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To explore the physiological response characteristics of plant photosynthesis under acid precipitation stress (A stress), snow-melting agent stress (S stress), and freeze-thaw stress (F stress) as well as their various combinations, the net assimilation rate (NAR), intercellular CO2 concentration (Ci), stomatal conductance (Gs) and water use efficiency (WUE) of tall fescue (Festuca arundinacea Schreb.) under these three stresses respectively and four kinds of combined stresses were measured. The effects of these different kinds of stresses on the photosynthesis parameters were then evaluated, and the major mechanisms of main factors affecting the interactions between stresses were speculated. The experimental results indicated that both NAR and WUE decreased significantly in response to all stresses and Ci increased dramatically in response to all stresses, while Gs ascended under F stress but descended in response to A stress and S stress. The photosynthetic efficiency significantly decreased as the temperature decreased and did not clearly recover as the temperature increased. Moreover, the combination of A stress and S stress had fewer effects on photosynthesis than did the S stress alone, while the effects resulting from F stress were similar at low temperature. The major controlling mechanism is most likely the strong inhibition of photosystem II and the promotion of antioxidant enzymes resulting from acid precipitation as well as NaCl may strengthen the freezing tolerance of plants. [ABSTRACT FROM AUTHOR]

We report a compact all-solid-state mid-infrared optical parametric oscillator with wide tunability using periodically poled 5 mol % MgO-doped LiNbO3 with a multiple-channel structure design and pumped by a compact diode-pump solid-state laser operating at 1.064 μm. Wide tunability from 1.44 to 1.58 μm at the signal beam wavelength and from 3.28 to 4.11 μm at the idler beam wavelength was achieved by both varying the temperature and translating the crystal through the resonator and the pump beam with no realignment required. The tuning performance and its related factors were analyzed, and at the same time the output performance as well as the effect of mid-infrared absorption of idler beam was investigated. [ABSTRACT FROM AUTHOR]

A scatheless visualization has demonstrated that the engineered and spontaneous domains of lithium niobate (LiNbO3) crystal can be delineated by means of the nanoparticle decoration. These nanoparticles were monodispersed in nonpolar solvent and negatively charged under the existence of aerosol-OT (AOT or sodium di-2-ethylhexylsulfosuccinate). This method was based on the process of electrostatic interaction, in which the LiNbO3 crystal wafers were heated in the presence of decorating colloid solvent. The charged nanoparticles deposited preferentially on the surfaces of those domains with the opposite charges. The delineated patterns corresponded with the polarization property of domain structures and consequently provided a domain contrast image with resolution down to micron scale. This decoration technique is effective, easily operated, nondestructive for sample, noninvasive for human body, and especially, is more suitable for the domain mapping of oxide ferroelectric crystals. In addition, the initial exploration of the model of such decoration process is also presented in this article. [ABSTRACT FROM AUTHOR]

Background: Vitamin D is important for maintaining physiological functions including cognition and its deficiency is associated with the occurrence of cognitive impairment. This study was to explore the association between preoperative vitamin D status and the occurrence of postoperative cognitive dysfunction (POCD) in elderly patients undergoing major surgery.Methods: This was a predefined exploratory sub-analysis of one-centre data from a randomized controlled trial. In all, 123 elderly (≥ 65 years) patients who were scheduled to undergo major cancer surgery were recruited. Serum 25-hydroxyvitamin D concentration was measured before surgery. In total, 59 nonsurgical control subjects with comparable age and education level were also enrolled. A battery of neuropsychological tests was administered the day before and the 7th day after surgery in patients or at the same time interval in control subjects. POCD was diagnosed according to the ISPOCD1 definition.Results: 71.5% (88/123) of elderly patients had vitamin D deficiency (serum 25-hydroxyvitamin D concentration < 12 ng/ml) before surgery; 24.4% (30/123) of them developed cognitive dysfunction at 1 week after surgery. After adjusting for confounding factors, high preoperative serum 25-hydroxyvitamine D concentration was related to a decreased risk of POCD (odds ratio [OR]: 0.829, 95% confidence interval [CI]: 0.708-0.971; P = 0.020), whereas preoperative vitamin D deficiency was associated with an increased risk of POCD (OR: 8.427, 95% CI: 1.595-44.511; P = 0.012).Conclusions: Vitamin D deficiency is prevalent in elderly patients undergoing major cancer surgery and increases the risk of early POCD development. Whether prophylactic vitamin D supplementation can reduce POCD in the elderly deserves further study. [ABSTRACT FROM AUTHOR]

