Tunable stimulated spin‐flip raman scattering in InSb at various wavelengths

Abstract

Tunable stimulated spin-flip Raman scattering from ponduetion electrons in InSb is investigated a t four different pump wavelengths (10.6, 10.2, 5.3, 5.1 pm). The tunable frequency range of the Raman-scattered radiation is increased. Output powers of the Raman-scattered light as a function of input power densities and magnetic fields were measured for the mentioned pump wavelengths. Thresholds for stimulated scattering were determined. From these the gain factors were calculated. The expected resonance in the 5 ym region is seen in the results and leads to extremely low thresholds and high gain factors.Abstimmbare stimulierte Spin-Flip-Raman-Streuung an Leitungselektronen in InSb wird fur vier verschiedene PumpwellenlLngen (10,6; 10,2; 5,3; 5,l pm) untersucht. Iladurch wird der Frequenzbereich der gestreutcn Strahlung erwcitert. Die Leistungen in den Raman-Linien wurden als Funktion der l'urnpleistungsdichten und des Magnetfeldes fur die genannten PiimpwellenlLngen gemessen und die Schwellen fur das Einsetzen stimulierter Streuung best,immt,. Die daraus berechneten Verstarkungsfaktoren werden angegeben. I n den Ergebnissen zeigt sieh die erwartete Resonanz ini 5 pin-Bereich, die sich in extrem niedrigen Schwellwerten und hohen Verstarknngsfaktoren luBert. . I n all these cases the pump power was supplied by a 10.6 pm CO, laser. First Stokes, first antiStokes [5 to 71, and second Stokes [ 5 ] emission were found to cover a considerable spectral range in the near infrared region with narrow linewidths. Int#rodiictionPumping with 5.3 pm resonantly enhances the spin-flip scattering cross-section [S to 101, leading to the lowest t,hreshold powers in stimulated Raman scattering observed up to now [9].I n this paper we present results of systematic investigations in both wavelength regions under similar cxpcriment,al conditions. We can directly compare SFR data obtained by pumping with four different wavelengths, i.c. 10.6, 10.2, 5.3, and 5.1 pm. Thus we increased the tuning range of SFR and obtained further information about SER pumped resonantly with energies nea.r to the Present addresses :