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Above threshold, the slope of power vs. excitation is orders of magnitude greater. The linewidth of the laser's emission also becomes orders of magnitude smaller above the threshold than it is below. Above the threshold, the laser is said to be lasing. The term "lasing" is a back formation from "laser," which is an acronym, not an agent noun.
The laser diode rate equations model the electrical and optical performance of a laser diode. This system of ordinary differential equations relates the number or density of photons and charge carriers in the device to the injection current and to device and material parameters such as carrier lifetime, photon lifetime, and the optical gain.
The laser diode chip removed and placed on the eye of a needle for scale A laser diode with the case cut away. The laser diode chip is the small black chip at the front; a photodiode at the back is used to control output power. SEM (scanning electron microscope) image of a commercial laser diode with its case and window cut away. The anode ...
Semiconductor lasers or laser diodes play an important part in our everyday lives by providing cheap and compact-size lasers. They consist of complex multi-layer structures requiring nanometer scale accuracy and an elaborate design. Their theoretical description is important not only from a fundamental point of view, but also in order to ...
Diagram of a simple VCSEL structure. The vertical-cavity surface-emitting laser (VCSEL / ˈ v ɪ k s əl /) is a type of semiconductor laser diode with laser beam emission perpendicular from the top surface, contrary to conventional edge-emitting semiconductor lasers (also called in-plane lasers) which emit from surfaces formed by cleaving the individual chip out of a wafer.
The original 1975 demonstration of optically pumped quantum-well lasers had threshold power density of 35 kW/cm 2. Ultimately, it was found that the lowest practical threshold current density in any quantum-well laser is 40 Amperes/cm 2, a reduction of approximately 1,000x. [10] [full citation needed]
2005-11-19 06:18 The Photon 283×283×0 (35473 bytes) Diagram of a simple laser diode. ... Diagram of a simple (current-confined, homojunction) laser diode.
If the injection current is rapidly switched off at the proper time, for example using a step recovery diode circuit, a single 50 ps light pulse can be generated. For solid-state and dye lasers, gain switching (or synchronous pumping) usually involves the laser gain medium being pumped with another pulsed laser. Since the pump pulses are of ...