All-optical wavelength conversion by picosecond burst absorption in colloidal PbS quantum dots

Pieter Geiregat*, Arjan J. Houtepen, Dries Van Thourhout, Zeger Hens

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
39 Downloads (Pure)


All-optical approaches to change the wavelength of a data signal are considered more energy-and cost-effective than current wavelength conversion schemes that rely on back and forth switching between the electrical and optical domains. However, the lack of cost-effective materials with sufficiently adequate optoelectronic properties hampers the development of this so-called all-optical wavelength conversion. Here, we show that the interplay between intraband and band gap absorption in colloidal quantum dots leads to a very strong and ultrafast modulation of the light absorption after photoexcitation in which slow components linked to exciton recombination are eliminated. This approach enables all-optical wavelength conversion at rates matching state-of-the-art convertors in speed, yet with cost-effective solution-processable materials. Moreover, the stronger light-matter interaction allows for implementation in small-footprint devices with low switching energies. Being a generic property, the demonstrated effect opens a pathway toward low-power integrated photonics based on colloidal quantum dots as the enabling material.

Original languageEnglish
Pages (from-to)1265-1272
Number of pages8
JournalACS Nano
Issue number1
Publication statusPublished - 26 Jan 2016

Bibliographical note

Accepted Author Manuscript


  • All-optical signal processing
  • Intraband absorption
  • Nanocrystals
  • Transient absorption


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