the laser output. The mode-hop-free tuning range of the presented ECDL is about 8 GHz with a linewidth of 475 kHz.
关键词： volume holographic grating,mode-hop-free tuning range,linewidth,extended-cavity diode laser,precision mirror mount
更新于2025-09-23 15:21:01
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Electromagnetically induced grating with second field quantization in spherical semiconductor quantum dots
摘要： A new approach for diffracting the weak probe beam into higher-order directions is proposed via electromagnetically induced grating in second field quantization formalism, offering a new way for implementations of quantum information with semiconductor quantum dots. The formalism of second field quantization allows describing atoms and photons as a many-body system. An induced diffraction grating is formed based on the electromagnetic induced transparency when a standing-wave coupling field is applied to a spherical quantum dot as a three-level system. Due to phase modulation, the zeroth-order light intensity becomes weak, and the first-order diffraction is improved affectedly. On the contrary, the probe beam is barely diffracted via absorption modulation. The simulation results verify that photon numbers of probe and control fields, as well as other parameters in the QD, can lead to the diffraction efficiency of phase grating to be improved. Phase diffraction grating accompanied with a high transmissivity is demonstrated, and the first-order diffraction efficiency reaches 30%. Also, the impact of QD dimensions on its optical response is investigated. This model may find potential applications in designing the semiconductor quantum dot-based photonic devices in optical communications and quantum information networks.
关键词： Electromagnetically induced grating (EIG),Semiconductor quantum dot (SQD),Second field quantization
更新于2025-09-23 15:21:01
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Modal characteristics of refractive index engineered hybrid plasmonic waveguide
摘要： In this work, we proposed a novel design of a refractive index engineered subwavelength grating silicon-based hybrid plasmonic waveguide via the finite element method. The intensity integral (Γ) in the upper cladding can be controlled by varying the thickness (HSi) of the top silicon layer. The highest evanescent field ratio of 0.85 is obtained at HSi=200 nm which allows the hybrid mode to confine in the low index medium and a large evanescent field resides in the upper cladding. The sensitivity of the waveguide is calculated by monitoring the change in the effective refractive index to the ambient refractive index. The maximum mode sensitivity of 0.7 is obtained. The spectral performance of the subwavelength grating (SWG) hybrid plasmonic waveguide (HPWG) based ring resonator design is studied which exhibits a sensitivity as high as 1000 nm/RIU which is higher than the previously reported values. We believe that the proposed waveguide scheme is an ideal candidate to produce highly sensitive lab-on-chip sensors.
关键词： microring resonator,refractive index sensor,Subwavelength grating hybrid plasmonic waveguide,Evanescent field ratio
更新于2025-09-23 15:21:01
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - A Fiber Bragg Grating-based Wind Erosion Monitoring System
摘要： This paper proposes a wind erosion monitoring system includes a shunt-hedging and cyclone-separation sand sampler built by Fluent and a weighting sensor based on FBG. According to the simulation and experiment, this system had anti strong wind interference performance and time, passively, in real continuously, and in a long distance. it could measure
关键词： wind erosion,weighting sensor,sand sampler,fiber Bragg grating
更新于2025-09-23 15:21:01
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High-peak-power and narrow-linewidth Q-switched Ho:YAG laser in-band pumped at 1931 nm
摘要： We describe a high-peak-power, narrow-linewidth Q-switched Ho:YAG laser at 2097 nm wing-pumped by a high power and high brightness Tm:fiber source at 1931.5 nm. The laser was wavelength locked and spectrum narrowed utilizing a volume Bragg grating as the input coupler, resulting a linewidth (FWHM) of less than 0.1 nm. At 22.7 W of incident pump power, stable pulses of 5.5 mJ pulse energy and 17.5 ns of pulse duration have been generated at repetition frequency of 1 kHz, corresponding to peak power of 314.3 kW.
