Light carrying orbital angular momentum (OAM) holds unique properties and boosts myriad applications in diverse fields. However, the generation of an ultrafast wave packet numerous vortices with various transverse OAM modes, i.e., vortex string, remains challenging, corresponding detection method is lacking. Here, we demonstrate that a string 28 spatiotemporal optical (STOVs) customizable topological charge (TC) arrangements can be generated one packet. The diffraction rules STOV strings are...

The spatiotemporal optical vortex (STOV) is unique, owing to its phase singularity in the space–time domain, and it can carry transverse orbital angular momentum (OAM). Diffraction a fundamental wave phenomenon that well known for conventional light; however, studies on diffraction of light with OAM are limited. Furthermore, methods enable fast detection STOVs lacking. Here, we theoretically experimentally study behaviors STOVs, which different from those light. patterns STOV pulses...

Fabrication of periodic transient-density structures in a gas jet with boundary scale length approaching 10μm was demonstrated. This achieved by passing an ultrashort high-intensity laser pulse through patterned mask and imaging the onto target plane. Gas/plasma density at laser-irradiated regions drops as result hydrodynamic expansion following ionization heating pulse. The fabrication gas/plasma such scheme is essential step development plasma photonic devices for applications high-field physics.

We report continuous-wave laser operation at 698 nm in Pr3+-doped LiYF4 crystal using an InGaN diode emitting 444 with a maximum output power of 760 mW. By suppressing the oscillation 640 and 721 nm, 156 mW was obtained single transverse mode slope efficiency as high 48.7%. The beam quality factors M2 x y directions were measured to be 1.4 1.2, respectively.

Spatiotemporal optical vortex (STOV) light is a new type of with transverse orbital angular momentum (OAM) which different from conventional spatial light. Understanding the properties STOV are meaningful before applied. We present theoretical study on generation and propagation spatiotemporal vortices step by based diffraction theory. The output pulses topological charges generated using 4 f pulse shaper in both near-field far-field analyzed. Using spiral phase mask, intensity profiles...

Spatiotemporal optical vortex (STOV) carrying transverse orbital angular momentum (OAM) enriches the family of beams and exhibit unique properties. Typically, a high-order STOV with an intensity null degrades into multiple first-order STOVs embedded within single wave packet during propagation, phenomenon known as time diffraction or mode degradation. However, this degradation limits applicability in specialized fields. Therefore, generation degradation-suppressed (MDS-STOVs) is significant...

Isotope detection is crucial for geological research, medical diagnostics, industrial production, and environmental monitoring. Various spectroscopic techniques are continually emerging isotopic identification accurate measurement. Herein, coherent Raman scattering (CRS) spectroscopy developed the quantitative of carbon dioxide isotopes, in which N2+ air lasing coherently created interaction region used as probe. Benefiting from narrow spectral width lasing, peaks 12CO2 13CO2 can be well...

We present a diode-pumped Pr: LiYF4 (Pr:YLF) laser at 695.8 nm by suppressing the higher gain transitions near 640, 670, 698, and 721 nm. With an InGaN diode as pump source, output power of centered in σ polarization was up to 51 mW, corresponding slope efficiency 12.6% threshold 229 mW with respect absorbed power. To best our knowledge, this is first Pr:YLF emitting polarization.

We investigate the dependence of ${\mathrm{N}}_{2}{}^{+}$ lasing radiation on polarization ellipticity pump laser with 900- and 980-nm wavelengths. Our results show that 391-nm is stronger elliptically polarized in 900-nm pumping case, while signal decays monotonically increasing case. In contrast, strongest 428-nm appears linear for both cases. The theoretical simulations reproduce key observations reveal physical origin underlying ellipticity-dependent behaviors sensitivity photoexcitation...

Tunneling ionization, a fascinating quantum phenomenon, has played the key role in development of attosecond physics. Upon absorption few tens photons, tunneling ionization creates ions different excited states and even enables formation population inversion between ionic states. However, underlying physics is still being debated. Here, we demonstrate significant enhancement efficiency multiphoton excitation when neutral molecules resonant coexist strong laser fields. It facilitates dramatic...

Abstract Vortex air lasing opens exciting perspectives for remote generation, amplification, and control of vortex beams in ambient air. By combining the advantages beams, it holds great potential some specific applications such as standoff detection chiral molecules rotating objects. However, remains challenging to produce high‐order flexibly its orbital angular momentum, hindered by inhomogeneous distribution instability laser‐induced plasma. Herein, with a tunable order from first up...

