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Experimental results of thermal lens measurements for Tris(2,2 -bipyridyl)iron(II) tetrafluoroborate solution are reported using the dual beam technique. The temporal evaluation of thermal lens was observed at input pump power of I=47 mW. The thermal lens effect was observed with increasing the pump power intensity as well. The evolution time of thermal lens and the fitting of the experimental transient curve were useful to evaluate the parameters of the Tris(2,2′-bipyridyl)iron(II) tetrafluoroborate solution.

This study aims to examine the effects of surrounding soil layers and furthermore lens properties on induced vibrations by underground railway twin tunnels and comparing with the single tunnel. Fir...

Numerical and experimental studies were investigated for the self-Q-switching Nd:LuAG laser which was achieved by the Kerr lens effect. By applying two output couplers of 6% and 1.4%, the shortest pulses of 193.4 ns and 5.1 ns were generated respectively while the corresponding repetition rates were 1.175 MHz and 96.15 MHz respectively. Related to the average powers of 3.34 W and 2.56 W, the system demonstrated the optical to optical efficiency of 21.87% and 21.1% for coupler of 6% and 1.4% respectively. The short pulses with the high repetition rates can be applied in many fields which demonstrate the high value of the research on this self-Q-switching laser.

Velocity fields can be reconstructed at cosmological scales from their influence on the correlation between the cosmic microwave background and large-scale structure. Effects that induce such correlations include the kinetic Sunyaev Zel'dovich (kSZ) effect and the moving-lens effect, both of which will be measured to high precision with upcoming cosmology experiments. Galaxy measurements also provide a window into measuring velocities from the effect of redshift-space distortions (RSDs). The information that can be accessed from the kSZ or RSDs, however, is limited by astrophysical uncertainties and systematic effects, which may significantly reduce our ability to constrain cosmological parameters such as $f\sigma_8$. In this paper, we show how the large-scale transverse-velocity field, which can be reconstructed from measurements of the moving-lens effect, can be used to measure $f\sigma_8$ to high precision., Comment: 7 pages, 5 figures, comments welcome

This proposed article seeks to analyse the Hariyali guidelines in order to show how a capitalistic, managerial and scientific rationale is used which presumes that nature in order to be valued must have a productive value. As a capitalist enterprise, nature is only useful if it serves the livelihood needs of the populace. All other values are elided in favour of one overarching idea of productivity for the market. This productivity is sought to be harnessed through the twin ideas of proper managerial and scientific principles. The ‘Watershed Users Association’ is premised on the principle of people being rational maximisers who will put aside their caste, gender, religious and class differences in order to transform the topographical watershed into a productive entrepreneurial community enterprise. On the ground, people of course manage to subvert and resist these processes even as they acquiesce in the larger development plan.

Directly measuring thermal focal length is important for designing and optimizing the mode-locking oscillator, especially for a 2 μm mode-locking laser. In this paper, we propose a novel interferometric method for measuring the thermal focal length in a 2 μm mode-locking laser. This method provides a precise measurement of the thermal focal length inside a long-folded oscillator in both lasing and non-lasing operation. We also theoretically calculate the thermal focal length based on the temperature distribution inside the laser crystal, which matches well with the experimental results.

In high-pulse-energy Ti:sapphire amplifiers with moderate repetition rate, the thermal lens effect can significantly decrease the energy extraction efficiency and increase the risk of optical damage. A new method, without introducing any additional components, is proposed to suppress the thermal lens effect in such amplifiers. By utilizing a particularly designed beam expander before the amplifier, specific expanding ratio and beam divergence can be introduced to the injected seed pulses, which can improve the spatial matching between the seed pulses and the pump pulses, and thus enhance the energy extraction efficiency. The enhancement of the energy extraction efficiency has reached approximately 10% in our experimental four-pass Ti:sapphire amplifier, and the good agreement between theoretical and experimental results also demonstrates the validity and feasibility of this method.

To reduce the thermal lens effect and increase the efficiency, a composite crystal of Nd3+:YAG/Cr4+:YAG/YAG and a coupled cavity structure were employed in our passively Q-switched YVO4-based Raman laser system. Both the simulation and the experiment results showed that the undoped YAG crystal bonded in the end-face of Cr4+:YAG crystal can speed up the heat transfer of Cr4+:YAG crystal and reduce the temperature difference between its side surfaces and the center significantly, and the coupled cavity structure can improve the laser performance, especially at high pump power. The maximum output power of Raman laser of 0.92 W at 1176 nm was obtained with an optical-to-optical efficiency of 11.51%. The corresponding repetition rate and the pulse width is 53.5 kHz and 3.22 ns, respectively.

