Hottest semiconductor laser laser diode laser

Semiconductor lasers, laser diodes, lasers

semiconductor lasers, also known as laser diodes, are a class of lasers that use semiconductor materials as working materials to produce stimulated emissions. Commonly used materials are gallium arsenide (GaAs), cadmium sulfide (CDS), indium phosphide (INP), zinc sulfide (ZnS). There are three types of excitation: electric injection, electric stabilizing oil delivery valve sub beam excitation and optical pumping excitation. Semiconductor laser devices can generally be divided into homogeneous junction, single heterojunction and double heterojunction. Homojunction lasers and single heterojunction lasers are mostly pulse devices at room temperature, while double heterojunction lasers can work continuously at room temperature. Semiconductor lasers have the advantages of small size, light weight, reliable operation, low energy consumption, high efficiency, long service life and high-speed modulation. Therefore, semiconductor lasers have been widely used in laser communication, optical storage, optical gyroscope, laser printing, laser medical treatment, laser ranging, laser radar, automatic control, detection instruments and other fields

the working principle of semiconductor lasers is: through certain excitation methods, between the energy bands (conduction band and valence band) of semiconductor substances, or between the energy bands of semiconductor substances and the energy levels of impurities (acceptor or donor), the particle number inversion of non-equilibrium carriers is realized. When a large number of electrons in the state of particle number inversion are combined with holes, stimulated emission will occur. There are three main ways to excite semiconductor lasers: electric injection, electron beam excitation and optical pump excitation. Electric injection semiconductor lasers are generally semiconductor surface junction diodes made of GaAs (gallium arsenide), InAs (indium arsenide), InSb (indium antimonide) and other materials. They are excited by injecting current along the forward bias voltage, and generate stimulated emission in the junction plane region. Electron beam excited semiconductor lasers generally use n-type or p-type semiconductor single crystals (PBS, CDs, Zho, etc.) as working materials, which are excited by external injection of high-energy electron beams. Optically pumped and excited semiconductor lasers generally use n-type or p-type semiconductor single crystals (GaAs, InAs, InSb, etc.) as working materials, and the laser emitted by other lasers is optically pumped

at present, it accounts for 13.9% in semiconductor lasers; Among the equipment with a stroke of 500 ~ 900mm, the electrical injection GaAs diode semiconductor laser with double heterostructure has better performance and wider application

the working wavelength of semiconductor optoelectronic devices is related to the type of semiconductor materials. There are conduction bands and valence bands in semiconductor materials. Electrons can move freely above the conduction band, while holes can move freely below the valence band. There is a forbidden band between the conduction band and the valence band. When electrons absorb the energy of light and jump from the valence band to the conduction band, the energy of light becomes electricity, and electrons with electric energy jump back from the conduction band to the valence band, which can turn the energy of electricity into light, At this time, the width of the forbidden band of the material determines the working wavelength of the photoelectric device

low power semiconductor lasers (information lasers) are mainly used in the field of information technology, such as distributed feedback and dynamic single-mode lasers (DFB-LD) for optical fiber communication and optical switching systems, narrow linewidth tunable lasers, visible wavelength lasers (405nm, 532nm, 635nm, 650nm, 670nm) for optical disk and other information processing fields. The characteristics of these devices are: single frequency narrow linewidth, high rate, tunable, short wave length, photoelectric monolithic integration, etc

or realize the computer screen display of wear spots of friction pairs. High power semiconductor lasers (power lasers) are mainly used in pump sources, laser processing systems, printing industry, biomedicine and other fields

main parameters of semiconductor laser:

wavelength nm: laser operating wavelength, such as 405nm, 532nm, 635nm, 650nm, 670nm, 690nm, 780nm, 810nm, 860nm, 980nm

threshold current ith: the current at which the laser diode begins to produce laser oscillation, which is about tens of milliamps for low-power lasers

working current IOP: the driving current when the laser diode reaches the rated output power. This value is important for designing and debugging the laser driving circuit

vertical divergence angle θ ⊥: the angle at which the light-emitting band of the laser diode opens perpendicular to the PN junction is generally about 15 ~ 40

horizontal divergence angle θ ∥: the angle of the light-emitting band of the laser diode opening in the direction parallel to the PN junction is generally about 6 ~ 10

monitoring current Im: the current flowing on the pin tube when the laser diode is at the rated output power

semiconductor lasers mainly develop in two directions: one is information lasers that mainly transmit information; The other is the power laser which mainly improves the optical power. Driven by applications such as pumped solid-state lasers, high-power semiconductor lasers have made breakthrough progress, which is marked by a significant increase in the output power of semiconductor lasers. Foreign kW high-power semiconductor lasers have been commercialized, and the output of domestic sample devices has reached 600W. In the future, the development trend of semiconductor lasers is mainly in high-speed wide lasers, high-power lasers, short wavelength lasers, mid infrared lasers and so on. (end)