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Rayleigh criterion, based on wave optics, is imposed as a limit on the resolution of optical devices, but resolution beyond Rayleigh criterion has been reported. The current optical analysis and optical design is based on geometrical optics or wave optics. Hence we think that the resolution beyond Rayleigh criterion is owing to the limitations of the theoretical foundations. Also given to the need...
Abstract-Based on high-power laser diodes series beam combine and fiber-coupled technology, a practical method of coupling between laser diodes and multimode fiber with concave mirror is presented. First, the output beam from a laser diode is collimated by a section of multi-mode fiber; beams are rearranged by the plane mirror and concave mirrors in space and coupled into the optical fiber by a non-spherical...
The structure of a collinear surface acoustic wave (CSAW) acousto-electro-optic (AEO) modulator is presented. SAW AEO Coupled wave equations are given. By solving these equations, conversion efficiency formula of CSAW AEO modulator is obtained. Conversion efficiency as the function of acoustic power density is presented in x-cut y-propagating lithium niobate substrate with a titanium in-diffused surface...
We experimentally demonstrate that the mode-locked femtosecond pulse laser is a promising tool for long distance metrology. Distances up to 50m in air were measured and compared to a conventional counting laser interferometer. The measurements were in agreement within 1 μm.
The influence of focal length on optical limiting power characteristics based on stimulated Brillouin scattering in CCl4 medium is investigated numerically and experimentally. The simulation results show that, the characteristics of limiting power and pulse shape are controlled mainly by focal length when other parameters are fixed. When focal length is short, for example 5 cm, the characteristic...
Stereoscopic image acquisition and stereoscopic three dimensional (3D) displays are interdependent and inseparable. The scenes reproduced in 3D displays are captured by stereoscopic image acquisition, and the contents obtained by stereoscopic image acquisition are finally shown in 3D displays. The paper reviews various layout structures of the stereo cameras and their advantages and advantages. The...
A novel all-optical multiplexing scheme based on dispersion matching technique is proposed and experimentally demonstrated. The multiplexing parts are constructed by employing only standard single mode fibers and dispersion compensation fibers, which are simple and stable. The eye diagrams and bit error rate performance of such a multiplexing transmission system are also shown in this letter.
A three-terminal optical sensor by using an aluminum-doped zinc oxide (AZO)-gated Al0.2Ga0.8As/In0.2Ga0.8As high electron mobility transistor (AZO-HEMT) on a GaAs substrate is demonstrated in this report. Optical responses under illumination of different wavelengths are investigated, as compared to a conventional Au-gated HEMT device. Experimental results demonstrate that the present design is promising...
An imaging system with three-waveband sharing one lens and an area CCD was developed. By rotating different filters into the beam path, the required waveband was selected. The optical system which can image in ultraviolet, visible and near infrared region was designed and the signal collecting system was integrated. The optical design and system integration have some advantages such as low cost, small...
The optical local oscillator power which makes the maximized signal-to-noise ratio is analyzed. Aiming at photovoltaic detector, the optimum optical local oscillator power is researched, and the theoretic value of optimum optical local oscillator power is acquired, and takes some experimental research basing on the theory.
Bioluminescence imaging technique was regarded as a promising tool for tumor resection guidance. In this paper, we present an equivalence approximation method for bio-luminescence imaging to reconstruct the location of internal bioluminescent source. Using this method, analytic solution for 3D position of light source can be achieved without parameters of the tissue. The performance is verified by...
Low-power laser irradiation (LPLI), a non-damage physical therapy, which has been used clinically for decades of years, was shown to promote cell proliferation and prevent apoptosis. Apoptosis is a contributing pathophysiological mechanism of Alzheimer's disease (AD). However, whether LPLI could prevent apoptosis in AD model is not clear. In this study, we demonstrated for the first time that LPLI...
High repetition rate laser pulses amplified was of great significance. It was reported that the 320MHz mode-locking pulses were amplified by using a double-cladding ytterbium-doped fiber. The maximum output power is 1.2W and the gain is 16dB when the power of signal is 31mW and the launched pump power is 10W. The experiment demonstrated the self-oscillation was happen near the 1080nm when the fiber...
Strain/vibration detection developed by optical Fabry-Perot sensor is applied in several situations involving building health monitoring, displacement detection, underwater hydrophone and acoustic wave detection. The fiber Fabry-Perot interferometer(FFPI) serves as an excellent tool for detecting acoustic waves because its high sensitivity and high frequency response, showing advantages of being simple...
Quantum well infrared photodetectors based on the GaAs/AlGaAs material system where the aluminium mole fraction is below 0.45 are used for detecting long wavelength infrared radiation. By increasing the aluminium fraction these detectors can be made to detect shorter wavelengths as well, however this increase degrades detector performance. In this work we have studied a quantum well infrared photodetector...
Carbon nanotubes field emission displays are new type modern flat panel displays, its research work is based on development of NANO technology and carbon nanotubes. In order to simplify the fabricated processes for flat panel displays, the printed carbon nanotubes cathode is used to instead of the micro-tip which was made by silicon photolithography. The control and drive circuits, especially the...
The experimental fabrication of an all-fiber optical add-drop filter based on optical fiber Bragg grating assisted mismatched coupler using the fused biconical tapered technology is demonstrated. The full-width at half maximum of filter's bandwidth is 1.5nm, the side mode suppression ratio is better than 22dB, the echo power loss is -13.21dB and the drop filtering efficiency as much as 95.5% at 1553...
A hybrid optical filter based on long-period waveguide grating and multilayer medium thin film is proposed. The effects of the transmission spectra of the filter on the amplified spontaneous emission spectrum of Er-Yb codoped phosphate glass waveguide amplifiers are discussed. It's demonstrated that the flatness of below 0.5dB is achieved over a bandwidth of ~ 30 nm.
In this paper, we report on nonlinear spectral imaging of rabbit esophageal tissue, and ex-vivo human normal and neoplastic esophageal stroma. Our results show that nonlinear spectral imaging has a capability to identify the layered structures of epithelial tissue, and differentiate between normal and neoplastic human esophageal stroma.
Surface plasma wave excitation filters is used in the new photodetector in this paper. The detectivity is enhanced by excitation of surface plasma waves (SPWs) using a Metal Aperture Arrays grating. A bias-tunable broadband response is achieved.
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