Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037585
D. Citrin, A. Maslov
The modulation of the optical properties of semiconductor quantum wells at THz frequencies is explored theoretically. The modulation occurs via coherent optical/THz mixing since the modulation frequency can well exceed the optical dephasing rate.
{"title":"Terahertz/optical properties of semiconductor quantum wells","authors":"D. Citrin, A. Maslov","doi":"10.1109/THZ.2002.1037585","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037585","url":null,"abstract":"The modulation of the optical properties of semiconductor quantum wells at THz frequencies is explored theoretically. The modulation occurs via coherent optical/THz mixing since the modulation frequency can well exceed the optical dephasing rate.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"30 Suppl 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125658083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037591
J. Darmo, T. Muller, G. Strasser, K. Unterraner, T. Le, G. Tempea, A. Stingl
A photoconductive terahertz generator with an integrated Bragg mirror is presented. The generator exhibits significantly improved performance. We demonstrate for the first time intra-cavity THz generation using this type of photoconductive emitter.
{"title":"Intra- and extra-cavity THz generation from optically and electrically confined photoconducting layers [GaAs]","authors":"J. Darmo, T. Muller, G. Strasser, K. Unterraner, T. Le, G. Tempea, A. Stingl","doi":"10.1109/THZ.2002.1037591","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037591","url":null,"abstract":"A photoconductive terahertz generator with an integrated Bragg mirror is presented. The generator exhibits significantly improved performance. We demonstrate for the first time intra-cavity THz generation using this type of photoconductive emitter.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"446 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116020877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037584
T. Muller, R. Bratschitsch, W. Parz, G. Strasser, K. Unterrainer
Presents time-resolved measurements of photoinduced intersubband absorption in an undoped GaAs/AlGaAs coupled quantum well excited by an ultrashort interband optical pulse. An interband pump pulse injects electrons into the first and second subband of an undoped asymmetric double quantum well (ADQW) with a level spacing smaller than the LO phonon energy. The time evolution of the electron population in these two subbands is monitored by probing the MIR intersubband transitions to a third (empty) subband.
{"title":"Coherent and incoherent intersubband dynamics","authors":"T. Muller, R. Bratschitsch, W. Parz, G. Strasser, K. Unterrainer","doi":"10.1109/THZ.2002.1037584","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037584","url":null,"abstract":"Presents time-resolved measurements of photoinduced intersubband absorption in an undoped GaAs/AlGaAs coupled quantum well excited by an ultrashort interband optical pulse. An interband pump pulse injects electrons into the first and second subband of an undoped asymmetric double quantum well (ADQW) with a level spacing smaller than the LO phonon energy. The time evolution of the electron population in these two subbands is monitored by probing the MIR intersubband transitions to a third (empty) subband.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121506929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037615
M. Eckardt, A. Schwanhausser, F. Renner, L. Robledo, A. Friedrich, P. Pohl, P. Kiesel, S. Malzer, G. Dohler, D. Driscoll, M. Hanson, A. Gossard
Reports on a new concept for THz photomixers, which are not (as usually) frequency limited by the carrier lifetime in low-temperature-grown GaAs. The concept is based on ballistic electron transport in a periodically doped heterostructure (p-i-n-p-i-n-superlattice) and allows for impedance matching to the attached antenna.
{"title":"Novel concept for THz-photomixer based on periodically doped heterostructures and quasi ballistic transport","authors":"M. Eckardt, A. Schwanhausser, F. Renner, L. Robledo, A. Friedrich, P. Pohl, P. Kiesel, S. Malzer, G. Dohler, D. Driscoll, M. Hanson, A. Gossard","doi":"10.1109/THZ.2002.1037615","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037615","url":null,"abstract":"Reports on a new concept for THz photomixers, which are not (as usually) frequency limited by the carrier lifetime in low-temperature-grown GaAs. The concept is based on ballistic electron transport in a periodically doped heterostructure (p-i-n-p-i-n-superlattice) and allows for impedance matching to the attached antenna.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127653302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037598
T. Klaassen, J. Hovenier, R. Zhukavin, D. M. Gaponova, A. Muravjov, E. Orlova, V. Shastin, S. Pavlov, H. Hubers, H. Riemann, A. V. D. van der Meer
THz stimulated emission of phosphorus and bismuth donors in silicon under resonant intra-center optical pumping by the tunable free electron laser FELIX has been observed at low temperatures. The dependence of the emission on the excitation wavelength and power is reported.
