Based on the experimental researches on the fluorescence spectra of 1% erythrocyte solution with various concentration of alcohol excited by violet light-emitting diode LED light at 407 nm, the mechanism of alcohol on the fluorescence spectra of erythrocyte solution is investigated theoretically. The experiment results indicate that induced by the LED light at 407 nm, erythrocyte solution with the concentration of 1% can emitting striking spectra with two fluorescence regions. One is the short-wave fluorescence region from 430 to 525 nm, and the other is the long-wave fluorescence region from 580 to 750 nm. When the concentration of alcohol in erythrocyte solution increasing, the fluorescence intensity of short-wave area decrease while the fluorescence intensity of long-wave area increases. Combining the blood absorb spectra to the experiment results, it is shown that the formation of the short-wave fluorescence area is because the solution transmits the fluorescence spectra and the self-absorption of erythrocyte. The long-wave fluorescence region comes from porphyrin such as protoporphyrin, zinc porphyrin etc.. And there is resonance energy transmission between the short-wave fluorophores and the long-wave ones. According to the experiment results and the physical theory in erythrocyte fluorescence, it is found that alcohol make higher self-absorption ratio of the erythrocyte which improves the resonance energy transmission between fluorophores in the two wave bands. The result will offer experimental and theoretical reference for examining the alcohol content in blood.

The principle of the algorithm for stability near infrared (NIR) optical Tomography (CT) is introduced. The forward problem of optical CT is how to solve the Boltzmann transmitting equation based on finite rlement method (FEM). The influence of high reduced scattering coefficient and high absorption coefficient distribution of simulation background was discussed. The inverse problem is to reconstruct the map of the background tissue from the boundary data, and the image reconstruction algorithm is the key problem for optical CT. Generic algorithm (GA) and FEM simulation was used to solve the inverse problem.

Varietal purity is the most important quality parameter of maize seeds, which has direct and prominent influence on the output and quality of maize. For the first time, to our knowledge, we present a new kind of terahertz (THz) scanning imaging technology for identification of maize seeds. Terahertz images of DNA samples are obtained by point-by-point scanning imaging technology. Inspection and identification of specific kinds of seeds are realized successfully by using the method of component pattern analysis. In this method, what we need are only data of image and absorption spectral information of samples; no specific features of samples are required. This technology provides a new approach for the detection and identification in biology and it can also be extended to poison inspection.

ZnO is an n-type semiconductor having a hexagonal wurtzite structure. By X-ray diffraction (XRD) and scanning electron microscope (SEM), the influences of substrate temperature, the ratio of Ar to O2 and thermal temperature on ZnO crystal quality were studied. The results show that ZnO films deaposited at substrate temperature of 240 Celsius degrees and Ar:O2=1:3 have the best crystallization. UV photoluminescence is observed when ZnO films are excited by He-Cd laser at room temperature. Stress at boundary causes an intrinsic UV emission peak shift to the lower energy. Oxygen vacancy or zinc interstitial causes deep-level emission. With higher substrate temperature, the crystallization is improved and the stress and deep-level green emission are reduced.

We systematically investigate a strain of self-assembled InAs/GaAs quantum dots (QDs) for the case of growth on a (001) substrate. The dependence of the biaxial and hydrostatic components of the strain on the quantum dot aspect ratio is studied using a finite element method. The dependence of the carrier's confining potentials is then calculated in the framework of eight-band kp theory. The shifts of the energy level in three shapes of QDs are investigated. By comparing the results, the influence of the strain on the QDs are given.

In this paper, the p-i-n multiple-layer Al_(x)Ga_(1-x)N sample with high Al (x>0.45) content was measured by the triple-axis X-ray diffraction measurement. The strain state and screw dislocation density of each layer in Al_(x)Ga_(1-x)N epitaxial layers were determined by RSM (reciprocal space map) method. Then, the PV function was used to fit the rock curves separated from the RSM. At last, the strain and the screw dislocation density of each layer were accurately calculated by fitting these rock curves.

