Quantum LasersOverview1. Quantum LasersSingle-Quantum Well Laser (SQWL)Refractive Index and Mode ProfileMultiple-Quantum Well Laser (MQWL)Separate Confinement Heterostructure (SCH)Graded-Index SCH Laser (GRINSCH L)Quantum Cascade Laser (QC L) — PrincipleQC Laser — -TailoringQC Laser — DataQuantum Dot Lasers (QD L) — 1. PrincipleQD L — 2. Principle2. SummaryWhat we left out… (more presentations?)3. References (QC L)4. References (QD L)History of LasersWhere to find papers……Wanna BUY a quantum laser?1. Example: Quantum Cascade Laser2. Example: Single-Mode SQW GRINSCH LPricelist (all in US Dollars)Abbreviations (Alphabetical Order)For those who want to know more…Quantum Lasers,M. Momeni1Quantum LasersEE 566 Optical CommunicationsMassoud MOMENIGrad [email protected] Lasers,M. Momeni2Overview1. Quantum Lasers Q La) Single-Quantum Well Laser SQW Lb) Multiple-Quantum Well Laser MQW Lc) Separate Confinement Heterostructure Laser SCH Ld) Graded-Index SCH Laser GRINSCH Le) Quantum Cascade Laser QC Lf) Quantum Dot Laser QD L2. Summary3. References and…Quantum Lasers,M. Momeni31. Quantum LasersLASER = Light Amplification by Stimulated Emission of RadiationQuantum Lasers,M. Momeni4Single-Quantum Well Laser (SQWL)Double Heterostructure:GFpFnEEE )(1)(VVVCEfhfEf or, alternatively,Basic Laser condition:nmhfV > 0P p NEVECEFpEFnEelEholeQuantum Lasers,M. Momeni5Refractive Index and Mode Profilep+n+P p n+P p NHomostructure Single Heterostructure (SHS) Double Heterostructure (DHS)noptical fieldOptical confinement is higher for a DHSElectrical confinement is higher for a DHS lower IthQuantum Lasers,M. Momeni6Multiple-Quantum Well Laser (MQWL)P p PEVECMQW using isotype SQW:mini bandsP p P p P p P p Phf hf hf hfMQW DFBMQW DFBQuantum Lasers,M. Momeni7Separate Confinement Heterostructure (SCH)hfEVxP p NECInPInGaAsPInGaAsPInPInGaAsPInGaAsMQW regionSCH region SCH regioncladding cladding5 nm10 nm50 nmQuantum Lasers,M. Momeni8ECEG ( InP )Graded-Index SCH Laser (GRINSCH L)EG ( InGaAsP )EG ( InGaAs )EVGRIN regionGRIN region MQW regionncladding claddingxQuantum Lasers,M. Momeni9Quantum Cascade Laser (QC L) — Principleinterband transition:intersubband transition:EapplTunneling rate >> 3 = 1 psand 2 = 0.3 ps << 32 > 1 ps  population inversionQuantum Lasers,M. Momeni10QC Laser — -TailoringQuantum Lasers,M. Momeni11QC Laser — DataData [1–5]:Applications [1–6]:•Military and Security•Commercial, Medical•Free-Space Optical Communication Systems and Astronomy•Gas detection based on laser spectroscopy with CW or pulsed QC DFB lasers (chemical sensors)L[m]Pout[mW]Jth [A/cm2] /Eth [kV/cm]operation modeTfirst demo[year]$$$3.4 – 80 200 – 300 (CW) up to 1000 (PM)250 – 290 /7.5 – 48PM or CW on cooler350 1994 AT&T Bell Labs(later)Material systems: GaAs based, InP based, Si / SiGe on GaSb, InAs / AlSb on GaSbCW = continuous wave; PM = pulse modeQuantum Lasers,M. Momeni12Quantum Dot Lasers (QD L) — 1. Principleb) tunneling-injection QD laser:a) schematic view:Quantum Lasers,M. Momeni13QD L — 2. Principlea) Prevention of parasitic b) “Limit case” recombination in the OCLn-claddingp-claddingOCLOCLQDelectronsholesQuantum