The timely and accurate detection of unidentified drones is vital for public safety. However, the unique characteristics in complex environments varied postures they may adopt during approach present significant challenges. Additionally, deep learning algorithms often require large models substantial computational resources, limiting their use on low-capacity platforms. To address these challenges, we propose LAMS-YOLO, a lightweight drone method based linear attention mechanisms adaptive...

Introduction The ecological and economic impacts of forest pests have intensified, particularly in remote areas. Traditional pest detection methods are often inefficient inaccurate complex environments, posing significant challenges for effective management. Enhancing the efficiency accuracy under resource-limited conditions has thus become a critical issue. This study aims to address these by proposing an improved lightweight forestry algorithm, RSD-YOLOv8, based on YOLOv8. Methods To...

Abstract We experimentally demonstrate an electrically triggered terahertz (THz) dual-band tunable band-pass filter based on Si 3 N 4 –VO 2 –Si sandwich-structured hybrid metamaterials. The insulator–metal phase transition of VO film is induced by the Joule thermal effect top metal layer. finite-integration-time-domain (FITD) method and finite element (FEM) are used for numerical simulations. sample fabricated using a surface micromachining process, characterized THz time-domain-spectrometer...

A novel technique for focal-length measurements with a circular Dammann grating is presented. In the back focal plane of lens under test, one-order limited aperture will produce double-humped radial rings. The separation between two lobes varies displacement observed from lens. By searching position at which minimal, point can be located and hence length determined. Experimental results demonstrated that this method efficient used effectively quick check length.

A novel circular Dammann grating is proposed to generate uniform-intensity impulse rings corresponding different diffraction orders in the far field. The intensities of are determined by coefficients sine series decomposition function. definition efficiency and uniformity for this device described. Numerical solutions binary phase gratings presented. three-order π depth fabricated an e-beam direct writing technique experimentally demonstrated.

The hyperspectral full polarization imaging system (HFPIS) based on spatial modulation and liquid crystal tunable filter (LCTF) can modulate the information of target into interferogram by means interference imaging. It has advantage rapid from target, good real time practicality. Through spectroscopic mode a Savart prism, corresponding optical path are designed, including beam expander, modulator, LCTF, focusing system, sensor. This extract different demodulate it so as to obtain image....

Optical microresonators confine light to small volumes through resonant circulation. Herein, whispering gallery mode (WGM) have high Q factors among these microresonators, which significant research value in the fields of fundamental physics and optoelectronic devices. However, maintaining a very surface finish on side microresonator is necessary, as keeping coupling distance tens nanometers between waveguide. Thus, this makes fabrication, coupling, packaging difficult seriously hinders...

A digital speckle shearing interferometer is developed using a dynamic binary phase grating realized by an electrically addressed, twisted nematic liquid-crystal spatial light modulator as the element. The standard phase-shifting algorithm can be easily achieved changing pattern displayed on modulator. method has number of advantages including variable sensitivity, no moving part, and requirement for calibration value shift. error due to unexpected diffraction order also discussed.

The nonlinear effects in optical resonators give a promise for the generation of new laser sources. Here, whispering gallery mode(WGM) micro-rod resonator is fabricated and mechanism transmission between Kerr comb to Raman investigated by experimental results amended Lugiato-Lefever equation(LLE) model. We show that, numerically experimentally, WGM resonator-based frequency can be selectively accessed from state Kerr-Raman via pump detuning controlling. When initially set at red detuning,...

A new non-imaging angle measurement method based on an axicon is proposed in this paper. This uses that can form a complex light spot with clear edge and rich feature information after total internal reflection refraction the sloped face compared convergent lenses, which only blurry spot. According to high sensitivity of beam transformation incident angle, images obvious variation be easily obtained achieve accuracy. The meet application requirements multiple ranges, structure simple...

A microfocus X-ray grating interferometer (MFXGI) is proposed to measure the profile of wavefront and slope error optical elements. This device consists a phase G 1 modulate incoming an absorption 2 as transmission mask for position-sensitive detector. The distortions caused by deformable mirror were analyzed under operating conditions in situ investigation MFXGI can obtain direct reflected beams one recorded image at same time through source. beam be used calculate parameter errors...

The number of phase levels a Talbot array illuminator is an important factor in the estimation practical fabrication complexity and cost. We show that (L) has simple relationship to prime number. When there alternative π-phase modulation output array, relations are similar.

In this paper, we present an interferometric method to measure the shape of X-ray wavefront and slope error optical elements using microfocus x-ray source. According fractional Talbot effect, built grating interferometer for characterization at working wavelength. The consists a phase as beam splitter absorption transmission mask detector. however, determination relation between system parameters sensitivity, which is influenced by many in system, crucial optimization setup. It very...

A metrology method of x-ray optical elements based on an electromagnetic phase stepping grating interferometer with high slope accuracy is presented in this study. The device consists tube, a G1 for modulating the incoming wavefront, and absorption G2 as transmission mask to produce broader moiré pattern camera. focal spot microfocus source shifted by magnetic field from solenoid coil. Electromagnetic analysis used obtain pixel-wise map wavefront distortion replace traditional precision...

A novel shearing interferometer is developed using a dynamic grating realized by twisted nematic liquid-crystal spatial light modulator as the element. standard phase shifting algorithm can be easily achieved changing pattern displayed on modulator. with no moving part and requirement for calibration of value shift was therefore achieved.

Pulse-width of ultrashort laser is a very important parameter for the wide applications pulse. Various methods have been proposed to measure pulse-width, such as second harmonic generation method, third method and frequency resolved optical gating method. Despite benefits they hold, share vital drawback: all employ nonlinear effects pulse, which means that input power must be large enough generate effect, central wavelength pulse correspond sensitivity range crystal. In this paper we present...

Optical microresonators confine light to small volumes through resonant circulation. Herein, the whispering gallery mode (WGM) have high Q factors among these microresonators, which significant research value in fields of fundamental physics and optoelectronic devices. However, maintaining a very surface finish on side microresonator is necessary, keeping coupling distance tens nanometers between waveguide. Thus, this makes fabrication, coupling, packaging difficult, seriously hinders...

A novel circular Dammann grating is proposed to generate uniform-intensity impulse rings corresponding different diffraction orders in the far field. Experimental demonstration and some applications are also presented.

A novel circular Dammann grating is proposed to generate uniform-intensity impulse rings corresponding different diffraction orders in the far field. Experimental demonstration and some applications are also presented.

Abstract A π‐phase‐modulated Talbot illuminator means that there is a half‐period π phase modulation in the output array. We will show that, by using rule of regularly rearranged neighboring‐phase difference, simple equations can be derived to describe pure‐phase distributions and pulse‐density increased phenomena illuminator. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 49–52, 2001.