Deep learning based coherent diffraction imaging of dynamic scattering media.

The ptychographic iterative engine (PIE) is a lensless coherent diffraction imaging algorithm known for its simplicity, easy to use, scalability, and fast convergence. However, practical applications often encounter interference in imaging results caused by non-static scattering media, such as dense fog, seawater target detection and medical biology diagnosis. To address this challenge, we propose a novel approach using computational deep learning for dynamic scattering medium image reconstruction, enabling lens-free coherent diffraction imaging through dynamic scattering media.

Determination of quantity and volume of Carya cathayensis Sarg by line laser scanning combined with the point cloud fusion algorithm.

Optical 3D measurement technology plays a vital role in diverse industries, particularly with the advancements in line laser scanning 3D imaging. In this paper, we propose a line laser scanning-based investigation for detecting Carya cathayensis Sarg. The Carya cathayensis Sarg specimens are scanned using a line laser to achieve three-dimensional reconstruction, enabling the calculation of their volume and quantity based on the acquired point cloud map.

Investigation of the effect of chirped factors on the interference enhancement effect of an Airyprime beam propagating in free space.

The first-order and the second-order chirped factors are imposed on the Airyprime beam, and the analytical expression of the chirped Airyprime beam propagating in free space is derived. The phenomenon that the peak light intensity on observation plane other than initial plane is greater than that on initial plane is defined as the interference enhancement effect, which is caused by the coherent superposition of the chirped Airyprime and the chirped Airy-related modes. The effects of the first-order and the second-order chirped factors on the interference enhancement effect are theoretically investigated, respectively.

Design of autofocusing beams based on accelerating beams.

Autofocusing Airy-like beams have been designed based on the self-accelerating beams along arbitrary polynomial paths. The evolutions of the autofocusing beam in free space and turbulent atmosphere have been studied. Results show that the energy concentration of the autofocusing beam near the focal plane has a close relationship with its accelerating trajectory.

Generating a Bessel-Gaussian beam for the application in optical engineering.

Bessel beam is the important member of the family of non-diffracting beams and has many novel properties which can be used in many areas. However, the source of Bessel beam generated by the existing methods can be used only in a short distance due to its low power. In this paper, based on the coherent combining technology, we have proposed a method which can be used to generate a high-power Bessel beam.

Observation of the asymmetric Bessel beams with arbitrary orientation using a digital micromirror device.

Recently, V. V. Kotlyar et al.

[Theory study on glycine linear oligopeptide vibrational spectrum frequency shift].

By using the density functional theory, glycine linear oligopeptide of different lengths was geometrically optimized on the 6-31G (d) basis set level, their growth processes were simulated, and the average binding energy and vibration frequency were calculated with geometry. The results showed that the average binding energies tend to change in a regular pattern and stabilize with the number of residues increasing; With the oligopeptide chain bond length analysis it was found that the chain to the radial direction there is a opposite trend for chain and radial direction, which is anisotropic. It was found by the IR spectrum analysis that red shifts and blue shifts occur respectively when the same group of peptide bond vibrate, which is anisotropic; These phenomena originate from that quasi one-dimensional nanostructures lead to the anisotropy of the bond length; the induced effects, coupling effects and hydrogen bonding etc.

Beam wander of an Airy beam with a spiral phase.

Beam wander of an Airy beam with a spiral phase in turbulence is investigated. Using the Wigner distribution function, analytical expressions for the second-order moments and second central moments of an Airy beam with a spiral phase in turbulence are derived. A general expression of the beam wander for an Airy beam with a spiral phase is obtained.

Quantitative description of the self-healing ability of a beam.

Quantitative description of the self-healing ability of a beam is very important for studying or comparing the self-healing ability of different beams. As describing the similarity by using the angle of two infinite-dimensional complex vectors in Hilbert space, the angle of two intensity profiles is proposed to quantitatively describe the self-healing ability of different beams. As a special case, quantitative description of the self-healing ability of a Bessel-Gaussian beam is studied.

Propagation of an Airy beam with a spiral phase.

The propagation of an Airy beam with a spiral phase is studied. The centroid position and spread of the beam are investigated analytically for different topological charges. Study shows that the centroid position of the Airy beam with a spiral phase keeps moving during propagation.

Propagation of a partially coherent hollow vortex Gaussian beam through a paraxial ABCD optical system in turbulent atmosphere.

