A simulation method for visible and near infrared (VNIR) image is mentioned. The VNIR image obtained by low-level flight is adopted as data resource. After atmospheric correction, the ground reflectivity can be deducted. The simulation method consists of four steps: radiative transfer, spatial resolution, modulation transfer function, and noise simulation. The image of satellite-borne or high-level air-borne sensor could be generated by the simulation method from VNIR image. Experiment is carried out to test the method using an airship as platform. The resulting simulated image is compared to the image with quickbird panchromatic band. The result shows that simulation images enables one to effectively reproduce the entire process of remote sensing of the Earth. The method can be used to simulate VNIR image at satellite level at the same area and the same wavelength.

We study ⁸⁷Rb Bose-Einstein condensation (BEC) loading into the pulse of the one-dimensional (1D) optical lattice experimentally. The lattice is turned on abruptly, held constant for a variable time, and then turned off abruptly. The measurement of the depth of the optical lattice is obtained by Kapitza-Dirac scattering. The temporal matter-wave-dispersion Talbot effect with ⁸⁷Rb BEC is observed by applying a pair of pulsed standing waves (as pulsed phase gratings) with the separation of a variable delay.

We report the experimental achievement of ⁸⁷Rb Bose-Einstein condensation in a magnetic trap with microwave and radio frequency (RF) induced evaporation. Evaporative cooling is realized by using 6.8 GHz microwave radiation driving the ⁸⁷Rb atoms to transit from the ground-state hyperfine state |F = 2,mF =2> to |F = 1,mF = 1>. Compared with RF-induced evaporation, ⁸⁷Rb atoms are hardly to achieve pure condensate by microwave evaporation cooling due to the effect of atoms in the |F = 1,mF = 1> state being pumped back into the trapping |F = 2,mF = 1> state.

The influence of thermal effect on the energy conversion efficiency of concentrating photovoltaic system for multi-junction GaInP/GaAs/Ge thin-film solar cell is analyzed experimentally. With the increment of operation temperature, the maximal energy conversion efficiency and optimal loaded resistor will be changed. Under the condition of operation temperature lower than 90℃, this influence of thermal effect is very small. However, when the operation temperature exceeds 90℃, the maximal conversion efficiency of the cells will decrease sharply, and contrarily the corresponding optimal loaded resistor will increase quickly. Then the system performance will degenerate badly and a thermal management will be necessary.

A novel drug carrier based on SiO2-coated silver nanoparticle aggregates and antitumor drug is successfully synthesized. The surface-enhanced Raman scattering (SERS) spectra of the antitumor drug in living cells are obtained. By using silver nano-aggregates as SERS substrates instead of dispersed silver particles, a great improvement of SERS signal intensity is achieved. It is found that the chemical stability of the drug carrier can also be increased with the existence of SiO2 shell. The adsorbing effect between antitumor drug 9-aminoacridine (9AA) and silver particles is investigated to optimize the SERS signal. The core/shell structure of the drug carrier is characterized by ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM) pictures. The experimental results show that the drug carrier offers biocompatibility, stability, and high SERS activity, holding the potential for realizing the intracellular drug tracing.

Compared with the traditional image intensifier with phosphor screen readout, the photon-counting imaging detector with charge induction readout is more beneficial in several aspects (e.g., good imaging properties and time resolution) to astronomy, reconnaissance, bioluminescence, and materials research. However, the annealing temperature during the tube-making process can affect the properties of the Ge film, and consequently impair the performance of the detector. Therefore, the influence of annealing temperature on Ge film and on the detector is studied in order to determine the crucial parameters. The Ge films are prepared on ceramic and quartz glass by the use of an electron gun. They are analyzed by scanning electron microscope (SEM), high-resistance meter, and X-ray diffraction (XRD). The results show that the optimum substrate and annealing temperature are ceramic plate and 250 ℃, respectively.

