Huntgrossman2365

Graphene has taken impressive roles in light manipulation and optical engineering. Iressa The most attractive advantage of graphene is its tunable conductivity that could be dynamically modulated by various means. In this paper, we show that the spin Hall shift of light is dynamically tunable via changing the Fermi level of the graphene-wrapped spheres. Such tunability is prominent when different modes interfere with each other, such as at the interference of electric and magnetic dipolar modes or at the interference of electric dipolar and electric quadrupole modes. The circular polarization degree in the near field clearly demonstrates the strength of spin-orbit interaction, which is associated with spin Hall shift of light in the far-field. In addition, the spin Hall effect is shown in far-field detection plane and should be observed in experiment. Our results provide insights into how the spin Hall effect could be tuned and add new perspective in designing optical super-resolution imaging techniques.The pulse dynamics of a self-starting Yb-doped fiber Mamyshev oscillator without external seed pulses or additional starting arms is demonstrated experimentally. Multiple dynamic patterns of pulses, including single pulses, bound-state pulses, and harmonic mode-locking pulses, are observed at different pump powers and filter spectral separations. The generation and evolution of bound states have also been simulated by establishing the corresponding theoretical model. This is the first systematic theoretical and experimental study of the formation and evolution of bound states in Yb-doped Mamyshev oscillators. The numerical results are in excellent agreement with experiment results, providing validation of both the measurements and the numerical model.We report an enhanced photon count rate in a digitally implemented time-correlated single-photon counting (TCSPC) system by utilizing a hybrid photodetector (HPD). In our digital TCSPC scheme, the photoelectronic responses from a single photon-sensitive photodetector are digitally analyzed through a high-speed analog-to-digital convertor (ADC). By virtue of the HPD which provides nearly a constant signal gain, the single-photon pulses can be effectively distinguished from pulses of simultaneously detected multiple photons by the pulse heights. Consequently, our digital TCSPC system can selectively collect single-photon signals even in the presence of intense multi-photon detections with its temporal accuracy not to be compromised. In our experiment of fluorescence lifetime measurement, the maximum count rate of single photons nearly reached the theoretical limit given by the Poisson statistics. This demonstrated that the digital TCSPC combined with the HPD provides an ultimate solution for the TCSPC implementation for high photon count rates.This research experimentally demonstrates a switchable, single-wavelength, thulium-doped fiber laser based on the cascading of a multimode-single-mode-multimode (MSM) fiber filter and a two-mode fiber (TMF) filter. When the MSM fiber filter suffers from bending, the blue-shift of the output spectrum can be obtained. A switchable lasing wavelength output is realized by bending the MSM fiber filter to cover different channels of the TMF filter. The output wavelength can be switched from 1982.54 to 1938.81 nm with an optical signal-to-noise ratio of higher than 40 dB. The wavelength interval of the switchable output is an integral multiple of the wavelength interval of the TMF filter. The stability of the output wavelength was tested within 60 min, and the wavelength shift and output power fluctuation were found to be less than 0.01 nm and 0.31 dB, respectively, which demonstrates a stable output performance.As an essential element for quantum information processing and quantum communication, efficient quantum memory based on solid-state platforms is imperative for practical applications but remains a challenge. Here we propose a scheme to realize a highly efficient and controllable storage and routing of single photons based on quantum dots (QDs) with a Rashba spin-orbit coupling (SOC). We show that the SOC in the QDs can provide a flexible built-up of electromagnetically induced transparency (EIT) for single-photon propagation, and storage, retrieval, as well as routing of single-photon wavepackets can also be implemented through the EIT. Moreover, we demonstrate that the propagation loss of the single-photon wavepackets in the QDs may be largely suppressed by means of a weak microwave field, by which the storage and routing of the single photons can be made to have high efficiency and fidelity. Our research opens a route for designs of advanced solid-state devices promising for applications in photonic quantum-information processing and transmission based on the QDs with SOC.We propose a preliminary lensless inference camera (LLI camera) specialized for object recognition. The LLI camera performs computationally efficient data preprocessing on the optically encoded pattern through the mask, rather than performing computationally expensive image reconstruction before inference. Therefore, the LLI camera avoids expensive computation and achieves real-time inference. This work proposes a new data preprocessing approach, named local binary patterns map generation, dedicated for optically encoded pattern through the mask. This preprocessing approach greatly improves encoded pattern's robustness to local disturbances in the scene, making the LLI camera's practical application possible. The performance of the LLI camera is analyzed through optical experiments on handwritten digit recognition and gender estimation under conditions with changing illumination and a moving target.A diode laser module emitting 1.4 kW optical in-pulse power near 780 nm optimized for high (≥ 10%) duty-cycle operation in a micro-channel free design is presented. With full collimation, a beam quality with a nearly symmetric M2 of 205 × 295 (vertical × horizontal direction) for a wide range of pulse widths is found.Large-scale passive resonant gyroscopes (PRGs) have been utilized in the measurement of Earth rotation. We report on a scheme of phase-sensitive heterodyne detection in large-scale PRGs. By injecting three separated beams into different longitudinal modes of the ring cavity and self-demodulating the detected signals, the backscattering disturbance and the cavity length fluctuation effect both can be isolated. With the implementation of this new scheme, we can obtain the Earth rotation signal with a Sagnac frequency that is twice of that of the traditional scheme, which enhance the equivalent scale factor of the laser gyroscopes. On the other hand, the quantum noise limit of the instrument can also be further suppressed due to the improvement of the signal-to-noise ratio. With this new scheme, the theoretical rotational sensitivity of a 3 m × 3 m large scale PRG can be as low as 10-12 rad/s/Hz. With this rotational sensitivity, the measurement of the length of day or the test of the general relativity can be realized.