Amplification of Laser Emission from Cholesteric Liquid Crystals by Planar Cells with Laser Dye Nematic and Isotropic Solutions

Abstract

A possibility have been shown for amplification of weak emission intensity of microlasers based on cholesteric liquid crystals (CLC) by thin planar layers of both isotropic dye solutions and dye doped nematic liquid crystals. Very high gain index values (up to 500 cm⁻¹) and absolute amplification of about 15 have been demonstrated. Especially important is the anisotropy of gain in nematics, which allows the field control of the light amplification by an electric field. The planar amplifiers using nematic liquid crystals can easily be integrated within single planar devices together with distributed feedback CLC microlasers. In such a hybrid structure, 6-times amplification of CLC microlaser intensity has been achieved.

Keywords:

• dye lasers
• laser amplifiers
• liquid crystals

Acknowledgments

The authors thank Mr. S. V. Yakovlev (ICRAN) and Mr. A. Pane (LiCryL-CNR) for the help in experiment and Prof. E. A. Luk'yanets and Dr. V. I. Alekseeva for supplying the samples of dye Chromene-3. The Russian group was supported by OFN RAN (program “Laser systems based on novel active materials”). The Italian group acknowledges the support from CNR-INFM and the CEMIF.CAL funds.