Lasers,M. Momeni142. SummaryQuantum Lasers use the structures we have discussed so far in order to1. optimize the properties of a simple Fabry-Perot Laser (L, R, g, ),2. Increase efficiency ()3. reduce the threshold current (Ith) and its temperature dependency,4. change the wavelength of the laser beam ( ),5. achieve continuous wave (CW) operation @ RT, and6. increase the output power (P).Fabrication:1. Metallorganic chemical vapor deposition MOCVD2. Molecular beam epitaxy MBEQuantum Lasers,M. Momeni15What we left out… (more presentations?)Basics:oQuantum Effects (energy quantization, first and second order tunneling effect,…)oSimple Fabry Perot Laser (FPL) and characteristicsoConcept of gain-guided (active) or index-guided (passive) lasers (wave guiding), e.g. in buried heterostructure lasers (BHS), or separate lateral confinement (LC)oDistributed bragg reflector (DBR), distributed feedback bragg (reflector) (DFB)R&D:-Blue Lasers or GaN Lasers-Tunable Lasers (TL) or Tunable Diode Lasers (TDL)-Vertical Cavity Surface Emitting Lasers (VCSEL)-Strained heterostructure QW lasersQuantum Lasers,M. Momeni163. References (QC L)[1] Sirtori C., Nagle J., “Quantum Cascade Lasers: the quantum technology for semiconductor lasers in the mid-far-infrared.” Comptes Rendus Physique, In Press, Corrected Proof, Sep. 2003http://www.sciencedirect.com/science/article/B6X19-49FGMWM-6/2/299ee308e587b6215f4731fbe5cfd566[2] Garciaa M., Normand E., Stanley C.R., Ironside C.N., Farmer C.D., Duxbury G., Langford N., "An AlGaAs–GaAs quantum cascade laser operating with a thermoelectric cooler for spectroscopy of NH3.“ Optics Communications, In Press, Uncorrected Proof, Sep. 2003.http://www.sciencedirect.com/science/article/B6TVF-49FXMFB-3/2/607fb52178f815aca3c266c7cf670524[3] Köhler, R., Tredicucci A., Beltram F., Beere H.E., Linfield E.H., Davies A.G., Ritchie D.A., Iotti, R.C., Rossi F., "Terahertz semiconductor-heterostructure laser" letters to nature, vol. 417 no. 6885, pp. 156–159, May 2002.[4] Sirtori C., "Applied physics: Bridge for the terahertz gap." Nature news and views, vol. 417, no. 6885, pp. 132–133, May 2002.[5] Beck M., Hofstetter D., Aellen T., Faist J., Oesterle U., Ilegems M., Gini E., Melchior H., “Continuous wave operation of a mid-infrared semiconductor laser at room temperature.” Science, vol. 295, issue 5553, pp. 301–305, Jan. 2002. [6] Kosterev A.A., Tittel F.K., "Chemical Sensors Based on Quantum Cascade Lasers." IEEE Journal of Quantum Electronics, vol. 38, no. 6, , pp. 582–591, June 2002.Quantum Lasers,M. Momeni174. References (QD L)[7] Asryan L.V., Luryi S., "Tunneling-Injection Quantum-Dot Laser: Ultrahigh Temperature Stability" IEEE Journal of Quantum Electronics, vol. 37, no. 7, pp. 905–910, July 2001.http://www.ee.sunysb.edu/~serge/177.pdf http://www.ee.sunysb.edu/~serge/publist.pdf[8] Asryan L.V., Luryi S., Suris R.A., "Internal Efficiency of Semiconductor Lasers With a Quantum-Confined Active Region." IEEE Journal of Quantum Electronics, vol. 39, no. 3, pp. 404–418, March 2003.http://www.ee.sunysb.edu/~serge/191.pdf[9] Pelton M., Yamamoto Y., "Ultralow