All-Optical Wavelength Conversion by Picosecond Burst Absorption in Colloidal PbS Quantum Dots

作者：Geiregat Pieter^*; Houtepen Arjan J; Van Thourhout Dries; Hens Zeger^*

来源：ACS Nano, 2016, 10(1): 1265-1272.

DOI：10.1021/acsnano.5b06630

• all-optical signal processing
• nanocrystals
• intraband absorption
• transient absorption

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 tow-power integrated photonics based on colloidal quantum dots as the enabling material.

• 出版日期2016-1