Organic-inorganic lead-halide perovskites have been the subject of recent intense interest due to their unusually strong photovoltaic performance. A new addition perovskite family is all-inorganic Cs-Pb-halide nanocrystals, or quantum dots, fabricated via a moderate-temperature colloidal synthesis. While being only recently introduced research community, these nanomaterials already shown promise for range applications from color-converting phosphors and light-emitting diodes lasers, even...

The use of semiconductor nanocrystal quantum dots (QDs) in optoelectronic devices typically requires postsynthetic chemical surface treatments to enhance electronic coupling between QDs and allow for efficient charge transport QD films. Despite their importance solar cells infrared (IR) light-emitting diodes photodetectors, advances these lead chalcogenide (PbE; E = S, Se, Te) have lagged behind those of, instance, II–VI QDs. Here, we introduce a method fast effective ligand exchange PbE...

Understanding the mechanism of water adsorption on silica is important in many fields science and technology, such as geo- atmospheric chemistry. Vibrational IR–visible sum-frequency generation (SFG) spectroscopy hydroxyls (∼3100–3800 cm–1) at amorphous SiO2 surface contact with air varying relative humidity provides information about sites orientation molecules. The similar magnitudes resonant nonresonant contributions to interfacial second-order susceptibility, χ(2), allow phases various...

Vibrational sum-frequency generation (SFG) spectroscopy of interfacial water at mineral/aqueous interfaces is extended to the near-IR range containing low cross section stretch + bend combination bands (νcomb = νOH δHOH) liquid silica surfaces near 5000-5300 cm(-1), for first time. The assignments SFG spectra are supported by FTIR and Raman spectroscopic measurements bulk νcomb modes. contain significant contributions from two combinations, [νs δ] ≈ 5060 cm(-1) [νas 5300 cm(-1). These...

Non-collinear optical parametric amplification in potassium-titanyl phosphate (KTP) pumped with 800 nm pulses is reported. Broadband phase matching achieved non-collinear geometry and a slightly divergent signal seed. This enables gain bandwidth up to approximately 2500 cm(-1) near-IR region. Introducing chirp into the pump pulse makes it possible amplify white light seed broad spectral region from 1050 1400 simultaneously. Pulse compression sub-40 fs readily achieved, while spectrum should...

Noncollinear optical parametric amplifiers (NOPAs) pumped with ultrashort subpicosecond pulses often suffer from pulse-front tilting, resulting in angular dispersion and noncompressibility of the amplified signal pulses. We show that matching (PFM) a prism-telescope setup corrects for tilts near-IR NOPA. discuss conditions lead to tilt NOPA-amplified pulses, thus requiring mismatch correction. review method PFM describe application an 800 nm NOPA based on 2-mm-thick bulk potassium-titanyl...

We describe an ultrabroadband IR-visible sum-frequency (SF) setup that allows simultaneous acquisition of the entire vibrational spectrum water molecules at mineral surfaces in OH stretching region without ever tuning IR laser pulses. Our newly developed 800-nm pumped noncollinear optical parametric amplifier (NOPA) generates broadband mid-IR pulses (~1800-3500 nm, or ~2900 - 6000 cm-1) with bandwidths >600 cm-1 half-maximum near 3500 cm-1. Using ultra-broadband NOPA, we constructed a...

We report efficient noncollinear optical parametric amplification (NOPA) of ultrabroadband near-IR pulses tunable in the 1.1-1.5 μm range at a repetition rate 250 kHz. Improved generation smooth continua (extending over ~1.0-1.6 μm) kHz was achieved by weakly focusing ~20% 1 W driving laser beam into sapphire plate with longer focal length lenses than previously reported. Using bulk potassium-titanyl phosphate (KTiOPO(4)) pumped 800 nm, powers as high 11 mW (14% pump conversion efficiency)...

We describe temporal compression of ultrabroadband, few microjoule mid-infrared (mid-IR) pulses from a noncollinear optical parametric amplifier (NOPA) employed in sum-frequency generation (SFG) vibrational spectroscopic system, operating total-internal-reflection geometry. The propagation the mid-IR beam through materials results significant chirp at probed interface, which is analyzed and corrected by properly managing total dispersion introduced into path. By employing simultaneous...

We describe a near-IR two-stage noncollinear optical parametric amplifier (NOPA) pumped at 800 nm that employs bulk congruent lithium niobate [LiNbO3 (c-LNB)] and potassium [KNbO3 (KNB)] crystals. Noncollinear phase matching in these materials allows for generation of pulses as broad 2900 cm−1 (∼78 THz) centered the ∼1300 nm. In particular geometry described here, LNB crystal amplifies white-light seed continuum, KNB further broadband pulses. Use pulse-front both nonlinear crystals...

In the article contribution of engineer and academician І.H. Aleksandrov (1875-1936) to solution power providing problems in Eastern Siberia has been highlighted. Ivan HavrylovychAleksandrov considered problem Angara Yenisei basin not only as a scientist an but also statesman who took care technical economical country’s strengthening. The describes role river national USSR’s economy forming well. Aleksandrov’s scientific labours turned into radical transformations whole Siberia. Working out...

Abstract Optically active phonon modes in ferroelectrics such as potassium titanyl phosphate (KTP) and arsenate (KTA) the ~7–20 THz range play an important role applications of these materials Raman lasing terahertz wave generation. Previous studies with picosecond pulse excitation demonstrated that interaction pump pulses phonons can lead to efficient stimulated scattering (SRS) accompanying optical parametric oscillation or amplification processes (OPO/OPA) polariton-phonon scattering. In...

We report on generation of ultra-broadband (>2900 cm−1) near-IR pulses from non-collinear optical parametric amplifier based congruent lithium niobate and potassium bulk crystals pumped at 800 nm.

We report on considerable photon energy losses of [signal+idler] pair (~60 meV) in KTiOPO4 optical parametric amplifier pumped by <40-fs 800-nm pulses and explain it rectification enhanced coupling to large third-order nonlinearity.

One of the most important tasks modern history science and technologies is study activities leading scientists practitioners past, influence their ideas on development world process training specialists in relevant sectors national economy. In opinion authors article, one such figures early twentieth century Academician I. H. Aleksandrov. Historical scientific analysis life activity Aleksandrov as a scientist, engineer, organizer high topicality due to scale versatility his contribution....

We demonstrate that coherently-excited Raman-/IR-active phonons in certain nonlinear optical crystals (KTiOPO4, KTiOAsO4) significantly affect the operation of ultrashort-pulse pumped parametric amplifiers. The photon-phonon coupling these materials leads to non-instantaneous, pump-dependent 2nd-order susceptibility.

We demonstrate broadband non-collinear optical parametric amplification of near-IR pulses in bulk KTiOPO4 pumped with 800-nm at 250-kHz repetition rate. Conversion efficiencies ~20% are achieved when employing two subsequent NOPA stages.

800-nm pumped BIBO OPAs using Type-I and Type-II phase-matching are investigated compared for achieving sub-50-fs pulses in the NIR. The achieve their shortest pulse durations of 19.8fs 41.3fs, respectively, at 1.8µm.

We apply pulse-front matching to a near-IR non-collinear optical parametric amplifier based on bulk KTiOPO4 crystal. Pulses as broad ~32 THz at ~1200 nm with almost no angular dispersion could be produced.

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