Gain saturation is a significant phenomenon of fiber Raman amplifiers (FRAs). Gain figures versus signal power are well explained. For the small signal, the coupled ordinary differential equations are used, and for the large signal, the Raman gain coefficient is modified. It is shown that the saturation power of FRAs decreases with the pump power, and gain saturation is easier to occur in the forward pump scheme than in the backward pump scheme. These phenomena are well explained by the stimulated Brillouin scattering (SBS) effect. This research provides a guide to the fabrication of practical FRAs.

We propose a wavelength conversion scheme for chaotic optical communications (COC) based on a Fabry-Perot (FP) laser diode. The FP laser, as a wavelength converter, is injection-locked at one of longitudinal modes by an external continuous-wave (CW) light. The simulation results demonstrated that the chaos masked signal at wavelength \lambda1, which corresponds to the other longitudinal mode of FP laser, can be converted to the injection-locked mode (wavelength \lambda 2) based on cross-gain modulation in a closed-loop COC link. A 1.2-GHz chaos masked sinusoidal signal is successfully decoded with signal-to-noise ratio (SNR) beyond 8 dB in 15-nm wavelength conversion range, and the effects of SNR on the signal frequency and conversion span are also investigated.

A contention resolution scheme, P-cycle auto-switching (PCAS), is proposed in wavelength-switched optical networks (WSONs) based on generalized multi-protocol label switching (GMPLS) to solve backward blocking. This system permits the preferable request and switches the other to a backup path generated by the P-cycle. Simulation results show that the PCAS scheme is effective in mitigating backward blocking, especially under concentrated load.

A cost-effective method of multi-receiver optical orthogonal frequency-division multiplexing (OOFDM) system is proposed to reduce the requirement for the speed of the receiver and the size of fast Fourier transform (FFT). The sampling rate of analog-to-digital converters (ADCs) can be reduced to 1/N of the original signal bandwidth in an N-receiver system. Aided by signal predistortion at the transmitter, aliasing-free signal can be retrieved independently and directly at the low speed receivers. A back-to-back experimental result is given for a two-receiver system. The effect of the electrical filters added before the ADC is studied and the analysis for filters optimization is given.

A new image coding approach is proposed by controlling the quantization step via minimizing the perceptual distortions (in terms of image’s contrast measurement). The proposed method is a rate-oriented contrast-based approach, which is in contrast to the conventional quality-oriented contrast-based image coding. The algorithm achieves a higher perceptual quality performance against several methods developed previously.

A new multispectral image fusion method based on intensity-hue-saturation (IHS) transform and three-channel non-separable wavelets whose dilation matrix is [2,1;–1,1] is proposed. The multi-resolution decompositions of the intensity of multispectral image and panchromatic image are performed in nonsubsampled mode using the three-channel non-separable wavelet filter bank. The approximation images and the detail images of the multi-resolution pyramids are fused. The experimental results show that this method has good visual effect. The performance outperforms the IHS fusion method, the discrete wavelet transform (DWT) fusion method, and the IHS-DWT fusion method in preserving spectral quality and high spatial resolution information.

A novel radiometric compensation algorithm is proposed to correct the color distortions of the projection display on patterned surface. Two choices of the objective image are investigated in this algorithm. A linear compression followed by a sigmoid-function transformation based on the statistical parameters of the compensating radiance map is performed to reduce the clippings of the compensating color and expected to properly reproduce the dynamic range and the visibility of the image content. Three types of projection displays are produced for each test image. The parameter analysis indicates that the compensated displays could well conceal the surface pattern and tend to exhibit higher lightness or lightness contrast in the camera. The comparison results in a psychophysical experiment demonstrate that all the compensated displays outperform the uncompensated ones. The original input images seem more appropriate to be selected as the objective images, and the predicted objectives on the white screen are just proper for the bright and low-contrast input images displayed on the faint surface.

A novel fiber optic Fabry-Perot (F-P) current sensor is developed based on magnetic fluid as the medium in F-P interference cavity. A signal demodulation method based on slanted fiber Bragg grating (FBG) wavelength measurement system is proposed. Theory and principle of electromagnetic-controlled refractive index of the magnetic fluid is described, as well as the structure of the sensor system. Preliminary experiments are carried out, and the results indicate that there is a fairly good linearity of the measurement characteristic. The thickness of magnetic fluid film and initial concentration will affect the measurement results.