A hybrid trapped field magnet lens (HTFML) is a promising device that is able to concentrate a magnetic field higher than the applied field continuously, even after removing an external field, which was conceptually proposed by the authors in 2018. This paper presents, for the first time, the experimental realization of the HTFML using a GdBaCuO magnetic lens and MgB2 trapped field magnet cylinder. A maximum concentrated magnetic field of B c = 3.55 T was achieved at the central bore of the HTFML after removing an applied field of B app = 2.0 T at T = 20 K. For higher B app, the B c value was not enhanced because of a weakened lens effect due to magnetic flux penetration into the bulk GdBaCuO material comprising the lens. The enhancement of the trapped field using such an HTFML for the present experimental setup is discussed in detail.

Gravitational potentials which change in time induce fluctuations in the observed cosmic microwave background (CMB) temperature. Cosmological structure moving transverse to our line of sight provides a specific example known as the moving lens effect. Here we explore how the observed CMB temperature fluctuations combined with the observed matter over-density can be used to infer the transverse velocity of cosmological structure on large scales. We show that near-future CMB surveys and galaxy surveys will have the statistical power to make a first detection of the moving lens effect, and we discuss applications for the reconstructed transverse velocity., 5 pages, 4 figures, comments welcome

We investigate the prominent role of 4 f system in the suppression of beam shape distortion during laser power amplification. We find that 4 f system can effectively suppress the distortion of the light spot caused by diffraction and thermal lens effect. In addition, the laser power can be amplified more efficiently by introducing a 4 f system. Our results can benefit for applications with high requirements on the spot shape such as optical lattice and optical information processing.

The anisotropic thermal lens effect of a dual-polarization Nd:YLF laser is experimentally investigated by measuring the transverse beat frequency between T E M 0 , 0 and T E M 1 , 0 modes in the self-pulsing operation, and focal lengths of thermal lensing for both polarizations can be accurately determined. The focal length of the thermal lens for π polarization was observed to be negative and varies from − 1.1 to − 0.5 m for the absorbed pump power increasing from 1.7 to 3.8 W. For σ polarization, the focal length of the thermal lens was determined to be positive and varies from 1.2 to 0.9 m for the absorbed pump power increasing from 8.4 to 10.9 W. The sensitivity factors of the thermal lens for both polarizations were evaluated to be M π = − 0.54 m − 1 / W and M σ = 0.1 m − 1 / W , respectively.

For obtaining efficient passively Q-switched laser at 473 nm, an Nd:YAG/YAG/Cr 4+ :YAG/YAG composite crystal and a coupled cavity were employed to reduce the thermal lens effect and enable the laser system operating on high pumped power. In our experiment, the maximum average output power of 0.81 W was obtained with the repetition rate of 28.5 kHz and the pulse width of 104 ns at the pumped power of 9.79 W, corresponding to an optical-to-optical conversion efficiency of 8.27%.

espanolUsando interferometria y analisis de Fourier se obtiene un mapa de fase fototermico en un liquido de alta absorbancia a la longitud de onda del laser que induce el efecto fototermico. El montaje experimental consiste en una adaptacion del experimento de lente termica de dos haces, en el cual ambos brazos de un interferometro de Sagnac son utilizados como haces de prueba. Los interferogramas son registrados con una camara CCD y posteriormente procesados utilizando tecnicas de analisis de Fourier. Los resultados obtenidos muestran que el coeficiente de difusividad termica de la muestra de alta concentracion de Tartracina en agua es mayor al del agua pura. La tecnica puede ser utilizada para estudiar transferencia de calor en muestras opacas a la longitud de onda del haz de excitacion EnglishUsing interferometry and Fourier analysis, the photothermal phase map is obtained from the induced thermal lens effect in a liquid sample with high absorbance at the laser wavelength. The experimental setup consists of an adaptation of two beams thermal lens experiment, where both arms of a Sagnac’s interferometer are used as probe beams. The interferograms are recorded with a CCD camera and then processed using Fourier analysis techniques. The results show that the coefficient of thermal diffusivity of a high concentrated water solution of Tartrazine is greater than that of pure water. The technique can be used to study heat transfer in opaque samples to the wavelength of the excitation beam

Sodium dodecyl sulfate polyacrylamide gel electrophoresis is a standard biochemical technique to separate, detect and quantify protein amounts of specific molecular weights. Colorimetric detection with Coomassie or silver stain is by far the most common analysis method. Silver stain is the most sensitive one and protein bands down to 1 ng can be detected with laboratory imaging systems. To increase the sensitivity of the detection we developed a sensor based on the principle of the thermal lens effect to scan, record, and quantify protein bands not visible to the eye or to the camera. Our device could detect bands of 0.05 ng in gels soaked in methanol/water and 0.1 ng when soaked in water.

