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

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

Geiregat, P.A. (Universiteit Gent)
Houtepen, A.J. (TU Delft ChemE/Opto-electronic Materials; Universiteit Gent)
Van Thourhout, Dries (Universiteit Gent)
Hens, Zeger (Universiteit Gent)

2016-01-26

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.

All-optical signal processing
Intraband absorption
Nanocrystals
Transient absorption

http://resolver.tudelft.nl/uuid:f0408346-e7ce-4f1b-b23f-d986413e058d

https://doi.org/10.1021/acsnano.5b06630

2016-12-21

1936-0851

ACS Nano (online), 10 (1), 1265-1272

Accepted Author Manuscript

Institutional Repository

journal article

© 2016 P.A. Geiregat, A.J. Houtepen, Dries Van Thourhout, Zeger Hens