The liquid crystal thermography is a high-resolution and non-intrusive optical technique for full-field temperature measurement. We present detailed calibration data for a wide-bandwidth thermochromic liquid crystal (TLC) to investigate the effect of the coating thickness on the hue-temperature characteristics and the measurement uncertainty of the TLC. It is found that the coating thickness has appreciable effect on the TLC hue-temperature curve. For TLC coatings with the thickness over 20 μm, a thicker TLC coating shows a relatively smaller measurement uncertainty, but the effect of the coating thickness is non-distinctive on the measurement uncertainty.

A novel method to measure the effective cavity length of distributed Bragg reflector (DBR) fiber laser with fiber Bragg grating (FBG) Fabry-Perot cavity as the resonator is proposed. The effective cavity length of DBR fiber laser is accurately measured by measuring the frequency spacing of two adjacent longitudinal modes in the cavity without the precise physical length of FBGs. The measuring accuracy as high as 10^-5 mm can be obtained by setting the resolution bandwidth of the spectrum analyzer.

A high power optically-pumped vertical-external-cavity surface-emitting laser with a diamond heatspreader is demonstrated. Owing to the good thermal conductivity, diamond can accelerate the dissipation of heat in the active region and increase the output power significantly. The effects of the curvature radius, the transmission of output coupler, the spot size of the pump, and the temperature of the heat sink on the output power are investigated. A maximum output power of 880 mW is obtained under the conditions of 10℃ temperature, 15-mm curvature radius, 3% transmission of the output coupler, and 8500-mW pump power. The slope efficiency and the optical-to-optical conversion efficiency of the laser are about 17% and 15%, respectively.

A high power all-fiber laser is experimentally studied. A monolithic fiber laser system with only one stage of resonator cavity is constructed and 404-W continuous wave (CW) output power is obtained. Its opticalto-optical conversion efficiency is up to 64%. The laser central wavelength is at 1081 nm with the spectral full-width at half-maximum (FWHM) of 2 nm. The laser setup can work with excellent stability; in the long time of high power operation, no thermal distortions or damages are observed.

An automated damage diagnostic system for collecting plasma flash is developed to diagnose damage in a laser-induced damage threshold (LIDT) test system. Experiment is done to verify the accuracy of this system and analyze the relationship between the plasma signals and the damage morphologies. The results obtained by the system are found to be in excellent agreement with those obtained by the much laborious method of Normaski microscope. Results show that plasma signals above 1 V correspond to the damage morphology of surface discolorations with or without pits in their centers, and plasma signals below or just around 1 V correspond to the damage morphology of pits. The misdiagnosis is attributed to contaminations and air breakdown.

A high energy pulsed terahertz (THz) laser is studied experimentally. The laser cavity simply consists of a quartz glass waveguide, a coated GaAs input window, and a crystal quartz output window. NH₃ is filled in the cavity as gain medium, and pumped by an 8-J line-tunable transversely excited atmospheric (TEA) CO₂ laser. When 9R(16) transition acts as the pump line, 55.6-mJ THz radiation (90 \mu m) is obtained at 730-Pa NH₃ pressure. The corresponding conversion efficiency is 13.54%. Energy and optimal pressure of amplified spontaneous emission and laser oscillation are compared.

The growth of a Mn-doped LiAlO₂ single crystal by the Czochralski (CZ) method and the characterization of its spectroscopy and thermoluminescence (TL) are presented. The X-ray rocking curve and chemical etching analysis show that the as-grown crystal has good crystallinity. The full-width at half-maximum (FWHM) of the LiAlO₂ (200) \omega rocking curve is 23.2 arcsec and the etching pits density of the (100) plane is (1.6–4.0)×10⁴ cm^-2. The transmission spectrum indicates that the crystal is highly transparent in the 200–1500-nm wavelength range. The emission spectrum of the crystal consists of a peak around 579 nm when excited with 428-nm light. The TL spectra show that the LiAlO₂:Mn crystal has glow peaks at 150 and 172 ℃. The change of TL characteristics of the crystal before and after thermal annealing in the air is discussed, and the effect of annealing and irradiation on the evolution of defect types is analyzed.

