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Abstract: Between November 23 and 28, 2007, the Cologne Tuneable Heterodyne Infrared Spectrometer THIS was installed at the McMath-Pierce Solar Telescope (Kitt Peak, Arizona, USA) to determine zonal wind velocities and to estimate the subsolar-to-antisolar flow. We investigate dynamics in the upper atmosphere of Venus by measuring the Doppler shift of fully-resolved non-LTE CO2 emission lines at 959.3917cm−1 (10.423μm), which probe a narrow altitude region in Venus’ atmosphere around 110±10km (∼1μbar). The results show no significant zonal wind velocity at the equator. An increase with latitude up to 43±13m/s at a latitude of 33°N was observed. This confirms the deduction of a minor influence of Venus superrotation at an altitude of 110km from previous measurements in May 2007 (). The specific observing geometry enables estimating the maximum cross terminator velocity of the subsolar-to-antisolar flow at 72±47m/s. [Copyright &y& Elsevier]

Abstract: A study of the CO2 atmospheric emissions at 10-μm in the upper atmospheres of Mars and Venus is performed in order to explain a number of ground-based measurements of these emissions recently taken at very high spectral resolution in both planets. The measurements are normally used to derive atmospheric temperatures and winds, but uncertainties on the actual emission layers were so far a serious drawback for their correct interpretation. The non-LTE models used for Mars and Venus in the present analysis are entirely similar in order to perform consistent comparisons between the two planets. In particular, the same scheme of CO2 states and ro-vibrational bands are used, with similar assumptions on collisional routes and rate coefficients, and also the same radiative transfer approximations. The emissions at 10-μm are produced in both atmospheres by the same excitation mechanism: radiative pumping of the CO2(0001) vibrational state by direct solar absorption(at 4.3μm) and indirect absorption (at 2.7μm, followed by collisional quenching). The computed radiances are specially strong in the upper mesosphere and lower thermosphere of the two planets during maximum solar illumination, producing a population inversion in such conditions with the lower states of the bands, the CO2 (1000) and CO2(0200). We obtained that other population inversions are also possible, involving higher energy CO2 states. The larger solar flux available on Venus is found to produce larger vibrational populations and stronger emissions than equivalent atmospheric layers on Mars, in agreement with the observations. A number of perturbation studies were used to determine the exact emission altitudes, or weighting function peaks, for usual nadir sounding. The sensitivity of the emission to non-LTE model uncertainties and to atmospheric variations in temperature and CO2 density is also presented. The dependence with the solar zenith angle and with the emission angle, as obtained with this model, could also be useful for guiding future observations. [Copyright &y& Elsevier]

Abstract: We report observations of Venus atmospheric wind near 110km altitude by means of high-resolution mid-infrared spectroscopy. Data were acquired May 28–June 4, 2007 at the McMath-Pierce Solar Telescope (Kitt Peak, Arizona, USA), during a coordinated ground-based observing campaign in support of Venus Express. The Cologne Tuneable Heterodyne Infrared Spectrometer (THIS) was used to measure the Doppler shift of fully resolved non-LTE emission lines of CO2 at ) to determine wind velocity. Spatial resolution was on Venus’ apparent diameter of 20–22arcsec. Zonal wind velocities were retrieved at six different latitudes close to the west limb. Retrieved zonal velocities—parallel to Venus’ retrograde solid body rotation—range at the equator to a maximum of at southern mid-latitude , decreasing at higher latitudes and thus suggesting a retrograde double jet structure for the zonal component. The subsolar-to-antisolar circulation component was measured at one position, towards the sunlit limb from the central meridian, on the equator. The retrieved subsolar-to-antisolar component at this position implies a cross-terminator velocity of . Retrieved velocities are lower than previous results, suggesting spatial and/or temporal variability of dynamics in the mesosphere/thermosphere of Venus. [Copyright &y& Elsevier]

Chirped pulse amplification (CPA) and subsequent nonlinear optical (NLO) systems constitute the backbone of myriad advancements in semiconductor manufacturing, communications, biology, defense, and beyond. Accurately and efficiently modeling CPA+NLO-based laser systems is challenging because of the complex coupled processes and diverse simulation frameworks. Our modular start-to-end model unlocks the potential for exciting new optimization and inverse design approaches reliant on data-driven machine learning methods, providing a means to create tailored CPA+NLO systems unattainable with current models. To demonstrate this new, to our knowledge, technical capability, we present a study on the LCLS-II photo-injector laser, representative of a high-power and spectro-temporally non-trivial CPA+NLO system.

Background/aim: Picosecond infrared laser (PIRL) was investigated regarding its possible therapeutic application in cutting dental roots., Materials and Methods: Extracted human teeth were processed in the root area by laser ablations followed by histological evaluation. Dentin adjacent to the cutting surface was evaluated morphometrically., Results: PIRL produced clearly defined cutting boundaries in dental roots. At the bottom of the cavity, the ablation surface became slightly concave. Heat development in this scantly hydrated tissue was considerable. We attributed the excess heating effects to heat accumulation due to multiple pulse overlap across a limited scan range imposed by tooth geometries., Conclusion: Defined areas of the tooth root may be treated using the PIRL. For clinical translation, it would be necessary to improve beam delivery to facilitate beam steering for the intended oral application (e.g. by using a fiber) and identify optimal repetition rates/scan speeds combined with cooling techniques to minimize accumulated heat within ablation cavities., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

We present a new chromatic numerical approach to simulate the amplification of laser pulses in multipass laser amplifiers. This enables studies on spectral effects such as gain narrowing and spectral shaping with optical elements expressed by a transmission transfer function. We observe good agreement between our simulations and measurements with a Ho:YLF regenerative amplifier (RA). To demonstrate the capabilities of our simulation model, we numerically integrate an intra-cavity etalon in this laser and find optimum etalon parameters that enhance the peak power of the output pulses up to 65%.