The third-order nonlinearities of PbS nano-belts have been investigated using the Z-scan technique with nanosecond laser pulses at 532 nm. The effect of the PbS semiconductor nano-belt size on the third-order optical nonlinearities and optical limiting properties was studied. We found that the nonlinear absorption and nonlinear refraction have not strict dependence on the nano-belt size under our investigated condition, but their optical limiting behavior is different. The optical limiting mechanism of materials is discussed.

Using numerical simulation method based on finite-difference time-domain (FDTD), we study the characteristics of the multiple-core photonic crystal fibers (PCFs) in which square-nested compound lattices (SNCLs) with several defect regions are introduced. We find that each line defect in the PCFs can serve as a channel in wavelength division multiplexing (WDM) communication systems. The crosstalk can be suppressed because there is a band gap among each channel in the PCFs. And PCF amplifiers are expected to be used in the super-dense WDM systems.

The optical properties of carbon nanotubes are studied. Align carbon nanotubes films were synthesized by chemical vapour deposition method in our lab. The diameter of carbon nanotube is about 20-30 nm. The amorphous carbon impurities in align carbon nanotubes film were removed by a series of deal with processes. Carbon nanotubes were examined up by using scanning electron microscope, transmission electron microscope and Raman spectrum.The reflected spectrum, transmission spectrum and absorption were measured. Results show that carbon nanotubes have strong absorption from visible region to mid-infrared (IR) region. Photoluminescence spectra of carbon naotubes film were studied at 488, 632.8, and 1060 nm excited laser wavelength. Results show sthat there are nonlinear processes in luminescence of carbon nanotubes under ultrafast laser excitation (1064 nm, 60 ps) conditions. A broad photoluminescence peak was location at 1.6 eV (about 768 nm), this phenomenon was considered to relate to van Hove singularities, and was a three-photon-absorption process.

In single-particle tracking (SPT), fluorescence video microscopy is used to record the motion images of single particle or single molecule. Here, by using a total-internal-reflection microscope equipped with an argon ion laser and a charge-coupled device (CCD) camera with high-speed and high-sensitivity, video images of single nanobeads in solutions were obtained. From the trajectories, the diffusion coefficient of individual nanobead was determined by the mean square displacements as a function of time. The sizes of nanobeads were calculated by Stokes-Einstein equation, and the results were compared with the actual values.

The nanoparticles ZnO had been prepared on the surface of ZnS:Cu by homogeneous precipitate method. The urea was used as precipitator in the process of hydrolysis reaction. X-ray diffraction (XRD) and infrared (IR) spectra indicated that ZnO was formed. We also observed fluorescence spectra, there was some difference between the raw material and coated materials in fluorescence intensity.

The mechanical properties of fluorescent microtubules (MTs) are probed with dual-optical tweezers system. The results indicate that the fluorescent MTs are much easier to be extended compared with those without fluorescence. Such MT can be extended by 30% and force for breaking up it is only several piconewtons. Furthermore, we find that the breakup of the protofilaments is not simultaneous but step-by-step. Finally, the mechanism of the breaking is discussed.

The surface morphology is one of the important factors to determine the optical properties of colloidal quantum dots. Colloidal CdSe dots were synthesized by the injection of precursor molecules in a hot surfactant, and a series of samples were obtained by partially replacing the ligands on the surface of these dots with 2-mercaptoethanol. 2-mercaptoethanol results in the decrease of the photoluminescent quantum yield, and the time-resolved photoluminescent (PL) spectra are significantly modified. The effect of the surface morphology is discussed.

We investigate the dynamics of photonic crystal (PC) molecules with Kerr nonlinearity by numerical simulations in a pump-probe scheme based on the finite-difference time-domain technique. The constitutional PC atoms of the nonlinear PC molecules are intentionally chosen to be multimode so that the pump and probe waves can be set at different frequencies, ensuring the clear identification of the dynamics of nonlinear PC molecules. Being more complicated than the dynamics of nonlinear PC atoms, we reveal that the coupling between the PC atoms plays an important role in determining the dynamical responses of nonlinear PC molecules to the excitation of ultrashort pulses. It is reflected in fact that PC molecules with different spectral shapes exhibit different dynamical response behaviors.

