Session Index

Within one year of the demonstration of the first laser, Q-switching was demonstrated, and resulted in high-peak power, short-pulse laser systems. Limitations of laser systems due to laser-induced damage on optical components followed. Short pulsed lasers have progressed as better optical materials with higher laser-resistance were developed, the nonlinear optical effects have been better understood and managed, and chirped pulse amplification technique was developed (the subject of the 2018 Nobel Prize in physics awarded to Gerard Mourou and Donna Strickland). In turn, high power, ultra-short pulse lasers have become an important tool in studying optical materials. In this work, we report studies of surface modifications in ZnSe with 11.5 fs, mid-infrared few-cycle pulses. Single shot and multi-shot laser irradiations were studied with terawatt power. Periodic surface structures were generated and growth defects were revealed as pulse number increased.

 

Quasi-3D nonlinear photonic crystals were realized in PPLT by diffusion process. Using degenerate OPO scheme, we observed ~1μm NIR generation with 3.27nm spectral shift in the depth direction and spectral gain width 7.9nm. These observations suggested that diffusion induced refractive index modulation is essential in determining the QPM parametric conversion.

 

To explore resonance phenomena in the nonlinear region, we show by experimental measurements and theoretical analyses that resonance happens in modulation instability from non-instantaneous nonlinearities in photorefractive crystals.

 

Thin metal films have been widely adopted to generate ultra-high frequency hypersound with ultrafast optical excitations through thermal expansion. To reach the frequency limitation, here we demonstrate photoacoustic generation up to 1.6 THz by using nano-thick Ni films. The possibility to generate even higher frequency hypersound waves will be discussed.

 

We report the single-photons detection performance of InGaAs/InP avalanche photodiode on Gated-Geiger-Mode operation. The dark-count probability of 2.67×10-3, single-photon detection efficiency of 11.66 %, and after-pulsing of <6% were obtained under the temperature of -30ºC, excess bias voltage of -2.8V, and gated-frequency of 10 MHz with 2 ns gated-pulse width.

 

Strain-balanced type-II InAs/InAsSb on GaSb substrate were designed for mid-wavelength photodetectors. In our work, we developed a 8×8 k.p Schrodinger model to calculate the band structure of InAs/InAs0.6Sb0.4 type II super lattice (T2SL), and studied its electronic properties, such as bandgap, absorption and mobility