arXiv subjects

Xinghe Jiang

Publications and source records attributed to Xinghe Jiang.

3 recordsLinked to original sources

arXiv2026

Reconfigurable multi-tone mmWave/THz generation powered by high-efficiency Kerr parametric oscillation

Broadband and simultaneously accessible multi-tone millimeter-wave (mmWave) and terahertz (THz) signals are attractive for multi-band wireless communication and spectroscopy applications, yet their generation remains constrained by electronic bandwidth limitations and inefficient optical frequency conversion. Here, we demonstrate reconfigurable photonic generation of multi-tone mmWave/THz signals with comb spacings of 100, 200, 300, and 400 GHz, using a strongly asymmetric dual-ring silicon-nitride (SiN) microresonator and a broadband spiral plasmonic photomixer. A localized avoided-mode crossing (AMX) introduced by an auxiliary ring supports a fixed optical parametric oscillation (OPO) mode pair over an extended pump-detuning range, consistent with passive compensation of detuning-dependent phase mismatch. This enables a maximum pump-to-generated-line conversion efficiency of 67.3 % with 25.06 dB of pump depletion across different pump wavelength selections. Direct photomixing of these optical states produces simultaneous multi-frequency tones spanning 100 to 900 GHz without intermediate optical amplification. The generated carriers are further characterized through down-converted spectra, frequency-noise power spectral density (PSD), and Allan deviation measurements, yielding a \b{eta}-separation linewidth of 26 kHz at an observation time of 0.1 s. Optical modulation offers high radiated power levels exceeding 2 mW at 100 GHz at a duty cycle of 1 %, while mitigating thermal breakdown in the photomixer. High optical conversion efficiency, reconfigurable and selectable comb spacings, and broadband multi-tone generation on a chip-scale platform provide a compact route toward reconfigurable multi-band mmWave/THz sources for wireless communication, spectroscopy, and sensing.

physics.optics↗

arXiv2025

Detection and imaging of chemicals and hidden explosives using terahertz time-domain spectroscopy and deep learning

Detecting concealed chemicals and explosives remains a critical challenge in global security. Terahertz time-domain spectroscopy (THz-TDS) offers a promising non-invasive and stand-off detection technique owing to its ability to penetrate optically opaque materials without causing ionization damage. While many chemicals exhibit distinct spectral features in the terahertz range, conventional terahertz-based detection methods often struggle in real-world environments, where variations in sample geometry, thickness, and packaging can lead to inconsistent spectral responses. In this study, we present a chemical imaging system that integrates THz-TDS with deep learning to enable accurate pixel-level identification and classification of different explosives. Operating in reflection mode and enhanced with plasmonic nanoantenna arrays, our THz-TDS system achieves a peak dynamic range of 96 dB and a detection bandwidth of 4.5 THz, supporting practical, stand-off operation. By analyzing individual time-domain pulses with deep neural networks, the system exhibits strong resilience to environmental variations and sample inconsistencies. Blind testing across eight chemicals, including pharmaceutical excipients and explosive compounds, resulted in an average classification accuracy of 99.42% at the pixel level. Notably, the system maintained an average accuracy of 88.83% when detecting explosives concealed under opaque paper coverings, demonstrating its robust generalization capability. These results highlight the potential of combining advanced terahertz spectroscopy with neural networks for highly sensitive and specific chemical and explosive detection in diverse and operationally relevant scenarios.

physics.optics↗

arXiv2023

Polarization-diverse soliton transitions and deterministic switching dynamics in strongly-coupled and self-stabilized microresonator frequency combs

Dissipative Kerr soliton microcombs in microresonators has enabled fundamental advances in chip scale precision metrology, communication, spectroscopy, and parallel signal processing. Here we demonstrate polarization diverse soliton transitions and deterministic switching dynamics of a self stabilized microcomb in a strongly coupled dispersion-managed microresonator driven with a single pump laser. The switching dynamics are induced by the differential thermorefractivity between coupled transverse magnetic and transverse electric supermodes during the forward backward pump detunings. The achieved large soliton existence range and deterministic transitions benefit from the switching dynamics, leading to the cross polarized soliton microcomb formation when driven in the transverse magnetic supermode of the single resonator. Resultantly the pump laser always exists at the effective blue detuning of the transverse magnetic resonance, fundamentally mitigating the thermal destabilization barrier and improving accessibility of the soliton formation regime. Subsequently and secondly, we demonstrate two distinct polarization diverse soliton formation routes arising from chaotic or periodically modulated waveforms via pump power selection. The generated self stabilized supermode microcomb features an extraordinarily large soliton existence range, a variety of soliton state transitions with well defined pump laser tuning, high pump microcomb conversion efficiency, and low repetition rate phase noise.

physics.optics↗