Intervalence band absorption and carrier heating in type-II Sb-based lasers

Abstract

Pnhlir rsnortina burden for this collection of information is estimated lo average 1 hour per response, including the time (or reviewing instructions, searching existing data sources gathering and maintaining fhdatmeeded anc?S^^art r^«*«Mi collection of information Send comments regarding this burden estimate or any other aspect of this collects of information including s"99^°ns or edudnowsburdentTDepalent of Defense Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway Suite 1204, Arl.n9.onyA 2220Ä Respondent sS be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information ,f,. does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) PERFORMING ORGANIZATION REPORT NUMBER SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)AFRL/DELS 3550 Aberdeen Ave SE Kirtland AFB NM 87117-5776 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) SUPPLEMENTARY NOTESJournal article accomplished for two different efforts listed in Blocks 5c thru 5f above.14. ABSTRACT , . ,The intervalence absorption in InAs/InGaSb/InAs type-II 4um quantum well laser structure was investigated using band-edge nonlinear pump-probe spectroscopy techniques where two pump beams chopped at different frequencies are used to excite the sample. The spectrally resolved probe nonlinearity is measured at the sum frequency. Given their different characteristic nonlinearities, the contribution of the intervalence absorption process (IVA) was resolved from that of the interband gain dynamics. The IVA absorption occurs at in-plane momentum kl 1-0.025 Vand is not resonant with the interband lasing energy, therefore does not compete with the interband transition at low temperature and low carrier densities. A density dependent interband transition matrix element of N was deduced reflecting the enhancement of the electron hole wavefunction overlap due to the space-charge fields in the type-II wells. Significant lattice heating observed above 80K is reflected in the growth of an out of phase slow signal, resulting from the reduction of lattice thermal conductivity and the IVA resonance enhanced nonradiative Auger recombination transitions at higher temperatures. Thermal diffusion times of the order of-100 us that increases with temperature were measured. The intervalence absorption in InAs/InGaSb/InAs type-II 4 jum quantum well laser structure was investigated using band-edge nonlinear pump-probe spectroscopy techniques where two pump beams chopped at different frequencies are used to excite the sample. The spectrally resolved probe nonlinearity is measured at the sum frequency. Given their different characteristic nonlinearities, the contribution of the intervalence absorption process (IVA) was resolved from that of the i...

Extraction of radiative and nonradiative rates in Sb based midwave infrared lasers using a novel approach

“…6 This problem of correlations can be avoided by time resolving the nonlinearity of the PL upconversion signal in a nonlinear crystal, in a similar fashion to time resolving the nonlinearity of pump-probe measurements. 16,17 However, it is desirable to avoid dealing with measurements involving several meters of mechanical delay for resolving nanosecond dynamics. Even in the presence of adequate fast detectors that would alleviate the problem of mechanical delay stages, the radiative and nonradiative rates cannot be resolved.…”