In this letter we report the experimental result on the study of light scattering in a one-dimensional quasiperiodically poled LiTaO3 crystal. The infrared scattering signal in the crystal was upconverted into visible band by sum frequency with incident light, forming a set of coaxial conical second harmonic beam with a quasiperiodic ratio at the radius. The quasi-phase-matching significantly enhanced such a nonlinear interaction. The angular distribution of scattering light in crystal was extracted from the experimental result. This reveals a possible application of quasiperiodic structure on the study of light scattering. [ABSTRACT FROM AUTHOR]

The Nd:YVO4 thin films with a-axis preferred orientation have been grown on SiO2/Si substrates using pulsed laser deposition. Their structural, spectroscopic ellipsometric, and emission characteristics have been systematically studied. The lower ambient oxygen pressure during deposition would lead to better crystallinity in the films. The fluorescence at 1064.8 and 1342 nm in the Nd:YVO4 films was excited with an 808 nm diode laser as pump. The results show that the highly a-axis oriented Nd:YVO4 films grown on Si substrates may have potential applications in actively integrated circuits. [ABSTRACT FROM AUTHOR]

We report a quasi-white-light laser, which was generated by an all-solid-state laser technique. The approach is to use a cascaded optical superlattice in a LiTaO3 crystal to directly frequency double and triple a diode-pumped, Q-switched dual-wavelength Nd:YVO4 laser. Three primary color lights, red at 671 nm, green at 532 nm, and blue at 447 nm, were simultaneously generated in a proper proportion, forming a quasicontinuous, quasi-white-light laser with a maximum output power of 530 mW under a pump power of 18 W. From the result, a more effective quasi-white-light output can be anticipated if the superlattice is fabricated in a stoichiometric LiTaO3 crystal and the double resonant technique is further optimized. [ABSTRACT FROM AUTHOR]

MgO-doped congruent Lithium Niobate (MgO:CLN) is widely used in a variety of nonlinear optical processes, while its Sellmeier equation has only been derived from experiments under 200°C. Here we extend the temperature range for the Sellmeier equation study to as wide as 60 °C to 510 °C. This work is important to extend the operation temperature range of MgO:CLN crystal. [ABSTRACT FROM AUTHOR]

Nonlinear frequency conversion is promising for manipulating photons with orbital angular momentum (OAM). In this letter, we investigate the second harmonic generation (SHG) of light beams carrying fractional OAM. By measuring the OAM components of the generated second harmonic (SH) waves, we find that the integer components of the fundamental beam will interact with each other during the nonlinear optical process; thus, we figure out the law for topological charge transfer in frequency doubling of the fractional OAM state. Theoretical predictions by solving the nonlinear coupled wave equations are consistent with the experimental results. [ABSTRACT FROM AUTHOR]

In this letter, we demonstrate the realization of nonlinear Cherenkov difference-frequency generation (CDFG) exploiting the birefringence property of KTiOPO4 (KTP) crystal. The pump and signal waves were set to be along different polarizations, thus the phase-matching requirement of CDFG, which is, the refractive index of the pump wave should be smaller than that of the signal wave, was fulfilled. The radiation angles and the intensity dependence of the CDFG on the pump wave were measured, which agreed well with the theoretical ones. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate multiple copies of optical orbital angular momentum (OAM) states through quasi-phase-matched (QPM) second-harmonic (SH) generation in a 2D periodically poled LiTaO3 (PPLT) crystal. Since the QPM condition is satisfied by involving different reciprocal vectors in the 2D PPLT crystal, collinear and noncollinear SH beams carrying OAMs of l2 are simultaneously generated by the input fundamental beam with an OAM of l1. The OAM conservation law (i.e., l2 = 2l1) holds well in the experiment, which can tolerate certain phase-mismatch between the interacting waves. Our results provide an efficient way to obtain multiple copies of the wavelength-converted OAM states, which can be used to enhance the capacity in optical communications. [ABSTRACT FROM AUTHOR]

We report a simple, novel subdiffraction method, i.e. diffraction interference induced superfocusing in second-harmonic (SH) Talbot effect, to achieve focusing size of less than λSH/4 (or λpump/8) without involving evanescent waves or subwavelength apertures. By tailoring point spread functions with Fresnel diffraction interference, we observe periodic SH subdiffracted spots over a hundred of micrometers away from the sample. Our demonstration is the first experimental realization of the Toraldo di Francia's proposal pioneered 62 years ago for superresolution imaging. [ABSTRACT FROM AUTHOR]