In this work, we revise the model describing laser heating of a spherical metallic nanoparticle (NP) immersed in transparent oil. We study the generated temperature non-uniformity of the ambient medium and its effect on the propagation of the laser beam. Thus, the model describes the influence of thermal non-uniformity on scattering and absorption of light by the heated particle. Recently, different aspects of the heating of NPs by a laser beam have been actively researched. Some experimental works demonstrated an enigmatic dependence of the effective scattering cross-section of the heated particle on the intensity of the laser beam, illuminating it. The authors of these works labeled the observed effects as “saturation,” and “reverse saturation.” In this paper, we show that the propagation of the incident laser beam in a non-uniform oil can by itself be the source of both “saturation” and “reverse saturation” els effects.

The boronized Ti6Al4V/hydroxyapatite (HA) composites were fabricated by facile microwave sintering of mixed powders of Ti6Al4V, HA and TiB2 at 1050 °C for 30 min, with a focus on the effects of HA addition (0–10 wt%) on the mechanical properties of the resulting composites for loading-bearing biomedical applications. Due to phase and microstructural evolutions, there were two stages of the variations of mechanical properties. In stage I with addition of less than 5 wt% HA, there existed only modest decreases of the properties contributed by the “lens effect” of microwave and the “buffer effect” of TiB. In stage II with higher HA addition, the properties of the composite declined rapidly mainly due to more and unevenly distributed pores with poorer densification of the matrix. The composite synthesized with addition of 5 wt% HA exhibited the optimal and superior mechanical properties compared with other types of related composites and natural bones.

We designed a 5-mirror alexandrite laser cavity considering thermal lens effect to avoid damage at the surface of the mirror.

100Hz operation in the PW/sr/cm2-class Micro-MOPA was achieved by evaluating thermal lens effect of highly excited Nd:YAG-rod in sub-ns 100-mJ class main amplifier and optimizing optics design.

The thermal lens effect of Nd:YLF crystal for different polarized beams is experimentally and theoretically studied in this paper. In the experiment, the different thermal lens effects of Nd:YLF crystal along a and c axes for π- and σ-polarized probe beams are observed, and the values of the focal lengths are measured. The theoretical analysis is made to explain the extremely weak thermal lens effect along the c axis, as well as that for the σ-polarized beam. And it is corroborated that the complementation among the thermo-optical coefficient, the thermal end bulging and the photoelastic effects contributes to the weak and asymmetry thermal lens effect of Nd:YLF crystal.

We demonstrate a photonic crystal-based method that is capable of enhancing the photothermal lens effect generated by light absorbing materials. The method was used to analyze gold nanoparticles and exhibited stronger photothermal lens signals.

We report on a successful topographical and optical imaging of various cancer cells in liquid and in air by using a stable wet near-field scanning optical microscope that utilizes a resonance tracking method. We observed a clear dehydration which gives rise to a decrease in the cell volume down to 51%. In addition, a micro-ball lens effect due to the round-shaped young cancer cells was observed from near-field imaging, where the refractive index of young cancer cells was deduced.

The results of numerical modeling of conjugate heat transfer in an IGU with account for its deformation caused by excessive negative pressure in the glazing cavity are presented in the article. The influence of the IGU glass pane deformation on thermal characteristics and gas flow regime within the cavity are studied. A method of assessment of reduced thermal resistance of IGU is provided. The effects of different climatic impacts lead to the deformation of glasses within an IGU (and its vertical cavity, respectively). Deformation of glasses and vertical cavities reduces the thermal resistance of an IGU. A numerical simulation of conjugate heat transfer within an IGU was implemented as part of the research into this phenomenon. Calculations were performed in ANSYS FLUENT CFD package. Basic equations describing the conservation of mass, conservation of momentum (in the Boussinesq approximation), conservation of energy were solved. Also, the radiation of the cavity wall was taken into account. Vertical walls were considered as non-isothermal, while horizontal walls were adiabatic. Calculations were made for several patterns of glass deformations. Calculation results demonstrate that the heat flow over vertical walls intensifies as the distance between centres of IGU glasses is reduced. The temperature in the central area of the hot glass drops.

By inserting an intracavity DKDP slice with negative thermal lens effect into a single-frequency and frequency-doubled laser, the harmful effect of TGG is actively compensated and the highest output power of 30.2 W is achieved.

We demonstrate a new Q switching technique that exploits the polarization dependence of the thermal lens effect of a cut uniaxial gain media within a range of pump powers.