Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers
In research and engineering, short laser pulses are fundamental for metrology and communication. The generation of pulses by passive mode-locking is especially desirable due to the compact setup dimensions, without the need for active modulation requiring dedicated external circuitry. However, well-...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
De Gruyter
2024-02-01
|
| Series: | Nanophotonics |
| Subjects: | |
| Online Access: | https://doi.org/10.1515/nanoph-2023-0657 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850159197387227136 |
|---|---|
| author | Seitner Lukas Popp Johannes Haider Michael Dhillon Sukhdeep S. Vitiello Miriam S. Jirauschek Christian |
| author_facet | Seitner Lukas Popp Johannes Haider Michael Dhillon Sukhdeep S. Vitiello Miriam S. Jirauschek Christian |
| author_sort | Seitner Lukas |
| collection | DOAJ |
| description | In research and engineering, short laser pulses are fundamental for metrology and communication. The generation of pulses by passive mode-locking is especially desirable due to the compact setup dimensions, without the need for active modulation requiring dedicated external circuitry. However, well-established models do not cover regular self-pulsing in gain media that recover faster than the cavity round trip time. For quantum cascade lasers (QCLs), this marked a significant limitation in their operation, as they exhibit picosecond gain dynamics associated with intersubband transitions. We present a model that gives detailed insights into the pulse dynamics of the first passively mode-locked QCL that was recently demonstrated. The presence of an incoherent saturable absorber, exemplarily realized by multilayer graphene distributed along the cavity, drives the laser into a pulsed state by exhibiting a similarly fast recovery time as the gain medium. This previously unstudied state of laser operation reveals a remarkable response of the gain medium on unevenly distributed intracavity intensity. We show that in presence of strong spatial hole burning in the laser gain medium, the pulse stabilizes itself by suppressing counter-propagating light and getting shortened again at the cavity facets. Finally, we study the robustness of passive mode-locking with respect to the saturable absorber properties and identify strategies for generating even shorter pulses. The obtained results may also have implications for other nanostructured mode-locked laser sources, for example, based on quantum dots. |
| format | Article |
| id | doaj-art-df436e96cded49a9908a85da7c9f2987 |
| institution | OA Journals |
| issn | 2192-8614 |
| language | English |
| publishDate | 2024-02-01 |
| publisher | De Gruyter |
| record_format | Article |
| series | Nanophotonics |
| spelling | doaj-art-df436e96cded49a9908a85da7c9f29872025-08-20T02:23:36ZengDe GruyterNanophotonics2192-86142024-02-0113101823183410.1515/nanoph-2023-0657Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbersSeitner Lukas0Popp Johannes1Haider Michael2Dhillon Sukhdeep S.3Vitiello Miriam S.4Jirauschek Christian5TUM School of Computation, Information and Technology, Technical University of Munich (TUM), D-85748Garching, GermanyTUM School of Computation, Information and Technology, Technical University of Munich (TUM), D-85748Garching, GermanyTUM School of Computation, Information and Technology, Technical University of Munich (TUM), D-85748Garching, GermanyLaboratoire de Physique de l’Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, FranceNEST, CNR – Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, ItalyTUM School of Computation, Information and Technology, Technical University of Munich (TUM), D-85748Garching, GermanyIn research and engineering, short laser pulses are fundamental for metrology and communication. The generation of pulses by passive mode-locking is especially desirable due to the compact setup dimensions, without the need for active modulation requiring dedicated external circuitry. However, well-established models do not cover regular self-pulsing in gain media that recover faster than the cavity round trip time. For quantum cascade lasers (QCLs), this marked a significant limitation in their operation, as they exhibit picosecond gain dynamics associated with intersubband transitions. We present a model that gives detailed insights into the pulse dynamics of the first passively mode-locked QCL that was recently demonstrated. The presence of an incoherent saturable absorber, exemplarily realized by multilayer graphene distributed along the cavity, drives the laser into a pulsed state by exhibiting a similarly fast recovery time as the gain medium. This previously unstudied state of laser operation reveals a remarkable response of the gain medium on unevenly distributed intracavity intensity. We show that in presence of strong spatial hole burning in the laser gain medium, the pulse stabilizes itself by suppressing counter-propagating light and getting shortened again at the cavity facets. Finally, we study the robustness of passive mode-locking with respect to the saturable absorber properties and identify strategies for generating even shorter pulses. The obtained results may also have implications for other nanostructured mode-locked laser sources, for example, based on quantum dots.https://doi.org/10.1515/nanoph-2023-0657terahertzquantum cascade lasergraphenefrequency combpassive mode-lockingmaxwell–bloch |
| spellingShingle | Seitner Lukas Popp Johannes Haider Michael Dhillon Sukhdeep S. Vitiello Miriam S. Jirauschek Christian Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers Nanophotonics terahertz quantum cascade laser graphene frequency comb passive mode-locking maxwell–bloch |
| title | Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers |
| title_full | Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers |
| title_fullStr | Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers |
| title_full_unstemmed | Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers |
| title_short | Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers |
| title_sort | theoretical model of passive mode locking in terahertz quantum cascade lasers with distributed saturable absorbers |
| topic | terahertz quantum cascade laser graphene frequency comb passive mode-locking maxwell–bloch |
| url | https://doi.org/10.1515/nanoph-2023-0657 |
| work_keys_str_mv | AT seitnerlukas theoreticalmodelofpassivemodelockinginterahertzquantumcascadelaserswithdistributedsaturableabsorbers AT poppjohannes theoreticalmodelofpassivemodelockinginterahertzquantumcascadelaserswithdistributedsaturableabsorbers AT haidermichael theoreticalmodelofpassivemodelockinginterahertzquantumcascadelaserswithdistributedsaturableabsorbers AT dhillonsukhdeeps theoreticalmodelofpassivemodelockinginterahertzquantumcascadelaserswithdistributedsaturableabsorbers AT vitiellomiriams theoreticalmodelofpassivemodelockinginterahertzquantumcascadelaserswithdistributedsaturableabsorbers AT jirauschekchristian theoreticalmodelofpassivemodelockinginterahertzquantumcascadelaserswithdistributedsaturableabsorbers |