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This is the simplest of the quantum cascade lasers. An optical waveguide is first fabricated out of the quantum cascade material to form the gain medium. The ends of the crystalline semiconductor device are then cleaved to form two parallel mirrors on either end of the waveguide, thus forming a Fabry–Pérot resonator. The residual ...
A Quantum Cascade Detector (QCD) is a photodetector sensitive to infrared radiation. [2] The absorption of incident light is mediated by intersubband transitions in a semiconductor multiple-quantum-well structure. The term cascade refers to the characteristic path of the electrons inside the material bandstructure, induced by absorption of ...
Laser types with distinct laser lines are shown above the wavelength bar, while below are shown lasers that can emit in a wavelength range. The height of the lines and bars gives an indication of the maximal power/pulse energy commercially available, while the color codifies the type of laser material (see the figure description for details).
A distributed-feedback laser (DFB) is a type of laser diode, quantum-cascade laser or optical-fiber laser where the active region of the device contains a periodically structured element or diffraction grating. The structure builds a one-dimensional interference grating (Bragg scattering), and the grating provides optical feedback for the laser.
The efficiency of a quantum well laser is greater than that of a bulk laser because the density of states function of electrons in the quantum well system has an abrupt edge that concentrates electrons in energy states that contribute to laser action. Lasers containing more than one quantum well layer are known as multiple quantum well lasers.
In a standard multiple quantum well laser, the active quantum wells used to generate photons are connected in parallel. Consequently, a large current is required to replenish each active well with electrons as it emits light. In a cascade laser, the wells are connected in series, meaning that the voltage is higher but the current is lower.
Schematic diagram of a typical laser, showing the three major parts. A laser is constructed from three principal parts: An energy source (usually referred to as the pump or pump source), A gain medium or laser medium, and; Two or more mirrors that form an optical resonator.
A frequency comb or spectral comb is a spectrum made of discrete and regularly spaced spectral lines.In optics, a frequency comb can be generated by certain laser sources.. A number of mechanisms exist for obtaining an optical frequency comb, including periodic modulation (in amplitude and/or phase) of a continuous-wave laser, four-wave mixing in nonlinear media, or stabilization of the pulse ...