Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers
Recent research has shown that free-running quantum cascade lasers are capable of producing frequency combs in midinfrared and THz regions of the spectrum. Unlike familiar frequency combs originating from mode-locked lasers, these do not require any additional optical elements inside the cavity and...
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| Format: | Article |
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SPIE
2018
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| Online Access: | http://hdl.handle.net/1721.1/115419 https://orcid.org/0000-0001-5848-2389 https://orcid.org/0000-0003-1982-4053 |
| _version_ | 1826212428606603264 |
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| author | Henry, Nathan Khurgin, Jacob B. Burghoff, David Patrick Yang, Yang Hu, Qing |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Henry, Nathan Khurgin, Jacob B. Burghoff, David Patrick Yang, Yang Hu, Qing |
| author_sort | Henry, Nathan |
| collection | MIT |
| description | Recent research has shown that free-running quantum cascade lasers are capable of producing frequency combs in midinfrared and THz regions of the spectrum. Unlike familiar frequency combs originating from mode-locked lasers, these do not require any additional optical elements inside the cavity and have temporal characteristics that are dramatically different from the periodic pulse train of conventional combs. Frequency combs from quantum cascade lasers are characterized by the absence of sharp pulses and strong frequency modulation, periodic with the cavity round trip time but lacking any periodicity within that period. To explicate for this seemingly perplexing behavior, we develop a model of the gain medium using optical Bloch equations that account for hole burning in spectral, spatial, and temporal domains. With this model, we confirm that the most efficient mode of operation of a free-running quantum cascade laser is indeed a pseudorandom frequency-modulated field with nearly constant intensity. We show that the optimum modulation period is commensurate with the gain recovery time of the laser medium and the optimum modulation amplitude is comparable to the gain bandwidth, behavior that has been observed in the experiments. |
| first_indexed | 2024-09-23T15:21:33Z |
| format | Article |
| id | mit-1721.1/115419 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T15:21:33Z |
| publishDate | 2018 |
| publisher | SPIE |
| record_format | dspace |
| spelling | mit-1721.1/1154192022-09-29T14:28:24Z Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers Henry, Nathan Khurgin, Jacob B. Burghoff, David Patrick Yang, Yang Hu, Qing Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Burghoff, David Patrick Yang, Yang Hu, Qing Recent research has shown that free-running quantum cascade lasers are capable of producing frequency combs in midinfrared and THz regions of the spectrum. Unlike familiar frequency combs originating from mode-locked lasers, these do not require any additional optical elements inside the cavity and have temporal characteristics that are dramatically different from the periodic pulse train of conventional combs. Frequency combs from quantum cascade lasers are characterized by the absence of sharp pulses and strong frequency modulation, periodic with the cavity round trip time but lacking any periodicity within that period. To explicate for this seemingly perplexing behavior, we develop a model of the gain medium using optical Bloch equations that account for hole burning in spectral, spatial, and temporal domains. With this model, we confirm that the most efficient mode of operation of a free-running quantum cascade laser is indeed a pseudorandom frequency-modulated field with nearly constant intensity. We show that the optimum modulation period is commensurate with the gain recovery time of the laser medium and the optimum modulation amplitude is comparable to the gain bandwidth, behavior that has been observed in the experiments. 2018-05-16T20:17:26Z 2018-05-16T20:17:26Z 2017-09 2013-06 2018-05-04T17:53:22Z Article http://purl.org/eprint/type/JournalArticle 0091-3286 http://hdl.handle.net/1721.1/115419 Henry, Nathan et al. “Pseudorandom Dynamics of Frequency Combs in Free-Running Quantum Cascade Lasers.” Optical Engineering 57, 1 (September 2017): 011009 © 2017 Society of Photo-Optical Instrumentation Engineers (SPIE) https://orcid.org/0000-0001-5848-2389 https://orcid.org/0000-0003-1982-4053 http://dx.doi.org/10.1117/1.OE.57.1.011009 Optical Engineering Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf SPIE SPIE |
| spellingShingle | Henry, Nathan Khurgin, Jacob B. Burghoff, David Patrick Yang, Yang Hu, Qing Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers |
| title | Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers |
| title_full | Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers |
| title_fullStr | Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers |
| title_full_unstemmed | Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers |
| title_short | Pseudorandom dynamics of frequency combs in free-running quantum cascade lasers |
| title_sort | pseudorandom dynamics of frequency combs in free running quantum cascade lasers |
| url | http://hdl.handle.net/1721.1/115419 https://orcid.org/0000-0001-5848-2389 https://orcid.org/0000-0003-1982-4053 |
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