We show that a Ⅲ-V semiconductor vertical external-cavity surface-emitting laser(VECSEL) can be engineered to generate light with a customizable spatiotemporal structure. Temporal control is achieved through the emis...We show that a Ⅲ-V semiconductor vertical external-cavity surface-emitting laser(VECSEL) can be engineered to generate light with a customizable spatiotemporal structure. Temporal control is achieved through the emission of temporal localized structures(TLSs), a particular mode-locking regime that allows individual addressing of the pulses traveling back and forth in the cavity. The spatial profile control relies on a degenerate external cavity, and it is implemented due to an absorptive mask deposited onto the gain mirror that limits the positive net gain within two circular spots in the transverse section of the VECSEL. We show that each spot emits spatially uncorrelated TLSs. Hence, the spatiotemporal structure of the light emitted can be shaped by individually addressing the pulses emitted by each spot. Because the maximum number of pulses circulating in the cavity and the number of positive net-gain spots in the VECSEL can be increased straightforwardly, this result is a proof of concept of a laser platform capable of handling light states of scalable complexity. We discuss applications to three-dimensional alloptical buffers and to multiplexing of frequency combs that share the same laser cavity.展开更多
Optically driven photoconductive switches are one of the predominant sources currently used in terahertz im-aging systems.However,owing to their low average powers,only raster-based images can be taken,resulting in sl...Optically driven photoconductive switches are one of the predominant sources currently used in terahertz im-aging systems.However,owing to their low average powers,only raster-based images can be taken,resulting in slow acquisition.In this work,we show that by placing a photoconductive switch within a cavity,we are able to generate absolute average THz powers of 181μW with the frequency of the THz emission centered at 1.5 THz-specifications ideally adapted to applications such as non-destructive imaging.The cavity is based on a metal-insulator-metal structure that permits an en hancement of the average power by almost 1 order of magnitude compared to a standard structure,while conserving a broadband spectral response.We demonstrate proof-of-principle real-time imaging using this source,with the broadband spectrum permitting to eliminate strong diffraction artifacts.展开更多
The optical properties of germanium can be tailored by combining strain engineering and n-type doping.In this paper,we review the recent progress that has been reported in the study of germanium light emitters for sil...The optical properties of germanium can be tailored by combining strain engineering and n-type doping.In this paper,we review the recent progress that has been reported in the study of germanium light emitters for silicon photonics.We discuss the different approaches that were implemented for strain engineering and the issues associated with n-type doping.We show that compact germanium emitters can be obtained by processing germanium into tensile-strained microdisks.展开更多
基金Région PACA (OPTIMAL)Agence Nationale de la Recherche (ANR-18-CE24-0002)。
文摘We show that a Ⅲ-V semiconductor vertical external-cavity surface-emitting laser(VECSEL) can be engineered to generate light with a customizable spatiotemporal structure. Temporal control is achieved through the emission of temporal localized structures(TLSs), a particular mode-locking regime that allows individual addressing of the pulses traveling back and forth in the cavity. The spatial profile control relies on a degenerate external cavity, and it is implemented due to an absorptive mask deposited onto the gain mirror that limits the positive net gain within two circular spots in the transverse section of the VECSEL. We show that each spot emits spatially uncorrelated TLSs. Hence, the spatiotemporal structure of the light emitted can be shaped by individually addressing the pulses emitted by each spot. Because the maximum number of pulses circulating in the cavity and the number of positive net-gain spots in the VECSEL can be increased straightforwardly, this result is a proof of concept of a laser platform capable of handling light states of scalable complexity. We discuss applications to three-dimensional alloptical buffers and to multiplexing of frequency combs that share the same laser cavity.
基金H2020 Future and Emerging Technologies(MIRBOSE 737017)French RENATECH network.
文摘Optically driven photoconductive switches are one of the predominant sources currently used in terahertz im-aging systems.However,owing to their low average powers,only raster-based images can be taken,resulting in slow acquisition.In this work,we show that by placing a photoconductive switch within a cavity,we are able to generate absolute average THz powers of 181μW with the frequency of the THz emission centered at 1.5 THz-specifications ideally adapted to applications such as non-destructive imaging.The cavity is based on a metal-insulator-metal structure that permits an en hancement of the average power by almost 1 order of magnitude compared to a standard structure,while conserving a broadband spectral response.We demonstrate proof-of-principle real-time imaging using this source,with the broadband spectrum permitting to eliminate strong diffraction artifacts.
基金“Triangle de la Physique”under the Gerlas convention and by Agence Nationale de la Recherche under the GRAAL convention(ANR Blanc call 2011 BS0300401)。
文摘The optical properties of germanium can be tailored by combining strain engineering and n-type doping.In this paper,we review the recent progress that has been reported in the study of germanium light emitters for silicon photonics.We discuss the different approaches that were implemented for strain engineering and the issues associated with n-type doping.We show that compact germanium emitters can be obtained by processing germanium into tensile-strained microdisks.
