52 research outputs found
Main Elements of Logistics
Virtually lossless self-compression of 10-mJ 3.9-um sub-100 fs pulses in bulk YAG resulting in 9-mJ 33-fs pulses is reported. Generated peak power exceeds 250 GW which is suitable for filamentation in ambient air
Probing Ultra-Fast Dephasing via Entangled Photon Pairs
We demonstrate how the Hong-Ou-Mandel (HOM) interference with
polarization-entangled photons can be used to probe ultrafast dephasing. We can
infer the optical properties like the real and imaginary parts of the complex
susceptibility of the medium from changes in the position and the shape of the
HOM dip. From the shift of the HOM dip, we are able to measure 22 fs dephasing
time using a continuous-wave (CW) laser even with optical loss > 97%, while the
HOM dip visibility is maintained at 92.3~\% (which can be as high as 96.7%).
The experimental observations, which are explained in terms of a rigorous
theoretical model, demonstrate the utility of HOM interference in probing
ultrafast dephasing.Comment: 12 pages, 7 figure
Enhanced Cerenkov Second-Harmonic Generation in Patterned Lithium Niobate
We present experimental results of second harmonic generation enhancement through the resonance of the band edge in a photonic crystal based on lithium niobate. Proton exchange technique was used to fabricate a waveguide near the surface of the lithium niobate substrate. The photonic crystal structure over the waveguide was made by UV laser interferometry. Subsequently experiments were designed to quantify the Cerenkov second-harmonic generation (CSHG) radiated into the substrate. The SHG radiated inside the waveguides was also experimentally investigated. In our experiments, the second guided mode of the waveguide was tuned to the band edge resonance to enhance the second harmonic generation. The highest conversion efficiency of CSHG using photonic band gap (PBG) was around 50 times compared to SHG emission from non-patterned lithium niobate. A numerical model was used to corroborate the experimental result. It was also found that the SHG signal in the waveguides is quenched compared to the CSHG signal
Ultralow-power local laser control of the dimer density in alkali-metal vapors through photodesorption
Ultralow-power diode-laser radiation is employed to induce photodesorption of
cesium from a partially transparent thin-film cesium adsorbate on a solid
surface. Using resonant Raman spectroscopy, we demonstrate that this
photodesorption process enables an accurate local optical control of the
density of dimer molecules in alkali-metal vapors.Comment: 4 pages, 4 figure
Coherence brightened laser source for atmospheric remote sensing
This article discusses the coherence brightened laser source for atmospheric remote sensing
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