Innovative design to achieve a multi-band electromagnetic wave stealth.

Metamaterials have opened up a new field of electromagnetic wave stealth that can achieve cross-band electromagnetic wave stealth through high electromagnetic wave absorption and low infrared emission. However, traditional cross-band stealth metamaterials make covering the terahertz band challenging and have certain design flaws. This Letter introduces an innovative cross-band electromagnetic wave stealth metasurface design that can achieve cross-band stealth in the infrared, microwave, and THz bands.

Multifunctional graphene metamaterials based on polarization-insensitive plasmon-induced transparency.

In this paper, a 4L-shaped graphene patterned polarization-insensitive plasmon-induced transparency (PIT) metamaterial structure is proposed. The photoelectric switch based on this structure supports a variety of light sources, such as linearly polarized light with different polarization directions, left rotation circularly polarized light (LCP) and right rotation circularly polarized light (RCP). And the switch has excellent performance in the case of different light sources, the amplitude modulation is as high as 99.

Doppler Lidar with High Sensitivity and Large Dynamic Range for Atmospheric Wind Measurement.

Doppler wind Lidar is an important method for atmospheric wind measurement. The Doppler frequency shift of backscattering spectrum due to the wind is detected from the transmissions of frequency discrimination. High sensitivity and large dynamic range measurement is difficult for atmospheric wind measurement because of the limitationof frequency discriminator characteristic.

Broadband perfect light trapping in the thinnest monolayer graphene-MoS2 photovoltaic cell: the new application of spectrum-splitting structure.

The light absorption of a monolayer graphene-molybdenum disulfide photovoltaic (GM-PV) cell in a wedge-shaped microcavity with a spectrum-splitting structure is investigated theoretically. The GM-PV cell, which is three times thinner than the traditional photovoltaic cell, exhibits up to 98% light absorptance in a wide wavelength range. This rate exceeds the fundamental limit of nanophotonic light trapping in solar cells.

[Research on Modeling Method for Chlorophyll Content Fine Measurement Based on Neural Network].

Aiming at SPAD values of living plant leaf chlorophyll content affected easily by the blade thickness, water content, etc, a fine retrieval method of chlorophyll content based on multiple parameters of neural network model is presented. The SPAD values and water index (WI) of leaves were obtained by the leaf transmittance under the irradiation of light central wavelength in 650 nm, 940 nm, 1450 nm respectively. Meanwhile, the corresponding blade thickness is got by micrometer and the chlorophyll content is measured by spectrophotometric method.

Tunable THz absorption in graphene-based heterostructures.

We investigate THz absorption properties of graphene-based heterostructures by using characteristics matrix method based on conductivity. We demonstrate that the proposed structure can lead to perfect THz absorption because of strong photon localization in the defect layer of the heterostructure. The THz absorption may be tuned continuously from 0 to 100% by controlling the chemical potential through a gate voltage.

Perfect light trapping in nanoscale thickness semiconductor films with a resonant back reflector and spectrum-splitting structures.

The optical absorption of nanoscale thickness semiconductor films on top of light-trapping structures based on optical interference effects combined with spectrum-splitting structures is theoretically investigated. Nearly perfect absorption over a broad spectrum range can be achieved in <100 nm thick films on top of a one-dimensional photonic crystal or metal films. This phenomenon can be attributed to interference induced photonic localization, which enhances the absorption and reduces the reflection of the films.

[Determination of sodium by near infrared spectroscopy].

The research on near infrared spectroscopy of sodium in biological and medicine is significant. Sodion is the main component of electrolytes in human blood and electrolytes help maintain the body's acid-base balance. In the present paper the concentration of sodium was determined with the use of NIR spectra.

Proposal for the momentum-resolved and time-resolved optical measurement of the current distribution in semiconductors.

The two-color optical coherence absorption spectrum (QUIC-AB) of semiconductors in the presence of a charge current is investigated. We find that the QUIC-AB depends strongly not only on the amplitude of the electron current but also on the direction of the electron current. Thus, the amplitude and the angular distribution of current in semiconductors can be detected directly in real time with the QUIC-AB.

[The Mie scattering lidar return signal denoising research based on EMD-DISPO].

Lidar echo signal is a typical non-steady-state, non-stationary signal, and difficult to be dealt with by the traditional filtering methods. As a new signal processing theory proposed in recent years, empirical mode decomposition method can adaptively divide the lidar echo signal into different intrinsic mode function (IMF) components according to different time scale, and noise mainly concentrates in the high-frequency component. However, when filtered with simply removing high frequency component, the useful signal will be possibly reduced.

N-(2-Chloro-pyrimidin-4-yl)-2-methyl-2H-indazol-6-amine methanol monosolvate.

In the title compound, C(12)H(10)ClN(5)·CH(3)OH, the indazole ring system and the pyrimidine ring make a dihedral angle of 23.86 (4)°. In the crystal, the components are linked by N-H⋯O and O-H⋯N hydrogen bonds into chains propagated in [010].

Omnidirectional bandgaps in Fibonacci quasicrystals containing single-negative materials.

The band structure and bandgaps of one-dimensional Fibonacci quasicrystals composed of epsilon-negative materials and mu-negative materials are studied. We show that an omnidirectional bandgap (OBG) exists in the Fibonacci structure. In contrast to the Bragg gaps, such an OBG is insensitive to the incident angle and the polarization of light, and the width and location of the OBG cease to change with increasing Fibonacci order, but vary with the thickness ratio of both components, and the OBG closes when the thickness ratio is equal to the golden ratio.

[Lidar observations of atmospheric aerosol optical properties over Yinchuan area].

A compact Mie scattering lidar system has been developed to measure the optical properties and temporal-spatial distribution of atmospheric aerosol particles and some continuous experiments were carried out over Yinchuan area (38 degrees 29'N, 106 degrees 06'E) from 1 to 10 April in 2009 for the first time. The laser located at wavelength of 532 nm was selected as the light source and the Fernald method was used to retrieve the extinction coefficient. The aerosol extinction coefficient profiles and temporal-spatial variation properties of aerosol relative density were obtained and analyzed within the whole day at one hour interval, and also an obvious sand-dust-weather process over Yinchuan area was observed and analyzed.