LEDs (Lub Teeb Emitting Diodes) thiab Lasers (Lub Teeb Amplification los ntawm Stimulated Emission of Radiation) yog ob qho ntawm cov khoom siv photonics uas siv dav hauv ntau yam kev siv xws li teeb pom kev zoo, cov ntaub ntawv sib txuas lus, kev kho mob, thiab kev ua tub rog. Txawm hais tias ob qho tib si LED thiab laser li tsim lub teeb, lawv muaj cov qauv sib txawv thiab cov txheej txheem ntawm lub teeb emissions. Hauv tsab xov xwm no, peb yuav tham txog qhov sib txawv ntawm LED thiab laser qauv.
1. LED Structure
LEDs feem ntau yog ua los ntawm cov khoom siv semiconductor xws li gallium arsenide (GaAs) lossis gallium nitride (GaN). Lawv yog tsim los ntawm pn hlws ris, qhov twg electrons thiab qhov sib txuas thiab tso tawm lub zog nyob rau hauv daim ntawv ntawm lub teeb photons. LEDs tuaj yeem muab faib ua ob hom: ncaj qha bandgap thiab indirect bandgap. Direct bandgap LEDs emit teeb ncaj qha los ntawm recombination ntawm electrons thiab qhov, thaum indirect bandgap LEDs yuav tsum tau kev pab los ntawm ib tug nyob ze crystal defect kom emit lub teeb. LEDs feem ntau yog cov khoom siv hluav taws xob qis thiab tuaj yeem tawm lub teeb hauv ntau xim, suav nrog liab, ntsuab, xiav, thiab dawb.
2. Laser qauv
Lasers, ntawm qhov tod tes, yog tsim los ntawm peb lub hauv paus ntsiab lus: ib qho nruab nrab active, ib qhov chaw siv, thiab ib tug resonant kab noj hniav. Lub active nruab nrab yog cov khoom muaj peev xwm ntawm amplifying lub teeb los ntawm stimulated emission. Lub twj tso kua mis muab lub zog los ua kom cov atoms lossis molecules hauv qhov nruab nrab nquag mus rau qib siab dua. Lub resonant kab noj hniav muab tswv yim los nthuav lub teeb emitted los ntawm lub active nruab nrab. Cov qauv laser tuaj yeem muab faib ua ob hom tseem ceeb: ntug-emitting thiab nto-emitting. Ntug-emitting lasers emit lub teeb los ntawm ntug ntawm lub cuab yeej, thaum nto-emitting lasers emit lub teeb los ntawm qhov chaw.
3. Qhov txawv ntawm LED thiab Laser Structures
Qhov sib txawv tseem ceeb ntawm LED thiab cov qauv laser nyob hauv lawv txoj haujlwm ua haujlwm. LEDs emit lub teeb thaum electrons recombine nrog lub qhov, thiab lub teeb yog spontaneously emitted nyob rau hauv tag nrho cov kev taw qhia. Nyob rau hauv sib piv, lasers emit lub teeb thaum zoo siab atoms los yog molecules nyob rau hauv lub active nruab nrab emit photons uas txhawb lwm yam atoms los yog molecules kom emit ntau photons, uas ua rau ib coherent beam ntawm lub teeb. Lub coherent thiab directional xwm ntawm laser teeb tso cai rau nws mus deb npaum li cas tshaj LED teeb.
Lwm qhov sib txawv yog qhov nyuaj ntawm cov qauv. Thaum cov qauv LED feem ntau yooj yim dua thiab xav tau lub zog tsawg dua, cov qauv laser ntau dua thiab xav tau lub zog ntau dua los ua haujlwm. Qhov no yog vim hais tias lasers xav tau ib tug resonant kab noj hniav los tsim cov tswv yim tsim nyog rau coherent lub teeb emission, whereas LEDs tsis.
Hauv cov ntsiab lus, LEDs thiab lasers yog cov khoom siv photonics sib txawv nrog cov qauv sib txawv thiab cov txheej txheem ntawm lub teeb emissions. LEDs emit lub teeb los ntawm pn hlws ris thaum electrons thiab qhov recombine, thaum lasers emit coherent thiab directional teeb los ntawm stimulated emission nyob rau hauv ib tug active nruab nrab nyob rau hauv ib tug resonant kab noj hniav. Ob lub cuab yeej muaj cov ntawv thov sib txawv thiab qhov zoo nyob ntawm qhov kev xav tau tshwj xeeb ntawm lub kaw lus.
