Enhanced Higher Harmonic Generation in Modified MAPbBrCl Single Crystal by Additive Engineering.

Mixed-halide perovskite materials (MHSCs) hold significant interest in photonics applications owing to their inherent advantages, including tunable bandgap properties, remarkable defect tolerance characteristics, and facile processability. These attributes position MHSCs as up-and-coming materials for various applications. However, the commercialization of these materials is severely affected by external factors, such as humidity and oxygen.

Extension of high-order harmonic generation cutoff from laser-ablated tin plasma plumes.

The high-order harmonic spectra from laser-ablated tin plasma plumes are investigated experimentally and theoretically at different laser wavelengths. It is found that the harmonic cutoff is extended to ∼84 eV and the harmonic yield is greatly improved by decreasing the driving laser wavelength from 800 nm to 400 nm. Appling the Perelomov-Popov-Terent'ev theory with the semiclassical cutoff law and one-dimensional time-dependent Schrödinger equation, the contribution of the Sn ion to harmonic generation accounts for the cutoff extension at 400 nm.

Comparative study of medium length-dependent high-harmonic generation from metal ions.

We present an experimental study on the high-harmonic yields from the ions in the laser-ablated plumes of various metal targets (W, Mo, Cr, Cu, Ni, Fe, Ag and Mg) with the purpose of comparing their ion density and single-atom response. The harmonic yields as a function of medium length are measured and the results are fitted against a theoretical model to extract the coherence length, absorption length and strength single-atom response (in arbitrary units) of different harmonic orders for each target. It is found that the coherence lengths decrease monotonically as a function of harmonic order for all targets.

Investigation of high-harmonic cutoff of metal ions driven by near-infrared laser.

The cutoff-energies of high-harmonic generation in the laser-ablated plumes of various metal targets (Ca, Mg, Fe, Zn, Ta, Mo, Al, W, In, Cu, Au, Ti, Ag) driven by near-infrared (0.8-µm) femtosecond laser are investigated and compared. Due to the low ionization potentials of metal atoms, it is believed that the observed high-harmonic cutoffs are contributed by the singly charged or even doubly charged ions.

Distinguishing monomer and nanoparticle contributions to high-harmonic emission from laser-ablated plumes.

Nano-clusters and nano-particles (NPs) are attractive media for high-harmonic generation (HHG) since they combine the advantages of using atomic media (for the low average density) and bulk solid media (for the high local density). Recently, laser ablated plumes from metal nano-powders have been used as HHG media and it has been often assumed that the harmonics mainly come from the NPs in the plumes but not by the isolated atoms/ions. However, this assumption is yet to be fully justified.