Giant lasing effect in magnetic nanoconductors

¹ Department of Microelectronics and Nanoscience, Chalmers University of Technology SE-412 96 Göteborg, Sweden
² Department of Applied Physics, Chalmers University of Technology and Göteborg University - SE-412 96 Göteborg, Sweden
³ Theoretische Physik III, Ruhr-Universität Bochum - D-44780 Bochum, Germany

Corresponding author: kadig@tp3.ruhr-uni-bochum.de

Received: 8 April 2004
Accepted: 27 July 2004

Abstract

We propose a new principle for a compact solid-state laser in the 1–100 regime. This is a frequency range where attempts to fabricate small-size lasers up to now have met severe technical problems. The proposed laser is based on a new mechanism for creating spin-flip processes in ferromagnetic conductors. The mechanism is due to the interaction of light with conduction electrons; the interaction strength, being proportional to the large exchange energy, exceeds the Zeeman interaction by orders of magnitude. On the basis of this interaction, a giant lasing effect is predicted in a system where a population inversion has been created by tunneling injection of spin-polarized electrons from one ferromagnetic conductor to another —the magnetization of the two ferromagnets having different orientations. Using experimental data for ferromagnetic manganese perovskites with nearly 100% spin polarization, we show the laser frequency to be in the range 1–100. The optical gain is estimated to be of order 10⁷, which exceeds the gain of conventional semiconductor lasers by 3 or 4 orders of magnitude. A relevant experimental study is proposed and discussed.