One of the most fascinating predictions of the theory of general relativity is the effect of gravitational lensing, the bending of light in close proximity to massive stellar objects. Recently, artificial optical materials have been proposed to study the various aspects of curved spacetimes, including light trapping and Hawking radiation. However, the development of experimental 'toy' models that simulate gravitational lensing in curved spacetimes remains a challenge, especially for visible light. Here, by utilizing a microstructured optical waveguide around a microsphere, we propose to mimic curved spacetimes caused by gravity, with high precision. We experimentally demonstrate both far-field gravitational lensing effects and the critical phenomenon in close proximity to the photon sphere of astrophysical objects under hydrostatic equilibrium. The proposed microstructured waveguide can be used as an omnidirectional absorber, with potential light harvesting and microcavity applications. [ABSTRACT FROM AUTHOR]

We report a direct observation of guided-mode interference in polymer-loaded plasmonic waveguides by the technique of leakage radiation microscopy (LRM). Spatial beating patterns of the interferences were clearly characterized with respect to different structural parameters, and the interference properties were analyzed in detail. Besides, the capability of LRM for characterizing the multiple modes was also discussed extensively. Our finding not only offers an efficient technique in analyzing the guided modes and their interference, but also provides a definite guideline in evaluating the validity of LRM and deepens further studies on the dielectric-loaded hybrid waveguide system. [ABSTRACT FROM AUTHOR]

We observe multiple simultaneous cascaded-χ(2) Cˇerenkov conical radiations in radially poled nonlinear photonic crystals. By using two incident fundamental waves ω1 and ω2, a variety of cascaded nonlinear up-conversion processes occur which result in high-frequency Cˇerenkov radiations at 2ωi+ωj(i,j=1,2) exhibiting as multicolor conical beams. Two types of phase-matching geometries with different emission angles are demonstrated for each kind of cascaded-χ(2) Cˇerenkov radiation. The external angle of the Cˇerenkov radiation exhibits strong dependence on the fundamental wavelengths. The experimental results agree well with the theoretical calculations. [ABSTRACT FROM AUTHOR]

In this paper, the plasmon coupling effect between two gold nanospheres on a gold slab is investigated. At plasmon resonance frequencies, electrons on the surface of the slab are absorbed into spheres and contribute to plasmon oscillation. This effect can enhance the local electric field and optical coupling force between the two spheres. [ABSTRACT FROM AUTHOR]

The pathophysiology of post-operative cognitive dysfunction remains unclear and there is no widely accepted animal model that can simulate its occurrence. The purpose of this study was to explore the effects of surgical stress on long-term post-operative memory function in mice of different ages. Healthy C57Bl/6J male mice, of either 4- or 16-month-old, were each randomly divided into three subgroups. (1) Control group: neither anesthesia nor surgery was performed; (2) Anesthesia group: general anesthesia was administrated, surgery was not performed; (3) Surgery group: two-thirds partial hepatectomy was completed in about 15 min under general anesthesia. Morris water maze test was performed after 30 days. In mice of both month-ages, the escape latencies as well as the swimming distances decreased significantly across training days ( P<0.001). In 4-month-old mice, there were no significant differences among three subgroups. In 16-month-old mice, the escape latency was significantly less in the surgery group than in the control group ( P=0.001), and the swimming distance was significantly shorter in the surgery group than in the control and the anesthesia groups ( P=0.001 and 0.047, respectively). In the spatial probe test, time spent in the target quadrant was significantly longer in the surgery group than in the combined control and anesthesia group ( P=0.037). Partial hepatectomy did not produce significant long-term effects on memory function in 4-month-old mice. However, it significantly improved long-term memory function in 16-month-old mice. [ABSTRACT FROM AUTHOR]

This study is to assess the difference between IV-G and IV-S in a large cohort of Chinese patients with lupus nephritis. The detailed data of patients with subclass IV-G and IV-S were retrospectively analyzed. Serum ANCA and anti-C1q antibodies were detected. A total of 172 cases were classified as class IV, including 152 cases with IV-G and 20 cases with IV-S. In IV-S, the level of haemoglobin was significantly higher (P = 0.024), proteinuria was milder (P = 0.003), serum creatinine was lower (P = 0.021), serum C3 was higher (P = 0.045) and the ratio of positive serum anticardiolipin antibodies was higher (P = 0.014). On pathological evaluation, the ratio of glomerular fibrinoid necrosis was significantly higher (P = 0.006) and the score of endocapillary hypercellualrity, interstitial inflammation and total activity indices was significantly lower (P < 0.001, P = 0.01, P = 0.006, respectively) in IV-S. The frequency of serum ANCA was significantly higher in IV-S than that in IV-G (20 vs 4.6%, P = 0.008). The frequencies of anti-C1q IgG1 and IgG3 subclass were significantly higher in IV-G (P = 0.006, P = 0.011, respectively). There are significant differences in clinical and pathological manifestations between IV-S and IV-G lupus nephritis which need further investigation. [ABSTRACT FROM AUTHOR]