Bandgap and defect mode are important properties of two-dimensional (2D) photonic crystal, which determine the application of photonic crystal. At present, researchers have done a large amount of studying on point defect and line defect photonic crystal. In this paper, we introduce multi-point defects into 2D photonic crystal by removing medium rods (InGaAsP), and then simulate their bandgap and mode field using plane wave method (PWM). The simulation results are useful to design the multi-wavelength photonic crystal laser.

A scheme is proposed to implement quantum state transfer between two distant atoms through sending the atoms across two distant cavities connected via an optical fiber. The field state, which preserves the information of the first atom, is transmitted from one cavity to the other along the fiber. After the field interacts with the second atom for a defined time, the state transfer can be accomplished with unit efficiency. The realization of this scheme is within current experiment technology.

The probe absorption spectrum of a four-level atom embedded in a double-band photonic crystal is discussed in this paper. The double V-type transitions from the two upper levels to the two lower levels interact with the free vacuum modes and the photonic band gap (PBG) modes synchronously. We investigate the quantum interferences in the probe absorption spectrum. And the new features of transparency are also predicted.

We present two novel 1*N dynamic optical couplers that are based on Dammann gratings to achieve dynamic optical coupled technology. One is presented by employing a specially designed Dammann grating that consists of the Dammann-grating area and the blank area. The other is developed by using two complementary even-numbered Dammann gratings. The couplers can achieve the function conversion between a beam splitter and a combiner according to the modulation of the gratings. We have experimentally demonstrated 1*8 dynamic optical couplers at the wavelength of 1550 nm. The experimental results and the analyses are reported in detail.

Research of the first-order Raman fiber laser pumped by a continuous wave (CW) fiber laser is presented using domestic Bragg gratings with corning SMF-28TM silica fiber as the gain material. Formation process of Raman laser is studied and output characteristics are measured. Laser output is centered at 1116 nm with 3-dB bandwidth of 0.18 nm. Pump threshold is estimated, which is in good agreement with the experimental value by revising the equation in some references. Techniques for decreasing threshold power and increasing output power are also analyzed.

Nonlinear optical materials adopting optoelectronics elements are required to have a third-order nonlinear optical susceptibility of 10^(-9) order [esu]. However, the relationship between nonlinear optical characteristics and the morphology of the meal-phthalocyanine thin film prepared on alkali-halide substrate remains unclear. Therefore, the growing process of vanadyl-phthalocyanine (VOPc) thin films fabricated on alkali-halide substrate were investigated by UV/Vis spectra, AFM images, and the incident angle dependence of second harmonic (SH) and third harmonic (TH) intensities measured by Marker fringe. It is recognized that VOPc thin film prepared on KBr (100) is an island-like growth, on KCl (100) it is step-terrace growth.

We investigate the coupling characteristics in dual-core photonic crystal fibers (PCFs) with elliptical air holes and their applications in the construction of polarization splitters by use of a full-vector beam propagation method. The numerical simulation results indicate the possibility of realizing a polarization splitter with an extinction ratio better than -20 dB at 1.55 microns and a total length of only 1.651 mm. It is also revealed that the total length of the polarization splitters can be further reduced by properly doping the core regions of the PCFs.

A model of a structure consisting of nonperiodic closely spaced metal nanoparticles array, in which electromagnetic energy can be transported and splitted below the diffraction limit, is founded. Based on finite difference time domain (FDTD) algorithm, we analyze the power transmission properties of nonperiodic silver nanoparticles arrays in a dielectric waveguide. The numerical results indicate the structure can split light along the array at the nanometer level with no radiative losses at the discontinuity.

We propose a protocol where one can realize quantum cloning of an unknown two-particle entangled state and its orthogonal complement state with assistance offered by a state preparer. The first stage of the protocol requires usual teleportation using a (or two) four-particle entangled state(s) as quantum channel(s). In the second stage of the protocol, with the assistance (through a two-particle projective measurement) of the preparer, the perfect copies and complement copies of an unknown state can be produced.

