The laser-initiated thermal (optothermal) switching of cholesteric liquid crystals (CLCs) is characterized by using different azobenzene (Azo) derivatives and laser wavelengths. Under 405-nm laser irradiation, Azo-doped CLCs undergo phase transition from cholesteric to isotropic. No cis-to-trans photoisomerization occurs when the 405-nm laser irradiation is blocked because only a single laser i...

This Letter reports oscillation of a far-infrared (FIR) waveguide laser on individual Stark components of the 496-,Am transition in CH3 F by the application of an electric field across the laser medium. Stark shifting of vibrational-rotational absorption lines into coincidence with C02-laser pump lines giving rise to FIR oscillation in the rotational transitions was first observed in ammonia.' ...

Patterns on YBa2Cu3O6.87 films, laser written in O2 or N2 atmospheres, and with various writing power densities and scanning speeds, have been studied by Raman scattering. For laser writing in O2 at atmospheric pressure, with low power density and fast scanning speed, it is found systematically that the oxygen content of YBa2Cu3Ox can be reduced. Only when the writing power density is high and ...

Resonance transition rubidium laser (5P1/2→5S1/2) is demonstrated with a hydrocarbon-free buffer gas. Prior demonstrations of alkali resonance transition lasers have used ethane as either the buffer gas or a buffer gas component to promote rapid fine-structure mixing. However, our experience suggests that the alkali vapor reacts with the ethane producing carbon as one of the reaction products. ...

The possibility to achieve laser action at different THz frequencies employing the so-called vertical transition will be discussed. The intra-well or vertical optical transition presents a number of features that makes it an ideal candidate for a systematic study of resonant tunnelling and dephasing in quantum cascade lasers. Laser action at 3.5 THz with very low threshold employing a single qu...

We have investigated modifications of sapphire (0 0 0 1) surface with and without coating, induced by a single laser pulse with a 1054 nm wavelength, 2.2 ms duration, 7.75 mm spot and energy of 20–110 J. A holographic optical element was used for smoothing the drive beam spatially, but it induced small hotspots which initiated damage on the uncoated and coated surfaces. The individual damage ef...

Laser spectroscopic measurements of the ground state hyperfine splitting (HFS) in hydrogenlike heavy ions have triggered great interest because they can be used to test QED effects in extremely strong electric and magnetic fields. However, the interpretation of the experimental value is difficult because the uncertainty of the contribution of the nuclear magnetization distribution (Bohr-Weissko...

Optical Communications, vol. 370, pp. 150–155, (2016) Realization and characterization of single-frequency tunable 637.2 nm high-power laser J. Wang, J. Bai, J. He, and J. Wang We report the preparation of narrow-linewidth 637.2 nm laser device by single-pass sum-frequency generation (SFG) of two infrared lasers at 1560.5 nm and 1076.9 nm in PPMgO:LN crystal. Over 8.75 W of single-frequency con...

Laser-driven ultrafast electron emission offers the possibility of manipulation and control of coherent electron motion in ultrashort spatiotemporal scales. Here, an analytical solution is constructed for the highly nonlinear electron emission from a dc biased metal surface illuminated by a single frequency laser, by solving the time-dependent Schrödinger equation exactly. The solution is valid...