{"title":"The emission spectra of optically pumped Si-based THz lasers","authors":"T. Klaassen, J. Hovenier, R. Zhukavin, D. M. Gaponova, A. Muravjov, E. Orlova, V. Shastin, S. Pavlov, H. Hubers, H. Riemann, A. V. D. van der Meer","doi":"10.1109/THZ.2002.1037598","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037598","url":null,"abstract":"THz stimulated emission of phosphorus and bismuth donors in silicon under resonant intra-center optical pumping by the tunable free electron laser FELIX has been observed at low temperatures. The dependence of the emission on the excitation wavelength and power is reported.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129109297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037604
T. David, S. Arscott, J. Munier, T. Decoopman, T. Akalin, P. Mounaix, X. Mélique, O. Vanbésien, G. Beaudin, D. Lippens
Fully integrated monolithic circuits incorporating InP-based heterostructure barrier varactor (HBV) frequency multipliers have been fabricated via epitaxial lift-off and transfer-substrate techniques onto a quartz substrate. We have obtained a maximum output power of 6 mW at 288 GHz corresponding to an overall efficiency of 6%. In addition we have observed a 45 GHz 3 dB bandwidth centered around 300 GHz for a constant input power of 70 mW. We also report on the design of a multiplier block in a fin line technology making use of smoothly corrugated tapered sections for mode matching and filtering.
{"title":"High performance HBV multipliers monolithically integrated onto a host quartz substrate","authors":"T. David, S. Arscott, J. Munier, T. Decoopman, T. Akalin, P. Mounaix, X. Mélique, O. Vanbésien, G. Beaudin, D. Lippens","doi":"10.1109/THZ.2002.1037604","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037604","url":null,"abstract":"Fully integrated monolithic circuits incorporating InP-based heterostructure barrier varactor (HBV) frequency multipliers have been fabricated via epitaxial lift-off and transfer-substrate techniques onto a quartz substrate. We have obtained a maximum output power of 6 mW at 288 GHz corresponding to an overall efficiency of 6%. In addition we have observed a 45 GHz 3 dB bandwidth centered around 300 GHz for a constant input power of 70 mW. We also report on the design of a multiplier block in a fin line technology making use of smoothly corrugated tapered sections for mode matching and filtering.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115594619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037606
C. Baker, C. Norman, J. Cluff, W. Tribe, B. Cole, E. Linfield, A. Davies, D. D. Arnone, M. Pepper
It has been postulated that terahertz (THz) generation in photoconductive emitters is associated with electric field transients between the electrodes of the device. This is supported by experimental measurements showing enhanced generation with near-anode device excitation. In this work we present a detailed analysis of the dependence of device performance on the position of laser excitation for two designs of photoconductive emitter. These results are compared to new investigations using the technique of electron beam induced current (EBIC) measurements. EBIC gives an alternative means of examining the electric field within a device, and the results are compared for the full range of applied device bias.
{"title":"Electric field dependence of pulsed THz emission from photoconductive antennas","authors":"C. Baker, C. Norman, J. Cluff, W. Tribe, B. Cole, E. Linfield, A. Davies, D. D. Arnone, M. Pepper","doi":"10.1109/THZ.2002.1037606","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037606","url":null,"abstract":"It has been postulated that terahertz (THz) generation in photoconductive emitters is associated with electric field transients between the electrodes of the device. This is supported by experimental measurements showing enhanced generation with near-anode device excitation. In this work we present a detailed analysis of the dependence of device performance on the position of laser excitation for two designs of photoconductive emitter. These results are compared to new investigations using the technique of electron beam induced current (EBIC) measurements. EBIC gives an alternative means of examining the electric field within a device, and the results are compared for the full range of applied device bias.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128175577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037583
A. Leitenstorfer, R. Huber, F. Tauser, A. Brodschelm
We report on a new class of ultrabroadband THz experiments with a time resolution as high as 30 fs. The measurements rely on single-cycle probe transients which are generated via optical rectification of 10 fs near-infrared pulses in a thin GaSe nonlinear crystal. The electric field of these pulses is directly monitored via ultrabroadband electro-optic detection. On a femtosecond time scale, we observe how Coulomb screening and collective scattering build up in an extreme nonequilibrium electron-hole system in GaAs. To this end, we photogenerate a dense carrier plasma within 10 fs and probe the subsequent polarization response of the system with uncertainty-limited resolution by means of ultrabroadband THz spectroscopy. We show, that the intrinsic material becomes conductive instantaneously upon carrier injection, whereas collective effects such as Coulomb screening and plasmon scattering exhibit a delayed onset Thus, the ultrafast formation of dressed quasiparticles is directly monitored for the first time. The time scale for these phenomena is of the order of the inverse plasma frequency. Thereby, our findings support recent quantum kinetic simulations.
