English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The electromagnetic response of Dirac semimetals in the infrared andterahertz frequency ranges is attracting growing interest for potentialapplications in optoelectronics and nonlinear optics. The interplay between thefree-carrier response and interband transitions in the gapless, lineardispersion relation plays a key role in enabling novel functionalities. Here weinvestigate ultrafast dynamics in thin films of a photoexcited Dirac semimetalCd$_3$As$_2$ by probing the broadband response functions as complex quantitiesin the multiterahertz region (10-45 THz, 40-180 meV, or 7-30 $\mu$m), whichcovers the crossover between the inter and intraband response. We resolvedynamics of the photoexcited nonthermal electrons which merge with originallyexisting carriers to form a single thermalized electron gas and how it isfacilitated by high-density excitation. We also demonstrate that a largereduction of the refractive index by 80% dominates the nonequilibrium infraredresponse, which can be utilized for designing ultrafast switches in activeoptoelectronics.

Tracking ultrafast change of multiterahertz broadband response functions in a photoexcited Dirac semimetal Cd$_3$As$_2$ thin film