Polymer films thickness is one of the critical factors for the operation performance of the integrated optical devices (IODs) based on polymer planar waveguides and it is difficult to real-time determine it during corresponding fabrication process. A variety of approaches, which have been presented before, are either of less precision or more contamination of the film surfaces. In this paper a practical method, in which the absorbance of the polymer film using Lanbert law to determine the thickness of spin-coated polymer films, was presented. Compared with other methods, it can get an acceptable accuracy without using specialized and expensive instruments, and the surface of the film with not be contaminated during the measurement process. The experimental results compared with other methods were listed and depicted in confirming our method's availability. The factors that may have influence on the employment of our method were analyzed and discussed.

A triple-layer light-emitting diode based on an organic salt ASPT (trans-4-[p-[N-methyl-N-(hydroxyethyl)amino]styryl]-N-methylpyridinium tetraphenylborate), in which TPD and Alq3 were employed as hole and electron transporting materials respectively, exhibits variable electroluminescence (EL) spectra under different applied voltage. At lower voltage, the EL spectrum peaks at 560 nm, which emanates from the TPD/ASPT interface; when the voltage is further increased, the peak at 610 nm, which is originated from ASPT, increases; at higher applied voltage, the device yields green light with a peak at 530 nm and a shoulder at 610 nm. The stronger emission peaking at 530 nm stems from the Alq3. It reveals the hole-electron recombination zone depends on the applied voltage, so the color-variable EL can be observed by adjusting the applied voltage.

Two-color holographic recording was performed in near-stoichiometric LiNbO3 crystals doped with 50-ppm Mn, where the crystals were thermally annealed in different oxidation/reduction atmospheres. Two-color recording properties including sensitivity, dynamic range, activity energy, and dark decay time were measured and compared, and the results were explained reasonably by measuring some characteristic material parameters.

The free photoelectron signals of spectral sensitized AgCl emulsion with different sensitization concentrations are obtained from microwave absorption dielectric spectrum experiment. It is found that when sensitization concentration is small (0.04 mg dye per 40 g AgCl emulsion) or great (4 mg dye per 40 g AgCl emulsion), the decay of free photoelectron of sensitized emulsion is slower or faster than that of pure emulsions; when sensitization concentration is between the above values (0.4 mg dye per 40 g AgCl emulsion), the decay of free photoelectron is the same for sensitized and pure emulsion. The results indicate that the adsorbed green-sensitizing dye on the surface of cubic AgCl microcrystals takes on different actions with different sensitization concentrations.

The polyimide-silica nonlinear optical (NLO) hybrid materials with covalent links between the inorganic and the organic networks were synthesized by the sol-gel method. The prepared hybrids were characterized by IR, TGA, XRD, SEM, TEM and can be easily spin-coated, ensuring long-term alignment stability at elevated temperatures. These devices exhibit large electro-optic coefficients at 832 nm. The experimental results suggest that the hybrid thin films have potential applications as passive films for optical devices.

Two-photon absorption (TPA) cross sections of an organic dye, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium iodide (abbreviated as ASPI), from 810 to 1100 nm have been measured in two solvents (benzyl alcohol, dimethyl formamide (DMF)) with different polarities. The peak values and positions of ASPI TPA spectra were found to be strongly influenced by the solvents. The maximum molecular TPA cross sections are 26.42*10^(-48) cm4 s/photon at 930 nm (in DMF solution) and 46.81*10^(-48) cm4 s/photon at 960 nm (in benzyl alcohol solution).

The new chromophore molecules with nonlinear optical (NLO) properties were prepared by Knoevenagel condensation from diformyl calix[4]arene and isophorone derivatives in the presence of piperidine and acetic acid, respectively. In these chromophore calix[4]arenes, the ring-locked trienes were employed as the conjugation bridge and electron acceptor in D-'pi'-A units. Nuclear magnetic resonance (NMR) spectra indicate that the non-conjugated D-'pi'-A units can be oriented at nearly the same direction. Hyper-Rayleigh Scatting (HRS) measurements and ultraviolet (UV) spectra indicate that they have higher first hyperpolarizability 'beta' values than the corresponding reference compounds and are not accompanied with a large shift (>25 nm) of the absorption band to longer wavelengths.

