Semiconductor optical gain

About: Semiconductor optical gain is a research topic. Over the lifetime, 5997 publications have been published within this topic receiving 96505 citations.

Gain in quantum cascade lasers and superlattices: A quantum transport theory

Abstract: Gain in current-driven semiconductor heterostructure devices is calculated within the theory of nonequilibrium Green functions. In order to treat the nonequilibrium distribution self-consistently the full two-time structure of the theory is employed without relying on any sort of Kadanoff-Baym ansatz. The results are independent of the choice of the electromagnetic field if the variation of the self-energy is taken into account. Excellent quantitative agreement is obtained with the experimental gain spectrum of a quantum cascade laser. Calculations for semiconductor superlattices show that the simple two-time miniband transport model gives reliable results for large miniband widths at room temperature.

Dynamic behaviour of semiconductor lasers

Abstract: It will be shown that spontaneous emission in a semiconductor injection laser has an important effect on the response of the laser to a step current. Simple analytical approximations of the description of the transient response, also useful for the study of the response to other current waveforms, are derived.

Theory and optimization of lens ducts

Abstract: Lens ducts are simple optical devices that have found application in the coupling of pump radiation from extended two-dimensional semiconductor laser diode arrays into solid-state laser gain media. The operation of these devices relies on the combined effects of lensing at their curved input surface and channeling by total internal reflection off their canted planar sides, to contain and couple semiconductor diode laser light efficiently to the input face of a solid-state laser crystal or glass. The lens duct provides a robust method for amplifying the irradiance of laser diode array pump sources and has made possible a scalable diode end-pumping architecture that offers the opportunity to expand significantly the number of ions and transitions that can be practically engaged in diode-pumped solid-state laser systems. An analytic model that describes the transfer efficiency of lens ducts and aids in the optimization of their design is presented.

Long-wavelength (≈15.5 μm) unipolar semiconductor laser in GaAs quantum wells

Abstract: A unipolar semiconductor laser emitting in the mid-infrared spectral region is demonstrated. The laser scheme relies on a simple three-level system in GaAs/AlGaAs asymmetric coupled quantum wells. Population inversion between excited states is achieved by optical pumping of electrons from the ground state with a CO2 laser. Long-wavelength (≈15.5 μm) laser emission is demonstrated. The laser is operated in the pulsed regime up to a temperature of 110 K and with an output peak power ≈0.4 W at 77 K. Unipolar quantum well semiconductor lasers based on this principle are capable of covering the long wavelength mid-infrared spectral region above 12 μm.

Gain amplification and lasing properties of individual organic nanofibers

Abstract: We study gain and lasing processes in individual self-assembled organic nanofibers grown on mica substrates. The gain-induced response of the nanofibers is found to depend sensitively on the fiber structure. In homogeneous fibers where no coherent optical feedback is present, high net optical gain (of up to 103cm−1) results in spectral narrowing at the material gain peaks. In the case of strong optical feedback, which occurs in long nanofibers with randomly distributed scattering centers, gain is in turn responsible for low-threshold coherent random laser action.