arXiv subjects

Ting-Ting Liu

Publications and source records attributed to Ting-Ting Liu.

9 recordsLinked to original sources

arXiv2025

Structured Harmonic Generation via Geometric Phase Enabled Pump Shaping

Nonlinear optics is crucial for shaping the spatial structure of shortwave light and its interactions with matter, but achieving this through simple harmonic generation with a single pump is challenging. This study demonstrates nonlinear spin-orbit conversion using spin-dependent pump shaping via geometric phase, allowing the direct creation of desired structured harmonic waves from a Gaussian pump beam. By using the liquid-crystal flat optical elements fabricated with photoalignment, we experimentally produce higher-order cylindrically vectorial modes in second harmonic fields. We examine the vectorial spatial wavefunctions, their propagation invariance, and nonlinear spin-orbit conversion. Our results provide an efficient method for full structuring nonlinear light in broader harmonic systems, with significant applications in laser micromachining and high-energy physics.

physics.optics↗

arXiv2025

The Mini-SiTian Array: Optical design

Time-domain astronomy is one of the most important areas. Large sky area, deep-field, and short timescale are the priority of time-domain observations. SiTian is an ambitious ground-based project processing all sky optical monitoring, aiming for sky-survey timescale of less than 1 day. It is developed by the Chinese Academy of Sciences, an integrated network of dozens of 1-m-class telescopes deployed worldwide. The Mini-SiTian Telescope Array is carried out for demonstrations on optical design, group scheduling, and software pipeline developments, to overcome the high technical and financial difficulties of SiTian project. One array contains three 300 mm F/3 telescope, with FOV of 5 degrees over 400-1000 nm wavelength range. The Mini-SiTian Telescope Array is now under commissioning in Xinglong Observatory, and a perfect platform for technical research and educational purposes.

astro-ph.IM↗

arXiv2024

Talbot-like pattern evolution in complex structured light from unitary transformation

Astigmatic unitary transformations allow for the adiabatic connections of all feasible states of paraxial Gaussian beams on the same modal sphere, i.e., Hermite-Laguerre-Gaussian (HLG) modes. Here, we present a comprehensive investigation into the unitary modal evolution of complex structured Gaussian beams, comprised by HLG modes from disparate modal spheres, via astigmatic transformation. The non-synchronized higher-order geometric phases in cyclic transformations originates a Talbot-effect-like modal evolution in the superposition state of these HLG modes, resulting in pattern variations and revivals in transformations with specific geodesic loops. Using Ince-Gaussian modes as an illustrative example, we systematically analyze and experimentally corroborate the beamforming mechanism behind the pattern evolution. Our results outline a generic modal conversion theory of structured Gaussian beams via astigmatic unitary transformation, offering a new approach for shaping spatial modal structure. These findings may inspire a wide variety of applications based on structured light.

physics.optics↗

arXiv2023

Partial wave effects in the heavy quarkonium radiative electromagnetic decays

In a previous paper \cite{Bc}, it was pointed out that the wave functions of all particles are not pure waves, besides the main partial waves, they all contain {other partial waves}. It is very interesting to know what role these different partial waves play in particle transitions. Therefore, by using the Bethe-Salpeter equation method, we study the radiative electromagnetic decays $ψ\rightarrowγχ_{_{cJ}}$ and $Υ\rightarrowγχ_{_{bJ}}$ ($J=0,1,2$). We find that for the $S$ and $P$ wave dominated states, like the $ψ(2S)$, $Υ(2S)$, $χ_{_{cJ}}(1P)$, and $χ_{_{bJ}}(1P)$ etc., the dominant $S$ and $P$ waves provide main and nonrelativistic contrition to the decays; other partial waves mainly contribute to the relativistic correction. For the states like the $ψ(1D)$, $Υ(2D)$, $χ_{c2}(1F)$, and $χ_{b2}(1F)$ etc., they are the $S-P-D$ mixing state dominated by $D$ wave or the $P-D-F$ mixing state dominated by $F$ wave. Large decay widths are found in the transitions $ψ(2D)\to χ_{c2}(1F)$, $Υ(1D)\to χ_{bJ}(1P)$, and $Υ(2D)\to χ_{bJ}(2P)$ etc., which may be helpful to study the missing states $χ_{c2}(1F)$, $Υ(1D)$, and $Υ(2D)$.

hep-ph↗

arXiv2023

Decay properties of $D_{s0}^*(2317)^+$ as a conventional $c\bar s$ meson

Taking $D_{s0}^{*}(2317)^{+ }$ as a conventional $c\bar s$ meson, we calculate its dominant strong and electromagnetic decays in the framework of the Bethe-Salpeter method. Our results are $Γ(D_{s0}^{*+}\to D_s^+π^0) = 7.83^{+1.97}_{-1.55}$ keV and $Γ(D_{s0}^{*+}\to D_s^{*+}γ) = 2.55^{+0.37}_{-0.45}$ keV. The contributions of the different partial waves from the initial and final state wave functions to the decay width are also calculated, and we find that the relativistic corrections in both decay processes are very large.