The three-color continuous-variable entanglement directly produced by a cascaded nonlinear process in an optical superlattice was investigated theoretically. This cascaded nonlinear process can be realized by using quasi-phase-matching technique in a quasiperiodic superlattice. In the first step, signal- and idle-beams can be generated by a parametric down-conversion. Then, the third beam can be obtained through sum-frequency of idle and pump. The degree of quadrature phase amplitude correlations between the three modes was discussed by a sufficient inseparability criterion with a single inequality for continuous-variable entanglement. [ABSTRACT FROM AUTHOR]

We present an approach to generating a tunable orange laser from 0.601 to 0.604 μm based on a quasi-periodically poled superlattice in LiTaO3 and a Q-switched 1.064 μm Nd:YVO4 laser as pump. The orange laser was generated in a cavity by a parametric process cascaded by a frequency mixing with a maximum output of 310 mW using 15 W pump power. [ABSTRACT FROM AUTHOR]

High-power blue light was generated from a diode-side-pumped Q-switched 1319 nm Nd:YAG laser with a periodically poled, stoichiometric LiTaO3 (PPSLT) crystal. The PPSLT sample used in this experiment consists of two segments in series: the first segment has a period of 14.08 μm for the second harmonic generation (SHG) and the second segment has periods of around 4.6 μm for the generation of blue light by mixing fundamental and SH. An average power of 466 mW of a 440 nm blue light was obtained at the fundamental power of ∼5.4 W with a conversion efficiency of 8.6%. The output power fluctuated by 3% over a half-hour period. This result indicates that our scheme is a practical method to construct a reliable compact blue laser. [ABSTRACT FROM AUTHOR]

High power red light was generated from a periodically-poled stoichiometric LiTaO3 (PPSLT) by single-pass frequency doubling of a diode-side-pumped, Q-switched Nd:YAG laser at 1319 nm. An average power of 2.4 W of the 660 nm red light was obtained at the fundamental power of ∼5.4 W with the conversion efficiency up to 44.4% and with low fluctuation down to 2%. The high efficiency and stability at the red output indicate that it is a practical method to construct a reliable compact red laser. [ABSTRACT FROM AUTHOR]

We experimentally achieved enhanced third harmonic generation (THG) from hole-array in gold film. The surface plasmon polarition excitations, considered as the major contribution to this THG enhancement, are elaborately studied by a spectrum-resolved femto-second laser system. The momentum matching conditions between the fundamental and harmonic waves are well established, giving results of a series of clear THG beam spots with respect to different excitation wavelengths. This efficient THG beaming from the pure metallic structure would considerably broaden the research in the field of nonlinear plasmonics. [ABSTRACT FROM AUTHOR]

A resonance plasmon mode is formed between a gold nanorod and an infinite slab in infrared range, with local electric field enhancement factor over 40. A strong optical attractive force is exerted on the rod by the slab at resonance frequency. Based on Maxwell stress tensor method and numerical simulations, the optical force was calculated to be over 2.0 nN/(mW/μm2). For a fixed incident wavelength, the enhanced optical force is obtained only for the rods with particular length when the diameter is fixed. This strong optical force could be used as a possible selective optical trapping technique in the future. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate a plasmonic assisted Fabry-Perot cavity in a metal/insulator/metal trilayer structure with L-shaped hole arrays inside, which significantly contribute to the mechanism to realize a nearly complete polarization conversion (=0.93) in optical transmissions at near-infrared wavelength. This interesting property is found arising from an overlap of the cavity and plasmonic modes in two orthogonal polarization states. This discovered physics remarkably endows this plasmonic metamaterial with good optical performance and looser fabrication requirement, not only indicating practical applications but also providing fruitful inspirations in future nanophotonic designs. [ABSTRACT FROM AUTHOR]

