Experimental study of the efficiency of a multi-pass pumping scheme for solar lasers

Here we present the results of our study on the feasibility of a multi-pass pumping scheme in solar lasers. A secondary concentrator has been developed to ensure the multiple passage of solar photons through the active medium. When using a multi-pass pumping scheme, an increase of 12.5% in the luminescence spectra of Nd:YAG is observed in the vicinity of the lasing line at a wavelength of 1064 nm

Поляритонные моды в цилиндрическом микрорезонаторе в режим поляритонного лазера

The spectra of exciton-polariton photoluminescence from cylindrical microcavities under optical excitation below and above the threshold of transition to the polariton laser regime under conditions of strong exciton-photon coupling were studied. At relatively weak optical excitation, lateral quantization modes of polaritons and whispering gallery modes appeared. Both the spectral distribution of these modes and the spatial dependence of their wave functions in the resonator plane were observed. With an increase in the excitation intensity and a transition to the polariton laser regime, only one, the longest-wavelength lasing line remained in the spectrum. It has been suggested that under strong optical excitation, the spectrum contains not only exciton-polariton radiation, but also trion-polariton radiation.

Исследование чувствительности микродискового лазера к изменению показателя преломления окружающей среды

We investigated the dependence of the spectral position of the lasing line of a microdisk laser with InAs/InGaAs/GaAs quantum dots on the refractive index of an aqueous solution in which the microlaser is immersed. For microlasers with 10 μm diameter immersed in an aqueous solution of glucose, the maximum resonance shift of 9.4 nm/RIU was obtained.

How Laser Physics Brought Optics to the World of Photonic Crystals

A brief review of authors’ research is presented. An emphasis is made on the photon localization in the helical structure of a chiral liquid crystal (CLC), which was first experimentally registered by the authors. An analysis of the spectral and lasing characteristics of distributed feedback (DF) lasers based on natural CLCs (type 1) and on chiral nematics (type 2) led to a conclusion that the model of photonic crystal is suitable to describe the lasing mechanism in type-2 CLC lasers, but not in type-1 ones. This conclusion is evidenced by the absence of lasing bands at the opposite edges of the selective reflection (SR) band; at the same time, the lasing line is located at its center. It is shown that if the SR band of the CLC overlaps the maximum of the laser dye fluorescence band, the lasing line coincides with the SR band center to an error of ±1 nm. If the layer thickness in the CLC lasers of both types does not exceed 50 мm, when a high-quality planar texture is retained and a low generation threshold is achieved, a significant difference between their optical characteristics takes place. Namely, the SR spectrum for a type-1 CLC laser is approximately described by a Lorentzian profile, whereas the contour of the SR spectrum for a type-2 CLC laser has a profile characteristic of the transmittance through multilayer dielectric mirrors. The origins of the differences between the optical and laser characteristics of the CLC lasers of both types have been analyzed from the viewpoint of two lasing models: DF and photonic-crystal ones.