Qinghai Song

Microfiber knot dye laser based on the evanescent-wave-coupled gain

The authors demonstrate a composite microring laser formed by immersing a silica microfiber knot in a rhodamine 6G dye solution. When the dye molecules are evanescently pumped by 532nm wavelength laser pulses guided along a 350μm diameter knot, lasing oscillation occurs inside the evanescently coupled closed-ring microcavity with a linewidth of about 0.06nm. Laser emission around 570 and 580nm wavelengths, which is evanescently coupled back into the microfiber, is observed with a threshold of about 9.2μJ∕pulse. The use of the microfiber knot cavity suggests a convenient and efficient approach to both pumping and collection of the evanescent-wave-coupled dye laser.

Electrical tunable random laser emission from a liquid-crystal infiltrated disordered planar microcavity

Here we report electric-field-induced, wavelength-tunable random lasing action in a liquid-crystal infiltrated disordered planar microcavity. With the increasing of external voltage from 0 V to 30 V, the emission wavelength of the random laser was continuously tuned from 648 nm to 597 nm. It was also tuned back to 648 nm again by reducing the voltage back to 0 V.

Liquid-crystal-based tunable high-Q directional random laser from a planar random microcavity.

Temperature-tunable directional laser emission from a dye-doped liquid-crystal-based planar random cavity laser is presented. The optically pumped nematic liquid crystal infiltrated planar random microcavity produces an ultranarrow linewidth (0.03nm, corresponding to Q>20,000), highly directional (1.4° divergence angle) laser emission. By increasing the temperature from 27°C to 34°C, the wavelength of an emitted polarized laser can be tuned between 605.8 and 608.5 (ordinary light) and 631.3 and 624.9 nm (extraordinary light). A simulation result from the transfer matrix method that matches the experimental results well is also presented.

Surface electronic structure and isotropic superconducting gap in ( Li 0.8 Fe 0.2 ) OH Fe Se

Using angle-resolved photoemission spectroscopy (ARPES), we revealed the surface electronic structure and superconducting gap of (Li

Intense directional lasing from a deformed square-shaped organic-inorganic hybrid glass microring cavity

_{0.8}

Presence of exotic electronic surface states in LaBi and LaSb

Fe

Narrow-band polarized light emission from organic microcavity fabricated by sol-gel technique

_{0.2}

Lasing Action in Dye Doped Polymer Nanofiber Knot Resonator

)OHFeSe, an intercalated FeSe-derived superconductor without antiferromagnetic phase or Fe-vacancy order in the FeSe layers, and with a superconducting transition temperature (

Switchable Random Laser From Dye-Doped Polymer Dispersed Liquid Crystal Waveguides

T_c

High-Q-preserving coupling between a spiral and a semicircle μ-cavity

)