关键词： narrow-linewidth,Q-switched Ho:YAG laser,volume Bragg grating,1931.5 nm,high-peak-power
更新于2025-09-23 15:21:01
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Slit beam shaping technique for femtosecond laser inscription of enhanced plane-by-plane FBGs
摘要： In this work, the development of plane-by-plane (Pl-b-Pl) fiber Bragg gratings (FBGs) by using a single pulse is reported. A slit oriented along the longitudinal axis of the fiber is employed for this. The purpose is to shape the beam so that the focal volume is spatially wider in the transverse direction of the fiber. In this way, it is possible to make 2-D modifications of the refractive index whose width and height depends on the slit width and the pulse energy, respectively. Through an analytical mathematical modelling, the relationship between the diameter of the Gaussian laser beam (Dx) and the slit width (s = Dy) is determined in order to obtain a circular cross-section. In the experimental results carried out, it can be observed that Dx/Dy=3 ratio cause positive and uniform refractive index changes, compared to the negative and inhomogeneous refractive index changes corresponding to point-by-point (PbP) FBGs. Likewise, Pl-b-Pl FBGs, presenting a broader modification of the core cross-section, show significantly lower losses in transmission (0.3 dB), as well as better reflectivity and FWHM. It is observed that these three parameters (losses, reflectivity and FWHM) have a monotonous tendency according to the slit width. Polarization-dependence is also evaluated.
关键词： Optical Fiber Sensor,Slit beam technique,Femtosecond laser,Plane-by-Plane,Fiber Bragg grating
更新于2025-09-23 15:21:01
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Chirped polarization volume grating for wide FOV and higha??efficiency waveguidea??based AR displays
摘要： We demonstrate a reflective chirped polarization volume grating as a strong contender for wide field-of-view augmented reality display systems. By introducing gradient pitch along the beam propagation direction, the angular bandwidth extends dramatically from 18(cid:1) to 54(cid:1) while keeping over 80% average efficiency and 95% peak efficiency.
关键词： liquid crystals,augmented reality,polarization volume grating,gradient pitch structure
更新于2025-09-23 15:21:01
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Investigation of laser damage of grating waveguide structures submitted to sub-picosecond pulses
摘要： Grating waveguide structures (GWS) are reflective diffractive optical elements that operate based on the combination of sub-wavelength gratings (periodic microstructures) integrated with planar waveguides. They can be used for high-power laser applications for pulse compression, spectral stabilization, wavelength multiplexing, as well as polarization shaping. In this work, we investigate the laser-damage resistance of GWS based on Ta2O5/SiO2 multilayers at pulse durations of 500 fs and wavelength of 1030 nm. We particularly study the influence of the material of the multilayer sequence, the designed grating structure, and the operational conditions (angle of incidence and polarization of the laser beam) on the laser-damage resistance of the GWS. Comparison of measurements to simulation of the electric-field distribution in the structure reveals a good correlation between laser-induced damage threshold (LIDT) values and electric-field enhancement in the structure. Based on this work, an optimized design has been defined to increase the LIDT of the GWS. An improvement of the LIDT of a factor 2 has been obtained.
关键词： Ta2O5/SiO2 multilayers,Grating waveguide structures,Electric-field distribution,Sub-picosecond pulses,Laser-damage resistance
更新于2025-09-23 15:21:01
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Impact of Transient Population Grating on the Superradiant Phase Transition in Semiconductor Laser Structures
摘要： We study theoretically and experimentally superradiant dynamics in multiple-section GaAs/AlGaAs laser structures. We develop a model based on the one-dimensional Maxwell curl equations without making use of the slowly-varying envelope approximation and demonstrate that strong transient periodic modulation of both e – h density and refractive index drastically affect the dynamics of emission generation in semiconductor media. We show that the coherent λ/2 transient population and the relative permittivity gratings facilitate e – h self-ordering and the onset of the superradiant phase transition in the e – h system.
关键词： self-organization,superradiance,phase transition,population grating
更新于2025-09-23 15:21:01
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High-Performance Enhancement of a GaAs Photodetector Using a Plasmonic Grating
摘要： In this study, we present and establish a gold surface plasmon polariton (SPP) GaAs photodetector that achieves high internal quantum efficiency (IQE). At a wavelength of 600 nm, the IQE with the SPP was 85%, while the IQE without the SPP was 42%, an enhancement of 43%. Also, at a wavelength of 675 nm, the IQE with SPP was 82%, whereas the IQE without SPP was 45%, which constitutes an increase of 37%. Such excellent performance is ascribed to the subwavelength scope of the optical power in the photoconductive-based gold SPP GaAs that provides high IQE. Moreover, the recombination of the SPP in the photodetector provides greater photocurrent and responsivity.
关键词： Surface plasmon polaritons,GaAs photodetector,Plasmonic photodetectors,Light trapping,Plasmonic grating
更新于2025-09-23 15:21:01