hep-ph↗

arXiv2022

The partial waves of $B^{*}_{2}(5747)$ and their contributions in strong decays

By adopting the relativistic Bethe-Salpeter method, the OZI allowed strong decays of the $2^+$ state $B^{*}_{2}(5747)^{0}$ are studied, emphasis is paid to the relativistic corrections. We first study the partial waves in the wave functions used, find that there are $P$, $D$ and $F$ partial waves in $B^{*}_{2}(5747)^{0}$ meson, and the ratios $P:D:F=1:0.421:0.051$. We also find $S:P:D=1:0.354:0.046$ for $B^*$, and $S:P=1:0.343$ for $B$ meson. The large components of the $D$ wave in $B^{*}_{2}(5747)^{0}$ and $P$ wave in $B^{(*)}$ means that large relativistic effects existing in these states. Second, we calculate the strong decays, the obtained total decay width $Γ(B^{*}_{2}(5747)^{0})=25.9$ MeV and the branching fraction $Γ(B^{*}_{2}(5747)^{0} \to B^{*}π)$ / $Γ(B^{*}_{2}(5747)^{0} \to Bπ)=0.96$ are consistent well with experimental data. Third, we study the contributions of different partial waves in the initial and final wave functions, find that the relativistic effects are about $15\%$ and $11\%$ for $B^{*}_{2}(5747)^{0} \to Bπ$ and $B^{*}_{2}(5747)^{0} \to B^{*}π$, respectively, which are much smaller than our expected, showing that the relativistic corrections are cancelled to each other in these decays.

hep-ph↗

arXiv2017

Observation of topological edge states of sound at a momentum away from the high-symmetry point

Topologically protected one-way transportation of sound, mimicking the topological properties of the condensed matter, has received greatly attentions. Thus far, the topological phases and the topological edge states of sound are yielded in the vicinity of the Dirac cones fixed at the high symmetric points of the Brillouin zone. Here, we present a new type of the phononic topological insulator in the square lattice with position-variational Dirac cones along the high symmetric lines. The emergence of such Dirac cones, characterized by the vortex structure in a momentum space, is attributed to the unavoidable band crossing protected by the mirror symmetry. By rotating the square columns, these Dirac points are lifted and a complete band gap is induced because of the mirror-symmetry-breaking. Along the topological domain wall between the phononic crystals (PhCs) with the distinct topological phases stemming from the mirror symmetry inversion, we obtain a topological edge state for the neutral scalar sound which is absence of the intrinsic polarization and is uncoupled from an external field. Within a wide rotational range of the square column, the topological edge state in our PhCs evolves from a gapless one into a gapped one with a robust edge transport against cavities and disorders. Our excellent results are promising for the exploration of the new topological phenomena in the PhCs beyond the hexagonal lattices. Furthermore, the flexibility of the rotational square columns provides an interesting platform for the design of tunable topological acoustic devices.

cond-mat.mtrl-sci↗

arXiv2017

Steerable sound transport in a 3D acoustic network

Quasi-lossless and asymmetric sound transports, which are exceedingly desirable in various modern physical systems, are almost based on nonlinear or angular-momentum biasing effects with extremely high power levels and complex modulation schemes. A practical route for the steerable sound transport along any arbitrary acoustic pathway, especially in a 3D acoustic network, could revolutionize the sound power flow and the sound communication. Here, we design an acoustic device consisting of a regular-tetrahedral cavity with four cylindrical waveguides. A smaller regular-tetrahedral solid in this cavity is eccentrically emplaced to break its spatial symmetry. The numerical and experimental results show that the sound power flow can unimpededly transport between two waveguides away from the eccentric solid within a wide frequency range. Furthermore, in the vicinity of eigenmode, the sound waves from various waveguides can transport to different waveguides, respectively along the compressed and broadened pathways without mutually interference. Endowed with these quasi-lossless and asymmetric transport characteristics, we construct a 3D acoustic network, in which the sound power flow can flexibly propagate along arbitrary sound pathways defined by our acoustic devices with eccentrically-emplaced regular-tetrahedral solids.

physics.class-ph↗

arXiv2017

Topological phononic insulator with robustly pseudospin-dependent transport

Topological phononic states, facilitating acoustic unique transports immunizing to defects and disorders, have significantly revolutionized our scientific cognition of acoustic wave systems. Up to now, the theoretical and experimental demonstrations of topologically protected one-way transports with pseudospin states in a phononic crystal beyond the graphene lattice with C6v symmetry are still unexploited. Furthermore, the tunable topological states, in form of robust reconfigurable acoustic pathways, have been evaded in the topological phononic insulators. Here, we realize a topological phase transition in the double Dirac degenerate cone of rotatable triangular phononic crystals with C3v symmetry, by introducing the zone folding mechanism. Along a topological domain wall between two portions of phononic crystals with distinct topological phases, we experimentally observe the quantum spin Hall (QSH) effect for sound, characterized by the robust pseudospin-dependent one-way edge model. As the triangular phononic crystals can freely rotate, we straightforward reconfigure an arbitrary contour defined by the topological domain wall along which the acoustic waves can unimpededly transport. Our research develops a new route for the exploration of the topological phenomena in experiments and provides an excellent framework for freely steering the acoustic immune-backscattering propagation within topological phononic structures.

cond-mat.mtrl-sci↗