We numerically investigated the magnetic plasmon resonances in the double-rod and tri-rod structures (DRSs and TRSs) for sensing applications. Like localized surface plasmon modes in nanostructures, the magnetic plasmon resonance wavelengths are sensitive to refractive index changes in the environment medium. The electromagnetic fields near DRSs and TRSs were much more localized in the dielectric surrounding the structures at the resonance wavelengths, which caused the linewidth of magnetic responses narrower. A large figure of merit could be obtained in the magnetic plasmon modes of DRSs and TRSs, which enables the use of the structures as sensing elements with remarkable performance. [ABSTRACT FROM AUTHOR]

We propose and analyze theoretically a double magnetic plasmon resonance nanolaser, in which ytterbium-erbium codoped material is used as the gain medium. Through design of the double magnetic resonance modes, pumping light (980 nm) can be resonantly absorbed and laser light (1550 nm) can be resonantly generated simultaneously. We introduce a set of rate equations combined to describe the operation of the laser and predict the lasing condition. According to our calculations, the disadvantage that pumping light is difficult to be absorbed by a thin slab of gain materials can be overcome. [ABSTRACT FROM AUTHOR]

The magnetic plasmon (MP) modes in a metallic nanosandwich chain with a linearly increasing spacing along the chain has been investigated. Because of the graded coupling between nanosandwiches, the MP gradon with special field localization and large field amplitude can be found in the chain as well as the extended mode, which differs from the case of periodic chain. Using this property, we can precisely control the field in the chain and guide it to different ports at different frequencies, which works as a selective switch and may have potential application in integrated optics. Finally, we give out the underlying physical mechanism to help better understand and apply this graded chain. [ABSTRACT FROM AUTHOR]

The optical bistability and multistability in one-dimensional photonic crystal with the periodic metal-dielectric structure is investigated theoretically. In linear transmission, a structure with N periods will support N-1 resonant modes which correspond to the transmission peaks. Strong localized effect in these resonant modes is obtained. Optical bistability and multistability can be achieved when the incident wavelength is close to a resonance, which can be seen as an effect of the dynamic shifting of the wavelength of the resonant modes. It is found that the threshold for optical bistability in the periodic resonant structure is lower than the nonresonant metal-dielectric structure. [ABSTRACT FROM AUTHOR]

The propagation of microwaves through a chiral metamaterial based on a magnetic dimer is experimentally studied. As proposed by our previous theoretical model, two resonance peaks are obtained in the transmission spectrum; these originate from the hybridization effect of magnetic resonance modes in this system. Optical activity is also observed in the transmission wave. The polarization state dramatically changes around the resonance frequency: the transmitted wave becomes elliptically polarized with its major polarization axis approximately perpendicular to that of the linear incident wave. This coupled magnetic dimer system provides a practical method to optically design tunable active medium and device. [ABSTRACT FROM AUTHOR]

We propose a subwavelength waveguide composed of two parallel nanorod chains. Based on the finite-difference time-domain analysis, we find that the electromagnetic energy can be highly confined in the gaps of nanorod pairs and transported in the gap waveguide through strong magnetic coupling interaction between neighboring nanorod pairs. In a structure with the rod length of 500 nm and the gap size of 100 nm, the energy flow cross section of the propagation mode can be restricted to the size of λ/33×λ/16 at the frequency of 130.0 THz. The corresponding attenuation length of energy propagation reaches 7.2λ. Moreover, these propagation modes exhibit a broad continuous frequency band from zero up to a cutoff frequency ωc∼162.6 THz. [ABSTRACT FROM AUTHOR]

A compact, pulsed, red, green, and blue laser source based on cascaded quasi-phase-matched wavelength conversion in two periodic superlattices set in tandem in a single stoichiometric LiTaO3 crystal and pumped by a laser source at 532 nm is reported. The white light equivalent flux obtained was 80 lm per 1 W input with a green to white light power conversion efficiency of >30%. Unity power conversion is feasible in this monolithic approach. [ABSTRACT FROM AUTHOR]

The authors reported a type of second-harmonic generation in a hexagonally poled LiTaO3 waveguide. The emerged second-harmonic waves exhibited a hexagonal pattern when projected on a screen behind the waveguide. This frequency conversion process was realized by guided-to-radiated mode interaction. Phase matching for this process was automatically achieved by a quasi-phase-matched Cˇerenkov configuration. [ABSTRACT FROM AUTHOR]

We report a large enhancement of third-harmonic generation in the one-dimensional dielectric photonic-crystal-based amorphous nanocavity. The enhancement took place at the frequency of defect mode and was a pure χ(3) nonlinear process. A great increase of third-harmonic intensity up to approximately five orders of magnitude was demonstrated, which was attributed to field localization in the range of nanocavity. [ABSTRACT FROM AUTHOR]