Using the optical coherence tomography (OCT) images, the optical attenuation coefficients (\mu t) of human Laogong acupoint and non-acupoint tissues are measured after empty irradiation and 808-nm 100-mW irradiation for 10 min in vivo non-invasively. The results show that there is no significant difference of \mu t of Laogong acupoint and non-acupoint tissues after empty irradiation. However, there are significant differences of \mu t between Laogong acupoint and non-acupoint tissues after laser irradiation at the power of 100 mW (statistical definition of probability p < 0.01). The results of the pilot study indicate that the OCT could distinguish the acupoint from the surrounding tissues after irradiation with laser in vivo non-invasively.

A problem in terms of the accuracy of noninvasive measurement of blood glucose with near-infrared (NIR) spectroscopy is mainly caused by the weak glucose signal and strong background variations. We report the existence of the radial reference point in a floating-reference method, which is supposed to solve this problem. Based on the analysis of the infinite diffusion theory, the local condition of the reference point is deduced theoretically. Then the experiments using the intralipid solutions are constructed to testify the existence of the reference point. In order to further validate our results, Monte Carlo simulations are performed to calculate the diffused light distribution according to the variation of the glucose concentration in the intralipid solutions. All the reference points existing in three-layer skin model are also listed at the wavelength of 1200-1700 nm.

Cr ion implantations in glass with the different doses of D=1.493×10¹⁷ and 4.976×10¹⁷ ion/cm² are obtained by metal vapor vacuum arc (MEVVA). The effects of the different Cr ion implanted doses on terahertz (THz) transmission property are analyzed from THz time-domain spectroscopy. The results show that the more the Cr ion implanted dose in the micro-area implantation glasses, the larger the THz transmission except the larger absorption at 0.24 THz. This is an effect attributed to the coupling of plasmas on both the implantation and the implantation affected zones of the Cr ion implantation glass.

We analyze the random disturbance in the transmission of light through a spinning Glan-Thompsontype prism polarizer. The disturbance makes the dependence of the transmission on the rotation angle significantly deviates from the Malus cosine-squared law and severely spoils the output light quality. Slight vibration of the polarizer as it rotates combing the multi-beam-interference effect raises the disturbance. Further analysis reveals the sensitive dependence of the disturbance on the composing material of the prism gap, and the appropriate selection of such material can make the disturbance minimize to very desirable levels. The model results show quite good agreement with experiments.

We demonstrate a photonic band gap (PBG) from one-dimensional (1D) periodic structures created by a double-layer unit cell with an air layer and an anisotropic nonmagnetic left-handed metamaterial (LHM) layer whose permittivity elements are partially negative. The requirements imposed on the materials and structures to realize a PBG are derived when the frequency is above or below the cutoff frequency, and the transmission properties of the PBG are discussed by utilizing 4×4 transfer-matrix method with dispersive semiconductor metamaterial.

A new organic-inorganic hybrid material, which shows photo-induced reduction of refractive index as well as volume contraction, is prepared using a sol-gel method. This material is coated on a Si substrate by spin-coating to manufacture film. After irradiated by ultraviolet (UV) light with a deuterium lamp for 5 h, the thickness of film decreases largely by 55%, and the refractive index of film changes from 1.484 to 1.445 at 550 nm. The film’s optical thickness exhibits an exponential change with the increasing irradiation time. Futhermore, the photo-patternning of the organic-inorganic hybrid film without any further process (wet etching and thermal curing) is performed utilizing the volume contraction on UV-light irradiation. This film has potential applications for fabrication of patterned filter array and apodizing filter by direct light writing, and also demonstrates good temperature stability and immunity to visible light exposure.