The propagation of a partially coherent hollow vortex Gaussian beam through a paraxial ABCD optical system in turbulent atmosphere has been investigated. The analytical expressions for the average intensity and the degree of the polarization of a partially coherent hollow vortex Gaussian beam through a paraxial ABCD optical system are derived in turbulent atmosphere, respectively. The average intensity distribution and the degree of the polarization of a partially coherent hollow vortex Gaussian beam in turbulent atmosphere are numerically demonstrated.

Propagation of Airy beams in uniaxial crystals orthogonal to the optical axis.

Analytical propagation expression of an Airy beam in uniaxial crystals orthogonal to the optical axis is derived. The ballistic dynamics of an Airy beam in uniaxial crystals is also investigated. The Airy beam propagating in uniaxial crystals orthogonal to the optical axis mainly depends on the ratio of the extraordinary refractive index to the ordinary refractive index.

Propagation of Gaussian-Schell beam in turbulent atmosphere of three-layer altitude model.

We propose a method that is used to derive the moment radius of intensity distribution in a turbulent atmosphere. From this study, we have found that the second moment radius is affected only by the first-order expansion coefficient of the wave structure function. If our attention is directed to a higher moment radius, a higher order approximation of the expansion needs to be used.

Evolution of an Airy beam in turbulence.

The evolution of Airy beam intensity distribution in turbulence is examined. Results show that the centroid position and skewness of an Airy beam are independent on turbulence. When the exponential truncation factor is small, an Airy beam has a long tail on the left side.

Arbitrary moments of elliptical Gaussian-Schell beam in turbulent atmosphere.

Arbitrary moments of elliptical Gaussian-Schell beams in turbulent atmosphere is studied. An analytical formula for arbitrary moments of elliptical Gaussian-Schell beams in turbulent atmosphere is derived. As an example, the kurtosis parameter for elliptical Gaussian-Schell beams in turbulent atmosphere is investigated in detail.

Simultaneous displacement and angular drift measurement based on defocus grating.

We propose and demonstrate a displacement and angular drift simultaneous measurement technique based on a defocus grating. The displacement and angular drift of the incident beam can be detected by monitoring the movements of +/-1 diffraction order spots of the defocus grating. The relationship between drift of the incident beam and movements of +/-1 diffraction order spots is studied in detail.

Average intensity and spreading of a Lorentz-Gauss beam in turbulent atmosphere.

The propagation of a Lorentz-Gauss beam in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and the Hermite-Gaussian expansion of a Lorentz function, analytical formulae for the average intensity and the effective beam size of a Lorentz-Gauss beam are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a Lorentz-Gauss beam in turbulent atmosphere are numerically demonstrated.

Comparison between quadratic approximation and delta expansion in studying the spreading of multi-Gaussian beams in turbulent atmosphere.

Based on quadratic approximation and delta expansion in the first order, the analytical expressions for multi-Gaussian beams in a turbulent atmosphere have been derived. By comparing the two approaches with numerical calculations, the relative errors of average intensity are investigated. As special cases, the relative errors for Gaussian beams, flattened Gaussian beams, and annular beams are investigated.

Propagation of a partially coherent cosine-Gaussian beam through an ABCD optical system in turbulent atmosphere.

The propagation of a partially coherent cosine-Gaussian beam through a paraxial ABCD optical system in turbulent atmosphere is investigated. Analytical expression for the average intensity in the output plane is derived. The presented formula only covers optical systems without inherent apertures, where ABCD are all real-valued.

Propagation of a general multi-Gaussian beam in turbulent atmosphere in a slant path.

The propagation of a multi-Gaussian beam in turbulent atmosphere in a slant path is studied. The analytical expression for the average intensity of a general multi-Gaussian beam is derived. As special cases the average intensities of a two- and a four-Gaussian beam are investigated and numerically calculated.

Propagation of a cosh-Gaussian beam through an optical system in turbulent atmosphere.

The propagation of a cosh-Gaussian beam through an arbitrary ABCD optical system in turbulent atmosphere has been investigated. The analytical expressions for the average intensity at any receiver plane are obtained. As an elementary example, the average intensity and its radius at the image plane of a cosh-Gaussian beam through a thin lens are studied.

Power coupling of a two-Cassegrain-telescopes system in turbulent atmosphere in a slant path.

The characteristics of dark hollow beams passing through a two-Cassegrain-telescopes system in turbulent atmosphere in a slant path have been investigated. The distribution of the average intensity at the receiver telescope and the efficiency of power coupling with respect to propagation distance with different parameters are derived and numerically calculated. These studies illuminate that the power of the dark hollow beams is concentrated on a narrow annular aperture at the source plane and its power coupling with a transmitter Cassegrain telescope can remain quite high.