Topic: Next Generation Octave Spanning Coherent Light Source from Ta2O5-based Nonlinear Waveguide
Speaker: Prof. Chao-Kuei Lee
Time: Wednesday, July 24, 2024, 9:30-11:30 a.m.
Venue: B707, New Main Building, Xueyuan Road Campus
Abstract:
Supercontinuum generation (SCG) represents the generation of ultra-broadband optical spectrum by injecting a short pulse into a nonlinear optical material. SCG involves complex nonlinear optical processes related to c of nonlinear medium, including self-phase modulation (SPM), crossphase modulation (XPM), four-wave-mixing (FWM), soliton fission, Raman self-frequency shift, and dispersive wave generation. Such broadband optical spectrum shows great optical coherence within the full optical bandwidth and can be utilized in frequency metrology, optical coherence tomography, coherent Raman and anti-stokes Raman spectroscopy.
In this work, anomalous dispersion Tantalum Pentoxide Ta2O5-based waveguide was designed for SCG due to its nature of two photon absorption free and high optical nonlinearity. The e-beam lithography and reactive ion etching are utilized to fabricate the waveguide structure. By injecting a 100-fs pulse laser at central wavelength of 1-um, the output spectrum of Ta2O5 waveguide shows an octave spanning (at -30dB) under excitation peak power of around few hundred Watt. In addition, the SCG from various dimension Ta2O5 waveguide was investigated and discussed. Beside the air-cladding structure, the SCG from Ta2O5 higher order mode channel waveguide will be discussed in the talk as well. Our result shows that Ta2O5 has great potential in developing visible to infrared broadband light source, which can be applied in frequency metrology and quantum technology. Meanwhile, the high speed all optical modulation based on Ta2O5 waveguide will be introduced if possible.
About the Speaker:
Prof. Chao-Kuei Lee is a professor in the Department of Photonics and Department of Physics at National Sun Yat-sen University (NSYSU), and a research fellow at the Research Center of Applied Science (Academic Sinica). He received his doctoral degree from the Institute of Optoelectronics in National Chiao Tung University in 2003. Since then, he has led Femtosecond and Quantum Modulation Lab at NSYSU and has been working in the field of quantum electronics. His research interest mainly focuses on photonics and optoelectronics, including the ultrafast phenomena, Si Photonics, THz photonic, Laser technology and nonlinear optics. In the last two decades, Prof. Lee published over 100 journal papers.
School of Instrumentation and Optoelectronic Engineering
