A highly efficient photonic band edge dye-doped cholesteric liquid crystal (CLC) laser is demonstrated. By sandwiching an active CLC cell within a resonator consisting of two passive CLC reflectors, the lasing efficiency is dramatically enhanced. Theoretical analysis using the improved 4x4 transfer matrix and scattering matrix shows that the band edge laser mode can be supported by the external...

Analytical methods are presented for transverse mode analysis of a laser resonator having spherical mirrors with a Gaussian reflectivity profile. The modes of this type of resonator have a form similar to that of the conventional Gaussian modes, but it is necessary to define an additional beam parameter to meet the selfconsistency requirement for resonator modes. Stability of both the conventio...

The discharge quality and optimum pump parameters of a long-pulse high-pressure gas discharge excited KrCl laser are investigated. A three-electrode prepulse–mainpulse excitation circuit is employed as pump source. The discharge volume contains a gas mixture of HCl/Kr/Ne operated at a total pressure of up to 5 bar. For a plane–plane resonator, the divergence of both output laser beams is measur...

Nanowires of the wide band-gap semiconductor gallium nitride (GaN) have been shown to act as room-temperature uv lasers. Recent advances in nanomanipulation have made it possible to modify the shape of these structures from a linear to a pseudoring conformation. Changes to the optical boundary conditions of the lasing cavity affect the structure's photoluminescence, photon confinement, and lasi...

GaAs/GaAlAs heterostructure lasers with a monolithic confocal unstable resonator were demonstrated. The curved mirrors satisfying the confocal condition were fabricated by etching. Close to threshold, the lasers operate in a single lateral mode with a nearly collimated output beam. A single-lobe far-field intensity distribution as narrow as 1.9 degrees full width at half maximum was measured.

Fabrication and properties of an integrated optical ring laser of 60 mm diameter with Ti:Er:LiNbO3 waveguides are reported. Without any intracavity wavelength selective devices the laser emits at λ = 1603 nm. The potential of laser, passive and loss-compensated ring resonator as optical gyroscope is briefly discussed.

An organic semiconductor laser, simply fabricated by UV-nanoimprint lithography (UV-NIL), that is pumped with a pulsed InGaN LED is demonstrated. Molecular weight optimization of the polymer gain medium on a nanoimprinted polymer distributed feedback resonator enables the lowest reported UV-NIL laser threshold density of 770 W cm(-2) , establishing the potential for scalable organic laser fabri...

A compact side-pumped solar laser design using a Ce:Nd:YAG medium is here proposed to improve the TEM00-mode output performance, more specifically beam brightness. The performance of head was numerically studied by both ZEMAX® v13 and LASCADTM v1 software. Maximum multimode power 99.5 W computed for 4.1 mm diameter, 34 length grooved rod, corresponding collection efficiency 33.2 W/m2. To extrac...

This is a continuation of our previous work [Opt. Express 16, 9155 (2008)]. In this paper we investigate the effect of nonuniform pumping on the modal properties of surface-emitting chirped circular grating lasers. By numerically solving the coupled-mode equations and matching the boundaries we compare and discuss the threshold pump levels and frequency detuning factors for three pumping profil...

Fluorescent biosensors have been widely used in biomedical applications. To amplify the intensity of fluorescence signals, this study developed a novel structure for an evanescent wave fiber-optic biosensor by using a Fabry-Perot resonator structure. An excitation light was coupled into the optical fiber through a laser-drilled hole on the proximal end of the resonator. After entering the reson...