Laser ultrasound is a technique based on lasers to generate and detect ultrasound remotely. The thermal expansion arising from the optical absorption of a short laser pulse generates ultrasonic wave. By using finite element method, this study presents a source model for laser ultrasonic generation in thin transversely isotropic laminate composite in the thermoelastic regime. According to the thermoelastic theory, the transient temperature is equivalent to a body source to generate ultrasonic waves. The numerical results indicate that the symmetric and antisymmetric Lamb wave is excited in thin transversely isotropic laminate composite plate, the evolution of the dispersive waveform is a function of the source-receiver distance, the plate thickness, and the parameters of the fiber-reinforced composite. These results are very useful for evaluation materials parameters of the composite plate.

The passively quenched operation of avalanche photodiode (APD) has been used to characterizing InGaAs/InP APD including punch through voltage, avalanche voltage and break down voltage that are all important in the design of APD for single photon detection. The punch through voltage at certain doping level can be related to the thickness of the InP multiplication layer and the thickness of the un-intentionally doped n-type InP layer can be adjusted in according to the experimental data. The analysis indicates that the punch through voltage should be close to the breakdown voltage that can be realized by adjusting the thickness of InP multiplication layer.

Microwave absorption and dielectric spectral detection technology with high time resolution (1 ns) is used for contactless measurement of electron property in solid materials. In this paper, the free photoelectron time-resolved spectra of cubic AgCl emulsion sensitized by green-sensitizing dye are measured by dielectric spectral equipment. The samples are exposed to 35-ps short pulse laser at 355 and 532 nm, respectively. The results show that for the same sensitized sample, the free photoelectron lifetime are 43.1 and 5.8 ns, respectively. And for the same wavelength, the lifetime of sensitized emulsion is shorter than that of pure emulsion. It is thus proved that the adsorption of dyes to silver halide microcrystals increases the Ag_(i)+ concentration.

A new nano-meter scale resolution optical imaging mode and functional prototype of photon scanning tunneling microscope (PSTM) combined with atomic force microscope (AFM) named as AF/PSTM are introduced, and the advantages of AF/PSTM are discussed. Two separated optical images (refractive index image and transmissivity image) and two AFM images (topography image and phase image) of sample can be obtained during AF/PSTM's once scanning. AF/PSTM is applicable to all transmission samples in many fields, such as nano-biology, medicine, nano-optics, nano-industry, nano-science and technology, high-education and so on.

AF/RSNOM is a new kind of scanning probe microscope developed in our lab, which is a combination of atomic force microscope and reflection scanning near field optical microscopy (AF/RSNOM) working in equi-amplitude tapping mode. This paper introduces the principle of AF/RSNOM and its advantages compared with other reflection mode scanning optical microscopes (RSNOM). Compared with the former RSNOM, this tapping mode AF/RSNOM has convenient operation and fewer background signals.

The imaging technology of stimulated emission depletion (STED) utilizes the nonlinearity relationship between the fluorescence saturation and the excited state stimulated depletion. It implements three-dimensional (3D) imaging and breaks the diffraction barrier of far-field light microscopy by restricting fluorescent molecules at a sub-diffraction spot. In order to improve the resolution which attained by this technology, the computer simulation on temporal behavior of population probabilities of the sample was made in this paper, and the optimized parameters such as intensity, duration and delay time of the STED pulse were given.

A novel measurement system for the gas density based on spectrum absorption is studied in details. Based on the theory of Beer-Lambert, the technology of nonlinear laser diode (LD) spectrum is used to perform the polluting gases monitoring on line. The peak wavelengths of LD are changed with the applied voltage and temperature, so the technology of wavelength modulating or frequency modulating can be used at perform the measurement in wide scope. In this paper, the low density of the polluting gases, is detected by the method of harmonic detection in order to increase the detection sensitivity.

Optical coherence tomography (OCT) suffers from random noises which degrade contrast of image, these noises can not effectively be wiped off by filtering technique. Characteristics of random noises were discussed and analyzed, noise influences were identified on image. The method of wavelet transform is presented for image denoising. The result shows that the method can reduce image noises.

