Lawrenceyork0102

Scanning imaging systems are susceptible to image warping in the presence of target motion occurring within the time required to acquire an individual image frame. In this Letter, we introduce the use of a dual raster scanning approach to correct for motion distortion without the need for prior knowledge of the undistorted image. In the dual scanning approach, the target is imaged simultaneously with two imaging beams from the same imaging system. The two imaging beams share a common pupil but have a spatial shift between the beams on the imaging plane. The spatial shift can be used to measure high speed events, because it measures an identical region at two different times within the time required for acquisition of a single frame. In addition, it provides accurate spatial information, since two different regions on the target are imaged simultaneously, providing an undistorted estimate of the spatial relation between regions. These spatial and temporal relations accurately measure target motion. Data from adaptive optics scanning laser ophthalmoscope (AOSLO) imaging of the human retina are used to demonstrate this technique. We apply the technique to correct the shearing of retinal images produced by eye motion. Three control subjects were measured while imaging different retinal layers and retinal locations to qualify the effectiveness of the algorithm. Since the time shift between channels is readily adjustable, this method can be tuned to match different imaging situations. The major requirement is the need to separate the two images; in our case, we used different near infrared spectral regions and dichroic filters.We propose a frequency hopping receiving method that can receive signals with a large frequency hopping range and rapid hopping speed simultaneously. It is based on simultaneous photonic filtering and digitizing, and the reception frequency is tuned by changing the temporal shape of the sampling optical pulse. The proposed receiving method is verified by an experimental verification scheme. In the verification scheme, the optical pulse from a mode-locked laser is shaped to obtain several sub-pulses with different temporal shapes by spectral shaping and frequency-to-time mapping. The reception of the frequency hopping signal is performed by introducing certain delay through a switchable delay line to select different sub-pulses as the optical sampling pulse. The frequency hopping speed and range of the verification scheme are limited mainly by the speed of the optical switches and the bandwidth of electro-optic modulators, respectively. In experiments, with available devices, frequency hopping signals with a switching time of 250 ns and signals whose carrier frequency hops from 13.35 GHz to 39.30 GHz are successfully received.We report a novel monolithically integrated voltage-controlled metal-oxide-semiconductor field effect transistor (MOSFET)-LED device based on a GaN-on-silicon LED epitaxial wafer. An N-channel enhancement mode MOSFET and an InGaN/GaN multiple-quantum-well (MQW) thin-film LED featured with a suspended membrane are in series connection to constitute the monolithically integrated device without external metal interconnection. selleck chemicals A recessed gate structure and AlGaN channel are innovatively adopted to realize an enhancement mode transistor. The fabrication of the MOSFET-LED includes no additional ion implantation or epitaxial growth compared with that of a common MQW LED, which greatly simplifies the device structure and production processes. The measured turn-on voltage of the LED is approximately 4 V, and the threshold voltage of the MOSFET is extrapolated as 5.2 V. The results demonstrate relatively good dimming and switching capacities of the integrated MOSFET-LED. This integration scheme also has potential to achieve a large-scale optoelectronic integrated circuit.We demonstrate multi-cycle terahertz (MC-THz) generation in a 15.5 mm long periodically poled rubidium (Rb)-doped potassium titanyl phosphate (RbPPKTP) crystal with a poling period of 300 µm. By cryogenically cooling the crystal to 77 K, up to 0.72 µJ terahertz energy is obtained at a frequency of 0.5 THz with a 3 GHz bandwidth. A maximum internal optical-to-terahertz conversion efficiency of 0.16% is achieved, which is comparable with results achieved using periodically poled lithium niobate crystal. Neither photorefractive effects nor damage was observed with up to 900mJ/cm2, showing the great potential of RbPPKTP for multi-millijoule-level MC-THz generation.The surface plasmon resonance (SPR) of metal nanostructures is known to affect the optical properties of solid luminescent materials. Ag nanoparticles were first used to obtain a wider color gamut in rare-earth-doped phosphor-in-glass for application as color filters for white light emitting diodes. The existence of Ag nanocrystallites at nanometer scale and the independent integrity of the phosphor luminescence center in the amorphous glass environment were demonstrated. Using UV-Vis spectroscopy, the localized SPR absorption band was observed at 480 nm, and the optical properties of the nanostructures were found to be dependent on the annealing temperature. Hence, an expansion of the color gamut from 79.07% to 93.31% was realized by the coefficient effect of Nd3+ active ions and Ag nanoparticles. These results suggest that Nd3+-ion-co-doped phosphor-in-glass modified by Ag nanoparticles could be potentially applied as a novel optical material with a wide color gamut.We report the achievement of continuous-wave (CW)-pumped second-harmonic generation (SHG) and sum frequency generation (SFG) in a layered indium selenide (InSe)-integrated microfiber. As a result of the strong interaction between the InSe nanosheets and the evanescent field, the second-order nonlinear processes are greatly enhanced in the InSe-integrated microfiber pumped by a few milliwatt CW lasers. The experimental results reveal that the intensities of SHG and SFG are quadratic and linear dependencies with the incident pump power, respectively, which is consistent with theoretical predictions. Additionally, the SHG intensity is strongly polarization-dependent on the nonaxisymmetrical distribution of the InSe nanosheets around the microfiber, providing the possibility of the SHG-polarized manipulation. The proposed device has the potential to be integrable into all-fiber systems for nonlinear applications.