Electronic control of nonresonant random lasing from a dye-doped smectic A liquid crystal scattering device

The electronic control of the excitation threshold for random lasing in a dye-doped smectic A * liquid crystal is demonstrated. Random lasing is the term given to the nonlinear amplification of light which is the result of feedback due to multiple scattering. With the application of an electric field the smectic A * phase forms a highly scattering texture for which the nonlinear amplification of light occurs at an excitation threshold of 10 μ J ∕ pulse . In comparison, nonlinear amplification is not observed in the field induced homeotropic texture. As a result, a device has been conceived and demonstrated whereby random lasing is switched "on" or "off" with an applied electric field.