Laser diodes optical gain

Characteristics of fluoride glass optical amplifiers. All fibers are ZBLAN-based glass except when otherwise indicated. (LD) laser diode ( ) gain obtained with two amplification units. 

The broad spectral coverage for luminescence from the ultraviolet (UV) to the NIR offered via the tunability of composition, size and shape in semiconductor nanocrystals, presents an obvious advantage for the use of such materials as tunable optical gain media, and in laser applications. Furthermore, low lasing thresholds are predicted for QDs and quantum wires, compared with two-dimensionally confined quantum wells, form the basis of the present semiconductor diode laser devices which are ubiquitous in information and telecommunication technologies [86, 87]. 

In a simple DH-diode laser device, as outlined above, no mechanism to select a particular wavelength is provided other than altering the length of the resonator itself. In addition, semiconductor diode laser materials exhibit optical gain over a fairly... 

The future prospects for selective chemistry research as an aspect of laser development are not as bright as several years ago. With the exception of the quest for a visible chemical laser, most new laser research is oriented towards systems that are patently nonmolecular. The leading candidate for very high power applications is the free electron laser (PEL). In this device, the interaction of a relativistic electron beam with a periodic magnetic structure produces coherent radiation. Such devices on paper can have substantially higher power and efficiency than electric molecular lasers. For moderate power applications, advances in solid state lasers, nonlinear optical conversion processes, and tunable solid state media offer the prospect of broadly tunable compact sources. At low powers, diode lasers and diode laser arrays are gaining increasing application and hold out the promise, when used with solid state media, of versatile tunable sources. 

The measurements have to be repeated at increasing pump powers, in order to draw a curve indicating the pump power where transparency (G = 0 dB/cm) and saturation of the gain are obtained. It can be also necessary to measure the optical gain at several wavelengths, in order to define what is the operational amplification bandwidth in that case, a tunable signal laser source (typically, a laser diode with external cavity) has to be used. 

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