We report a continuous-wave ultraviolet laser at 349 nm obtained by intracavity frequency doubling of diode-pumped Pr <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> -doped LiYF <sub xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> laser. Power scaling lasers 698-nm fundamental wavelength was realized using an InGaN diode with maximum output power 850 mW and 5-mm-long 0.5 a.t. % crystal. The 698 215 mW. With beta barium borate crystal...

Novel multicolor concentric annular ultrafast vector beams (MUCAU-VB) are firstly generated simply by using cascaded four-wave mixing (CFWM) in a glass plate pumped two intense femtosecond pulses. A proof-of-principle experiment shows that up to 10 frequency up-conversion radially polarized sidebands obtained simultaneously based on CFWM process, where the spectra range of first 7 order extending from 545 nm 725 nm. The results prove polarization transfer property pump beam signal even CFWM,...

Increasing any degree of freedom vortex light beam can broaden the application area this special beam. Here, up to nine multicolor concentric ultrafast beams (MUCU-VBs) with controllable orbital angular momentum (OAM) are generated simultaneously using cascaded four-wave mixing in an yttrium aluminum garnet plate. The topological charges (TCs) MUCU-VBs by changing TCs two input pump beams. be manipulated temporal, spatial, and spectral domains OAM state, which will wide applications, such as...

Thermometric techniques with high accuracy, fast response speed and ease of implementation are desirable for the study dynamic combustion environments, transient reacting flows, non-equilibrium plasmas. Herein, single-shot single-beam coherent Raman scattering (SS-CRS) thermometry is developed, first time to our knowledge, by using air lasing as a probe. It's proved that air-lasing-assisted CRS signal has signal-to-noise ratio enabling measurements at 1 kHz repetition rate. The SS-CRS...

A single-shot fourth-order autocorrelator based on cross-polarized wave generation (XPW) is proposed for the temporal contrast measurement, where XPW process has advantages of higher energy conversion efficiency, more compact setup, and less sensitivity to misalignment in comparison self-diffraction process. The measurement dynamic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>1</mml:mn> </mml:mrow> <mml:msup>...

An improved single-shot fourth-order auto-correlator for temporal contrast measurement is proposed, in which spectral broadening based on self-phase modulation, followed by filtering, used sampling pulse generation. When the input energy 5.5 mJ, device has a dynamic range of 3 × 10−11, resolution approximately 200 fs, and time window 68 ps single shot. In addition, benefiting from sCMOS camera data acquisition system, accuracy self-verified using simply tilted glass plate optical path pulse....

We study population distributions and lasing actions of N_2^+ driven by femtosecond lasers with various wavelengths, uncover an efficient ionic excitation mechanism induced synchronized ionization multiphoton resonance. Our results show that the strongest appears around 1000 nm pump wavelength. At optimal wavelength, pump-energy threshold for air generation is reduced five folds compared required previous 800 laser. Simulations based on ionization-coupling model indicate although...

Light carrying orbital angular momentum (OAM) holds unique properties and boosts myriad applications in diverse fields from micro- to macro-world. Endeavors have been made manipulate the OAM order generate on-demand structured light explore novel of light. However, generation an ultrafast wave packet numerous vortices with various modes, that is vortex string, has rarely explored remains a significant challenge. Moreover, methods enable parallel detection all string are lacking. Here, we...

Fabrication of a periodic plasma density structure in gas jet with boundary scale length approaching 10 μm was demonstrated. This technique has potential applications various transient high-field photonic devices. The capability fabrication gas/plasma structures is the key to development devices such as plasma-based particle accelerators, x-ray lasers, high-harmonic generation, nonlinear optics, etc. For instance, laser wakefield electron accelerator, it proposed that by creating sharp...

Spatiotemporal optical vortex (STOV) is a unique with phase singularity in the space-time domain and photons STOV can carry transverse orbital angular momentum (OAM). The shows many fantastic properties which are worth exploring. Here, we theoretically experimentally study diffraction property of STOV, fundamental wave phenomenon. behaviors STOVs obviously affected by OAM. patterns pulses diffracted grating show multi-lobe structure each gap corresponding to 1 topological charge. lights OAM...