Steady-state diffuse reflectance based on P3 approximation is studied at short source-detector separations. In many practical applications, we can only measure the diffuse reflectance light close to the source, and attempt to derive the optical parameters of tissues from the collected data. In this paper, diffuse reflectance with different absorption coefficients and scattering coefficients at short source-detector separations is measured, and the experimental results are compared with that of P3 approximation. These studies show that P3 approximation can be used to describe the light contribution close to the source, and can be used to study strong absorption medium.

In the field of nondestructive evaluation, laser generation and detection of the surface acoustic waves (SAWs) are potentially useful for investigating material surfaces. SAW generated by laser line source is carried out on a kind of optical difference detection system based on optical beam deflection technique. The setup is simple and easy to adjust. Furthermore the system has advantages such as high efficiency of photo-electricity conversion, high frequency responding, the ability of ant-intervene and broadband detection etc.. It can be used not only to receive SAW, but also to detect surface-breaking defects in material. The experimental results verify that the SAWs generated by a line source have the advantages of powerful signal and good directivity. SAWs have been excited on sample aluminum with artificial surface-breaking defects. From the experiment, we attain the characters of reflected wave and transmitted wave by SAW interacted with the surface-breaking defects.

In order to further confirm the relations between the size of internal defect and the measured ultrasonic signals and understand the interaction mechanism between the ultrasonic wave and inside defect, this paper has constructed the two-dimensional (2D) plane strain finite element model of the Al plate with the inside defect to simulate the scattering process of the ultrasonic wave generated by the pulsed laser in the Al specimen. The dependence of the normalized amplitude of the defect signal on the defect diameter has been calculated in details, and the ultrasonic reflectance by the cylindrical shaped internal defect was evaluated in details using the numerical results. It is demonstrated that the laser ultrasonic technique has the ability to detect the sub-millimeter-scale internal defects in industrial components and engineering structures.

The improvement of the generation efficiency has attracted much attention, confronted with the little amplitude of acoustic wave generated by pulsed laser in the thermoelastic regime. This paper constructed the finite element model to simulate ultrasonic waves generated by the ring-shaped laser source with the 8 mm inner radii. The numerical results demonstrate that strong focusing exists at the center axis of ring as the result of constructive interference of the waves generated by different parts of the source. Furthermore, the bulk wave includes compression, shear peak amplitudes and the surface acoustic wave magnitude drops quickly when the receiver position is away from the epicenter. Numerical simulations indicated that the low acoustic amplitudes in laser acoustics can be relieved somewhat by taking advantage of constructive interference between waves generated by different parts of an acoustic source, giving locally higher amplitude.

Frequency resolved optical gating (FROG), is an effective technique for characterizing the ultrafast laser pulses. The multi-shot second harmonic generation (SHG) FROG is the most sensitive one in different FROGs. In this paper we use this technique to measure the femtosecond optical pulses generated by a conventional Ti:sapphire oscillator.

The excited state absorption and optical limiting of a series of platinum(II) 4'-arylterpyridyl acetylide complexes have been investigated. These complexes possess relatively long triplet excited state lifetime that varies from tens of nanoseconds to several microseconds; and exhibit broad triplet excited state absorption in most of the visible to near infrared spectral region. Nonlinear transmission experiments demonstrate that all of the complexes show pronounced optical limiting for ns laser pulses at 532 nm. The photophysical properties and optical limiting characteristics are influenced significantly by the nature of 4'-aryl substituent and the acetylide ligand.

To achieve detection, monitoring, and automation of starch graft copolymerzation at any time, the investigation is being made according to luminescence of free radicals produced in the reaction. The investigations on the fluorescence spectra of starch-water suspension excited by ultraviolet (UV) light and its characteristics contribute to study the characteristics and mechanisms of free radicals coming into being, emitting, and disappearing. Fluorescence spectra of starch, dextrose, sucrose, and maltose excited by 260-nm light are compared and their similarities further verify that this fluorescence comes from the transition from nonbonding, namely n electrons in the hetero-atom (O) of the functional group (C-O-C) called ether linkage, to the antibonding orbital 'sigma'*. The functional group is a part of six-membered ring structure in starch molecule. Meanwhile, the experimental results indicate that relative peak intensity of fluorescence emitted by 1% starch suspension comes to climax when starch suspensions with different concentrations are excited by the same wavelength.