{"title":"Femtosecond experiments using single-cycle pulses at 30 THz: the buildup of screening in a photoexcited electron-hole plasma","authors":"A. Leitenstorfer, R. Huber, F. Tauser, A. Brodschelm","doi":"10.1109/THZ.2002.1037583","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037583","url":null,"abstract":"We report on a new class of ultrabroadband THz experiments with a time resolution as high as 30 fs. The measurements rely on single-cycle probe transients which are generated via optical rectification of 10 fs near-infrared pulses in a thin GaSe nonlinear crystal. The electric field of these pulses is directly monitored via ultrabroadband electro-optic detection. On a femtosecond time scale, we observe how Coulomb screening and collective scattering build up in an extreme nonequilibrium electron-hole system in GaAs. To this end, we photogenerate a dense carrier plasma within 10 fs and probe the subsequent polarization response of the system with uncertainty-limited resolution by means of ultrabroadband THz spectroscopy. We show, that the intrinsic material becomes conductive instantaneously upon carrier injection, whereas collective effects such as Coulomb screening and plasmon scattering exhibit a delayed onset Thus, the ultrafast formation of dressed quasiparticles is directly monitored for the first time. The time scale for these phenomena is of the order of the inverse plasma frequency. Thereby, our findings support recent quantum kinetic simulations.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114293687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037602
S. Barbieri, J. Alton, M. Evans, S. Dhillon, H. Beere, E. Linfield, A. Davies, D. Ritchie, R. Kohler, A. Tredicucci, F. Beltram
Reports continuous wave operation of a 4.4 THz unipolar injection quantum cascade laser grown in the AlGaAs/GaAs materials system by molecular beam epitaxy. The device operates at 4 K with a threshold current of 160 mA, and an output power of /spl sim/25 /spl mu/W. In pulsed mode the maximum operating temperature is 52 K with a threshold current of 108 mA at 4 K.
{"title":"Continuous wave terahertz quantum cascade laser","authors":"S. Barbieri, J. Alton, M. Evans, S. Dhillon, H. Beere, E. Linfield, A. Davies, D. Ritchie, R. Kohler, A. Tredicucci, F. Beltram","doi":"10.1109/THZ.2002.1037602","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037602","url":null,"abstract":"Reports continuous wave operation of a 4.4 THz unipolar injection quantum cascade laser grown in the AlGaAs/GaAs materials system by molecular beam epitaxy. The device operates at 4 K with a threshold current of 160 mA, and an output power of /spl sim/25 /spl mu/W. In pulsed mode the maximum operating temperature is 52 K with a threshold current of 108 mA at 4 K.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125700730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/THZ.2002.1037599
S. Pavlov, H. Hubers, R. Zhukavin, E. Orlova, H. Riemann, V. Shastin
Photoexcitation of shallow impurity centers in silicon at low temperatures (<10 K) yields stimulated emission from intra-center optical transitions in the terahertz range. The population inversion mechanisms are based on the peculiarities of electron-phonon interaction, leading to the existence of either a relatively long-living excited impurity state or a group of unpopulated impurity states.
{"title":"Optically pumped terahertz silicon lasers","authors":"S. Pavlov, H. Hubers, R. Zhukavin, E. Orlova, H. Riemann, V. Shastin","doi":"10.1109/THZ.2002.1037599","DOIUrl":"https://doi.org/10.1109/THZ.2002.1037599","url":null,"abstract":"Photoexcitation of shallow impurity centers in silicon at low temperatures (<10 K) yields stimulated emission from intra-center optical transitions in the terahertz range. The population inversion mechanisms are based on the peculiarities of electron-phonon interaction, leading to the existence of either a relatively long-living excited impurity state or a group of unpopulated impurity states.","PeriodicalId":143116,"journal":{"name":"Proceedings, IEEE Tenth International Conference on Terahertz Electronics","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129708746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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