We demonstrated a method to improve the output performance of a Ti:sapphire laser in the long-wavelength low-gain region with an efficient stimulated Rama

We demonstrated a method to improve the output performance of a Ti:sapphire laser in the long-wavelength low-gain region with an efficient stimulated Raman scattering process. By shifting the wavelength of the high-gain-band Ti:sapphire laser to the long-wavelength low-gain region, high-performance Stokes operation was achieved in the original long-wavelength low-gain region of the Ti:sapphire laser. With the fundamental wavelength tuning from 870 to 930 nm, first-order Stokes output exceeding 2.5 W was obtained at 930–1000 nm, which was significantly higher than that directly generated by the Ti:sapphire laser, accompanied by better beam quality, shorter pulse duration and narrower linewidth. Under the pump power of 42.1 W, a maximum first-order Stokes power of 3.24 W was obtained at 960 nm, with a conversion efficiency of 7.7%. Furthermore, self-mode-locked modulations of first- and second-order Stokes generation were observed in Ti:sapphire intracavity solid Raman lasers for the first time.show less

A power splitter with a wideband arbitrary splitting ratio, which provides flexibility and adaptability in forming photonic devices such as microring reso

A power splitter with a wideband arbitrary splitting ratio, which provides flexibility and adaptability in forming photonic devices such as microring resonators and Mach–Zehnder interferometers, proves to be essential in photonic integrated circuits (PICs). We designed and fabricated a directional coupler-based power splitter with a wideband arbitrary splitting ratio and a microring resonator with a wideband uniform extinction ratio (ER) based on artificial gauge field (AGF) optimization. The neural network-aided inverse design method is applied to complete the target. Less than 0.9 dB power splitting variation and 1.6 dB ER variation have been achieved experimentally over a 100-nm bandwidth. Wideband performance, design efficiency, and device compactness are obtained by utilizing this optimization, which indicates great potential and universality in PIC applications.show less

A single molecule is the building block of the material world and the smallest independently stable unit. Exploring single-molecule properties using optic

A single molecule is the building block of the material world and the smallest independently stable unit. Exploring single-molecule properties using optical, photonic, and optoelectronic techniques holds great scientific significance in revealing the molecular dynamics, molecular structures, and molecular quantum properties. Nano-optical techniques, such as single-molecule photoluminescence and Raman scattering, not only enable a comprehensive analysis of interactions and conformational dynamics through spectral analysis but also provide unparalleled insights into elucidating the intricate structure of single molecules through atomic-resolution imaging. The research of photonics based on single-molecule electroluminescence has brought new ideas and limitless possibilities to the design and manufacture of photonic information devices. Single-molecule optoelectronics, which leverages photoexcitation to modulate electrical properties, has significant contributions to elucidating charge transport characteristics and optimizing the optoelectronic functions realized by single-molecule devices. Moreover, the optoelectronic characterization based on the interaction of ultrafast optical pulses with single molecules provides unprecedented opportunities for exploring their dynamic behavior and regulation laws on ultrafast time scales. We provide a timely and comprehensive overview of the latest significant advancements pertaining to the optical, photonic, and optoelectronic properties of single molecules, thereby presenting a fresh perspective for research across diverse fields, including single-molecule photophysics and photochemistry.show less

Conservation of parity plays a fundamental role in our understanding of various quantum processes. However, it is difficult to observe in atomic and molec

Conservation of parity plays a fundamental role in our understanding of various quantum processes. However, it is difficult to observe in atomic and molecular processes induced by a strong laser field due to their multiphoton character and the large number of states involved. Here we report an effect of parity in strong-field Rydberg-state excitation (RSE) by comparing the RSE probabilities of the N2 molecule and its companion atom Ar, which has a similar ionization potential but opposite parity of its ground state. Experimentally, we observe an oscillatory structure as a function of intensity with a period of about 50 TW/cm2 in the ratio between the RSE yields of the two species, which can be reproduced by simulations using the time-dependent Schrödinger equation (TDSE). We analyze a quantum-mechanical model, which allows for interference of electrons captured in different spatial regions of the Rydberg-state wave function. In the intensity-dependent RSE yield, it results in peaks with alternating heights with a spacing of 25 TW/cm2 and at the same intensity for both species. However, due to the opposite parities of their ground states, pronounced RSE peaks in Ar correspond to less pronounced peaks in N2 and vice versa, which leads to the period of 50 TW/cm2 in their ratio. Our work reveals a novel parity-related interference effect in the coherent-capture picture of the RSE process in intense laser fields.show less