Nd-doped GdVO4(Nd:GdVO4) films with a-axis preferred orientation were fabricated on SiO2/Si substrate by pulsed-laser deposition. Fluorescences at around 1065.0 and 1342.5 nm, corresponding to 4F3/2→4I11/2 and 4F3/2→4I13/2 transitions, respectively, were excited simultaneously with an 808 nm diode laser. Waveguide behaviors in the film were investigated by using the prism coupling technique at the wavelength of 632.8 nm. Both TE and TM mode spectra revealed that favorable light confinements were achieved within the Nd:GdVO4 waveguide layer. Additionally, the optically anisotropic properties of the film were studied in detail. [ABSTRACT FROM AUTHOR]

We study the propagation of an electromagnetic (EM) wave in piezoelectric–piezomagnetic multilayers, in which the incident EM wave excites high frequency acoustic waves and couples strongly with them through piezoelectric and piezomagnetic effects, creating dielectric polariton and magnetic polariton simultaneously. The dispersion abnormality appears at some frequency ranges where simultaneous negative permittivity and permeability can be achieved. Theoretical analysis and numerical simulation proved that this structure forms a kind of “left-handed” material. [ABSTRACT FROM AUTHOR]

Optical reflectance of a two-dimensional (2D) metallodielectric (MD) photonic crystal composed of hexagonal array of close-packed silver-shell polystyrene-core composite particles has been studied at off-normal incidence under both P and S polarizations. A dramatic change in reflectivity behavior of the 2D MD film from a 2D colloidal crystal template and a homogeneous silver film has been observed. The phenomenon of strong reflectance bands of the 2D MD film was explained as a selective coupling of the incident light with surface plasmon of the 2D textured structure via the 2D grating. [ABSTRACT FROM AUTHOR]

An efficient generation of red light in a periodically-poled nearly-stoichiometric LiTaO3 (PPSLT) by extracavity single-pass frequency doubling of a diode-pumped, Q-switched Nd:YVO4 laser at 1342 nm was realized. An average power of 1.4 W of the 671 nm red light is obtained at the fundamental power of ∼2.8 W with the conversion efficiency of 50%. The high conversion efficiency and steady output of red light indicate that the thick PPSLT is a competitive candidate for frequency conversion in order to construct a compact all-solid-state red laser. [ABSTRACT FROM AUTHOR]

We demonstrate simultaneous quasi-continuous wave generation of red, yellow, green and blue coherent radiation based on quadruple quasi-phase matching (QPM) frequency upconversion from a single, aperiodically poled LiTaO[sub 3] (APPLT) crystal with a diode-pumped Nd:YVO[sub 4] dual-wavelength laser oscillating at 1342 and 1064 nm. We designed and prepared an APPLT crystal, which can provide four pertinent reciprocals for simultaneous quadruple QPM processes. Namely, frequency doubling of 1342 nm generates red light at 671 nm, sum-frequency mixing of 1342 nm and 1064 nm produces yellow light at 593 nm, frequency doubling of 1064 nm achieves green light at 532 nm and sum-frequency mixing of 1342 nm and 671 nm obtains blue light at 447 nm. [ABSTRACT FROM AUTHOR]

We demonstrate simultaneously efficient generation of cw red, yellow, and green coherent radiations, ''traffic signal lights,'' by multifrequency conversions from a diode-pumped Nd:YVO[SUB4] dual-wavelength laser with a single-pass aperiodically poled LiTaO[SUB3] . The 1.8 mW red at 671 nm and 0.64 mW green at 532 nm are, respectively, generated by frequency doubling of fundamental waves at 1342 and 1064 nm, and 0.79 mW yellow at 593 nm is produced by sum-frequency mixing of the two fundamental waves, under two fundamental waves of 970 mW at 1342 nm and 940 mW at 1064 nm. [ABSTRACT FROM AUTHOR]

The resonance transmission modes with high-quality factors may generate in a one-dimensional dual-periodic photonic band-gap structure. The frequency, frequency interval, and number of these modes can be tuned as desired by adjusting its structural parameters. In this letter, we report the experimental and theoretical results on dual-periodical TiO[sub2]/SiO[sub2] multilayer films. With perfect)transmission and mode controllability, this structure opens a promising way to fabricate multiwavelength filters for future dense wavelength division application. [ABSTRACT FROM AUTHOR]