Influence of low temperature on white light emission from graphene-based microchip

Abstract

The laser-induced white emission of the graphene-based microchip was investigated under near-infrared region laser irradiation. The emission was characterized by an excitation threshold and an exponential dependence on the pump laser power. A decrease in temperature caused an increase in both the number of absorbed photons and the emission threshold. This dependence can be explained by the multiphoton ionization process in ( sp2, sp3) hybridized domains.

Closed Circle Measurements of Laser-Induced White Emission of Graphene Foam

“…A more detailed explanation of LIWE properties in graphene/graphite materials can be found in our earlier papers. 2,5,11,24 An increase in the excitation power of the laser beam caused an increase in the intensity of LIWE, and no saturation was detected. It should be noted that the CW excitation of graphene foam placed in a vacuum caused the heating of the sample, the temperature could reach up to 900 K. 5 Changing the temperature of the sample changes the properties of LIWE.…”

“…To check this hypothesis, the excitation time was reduced to t 0 ∼ 1 s, Δt = 20 s (Figure 5b). It should be noted that the rise and decay times for LIWE in graphene microchips are less than 10 ms, 24 indicating that 1 s of excitation is enough to reach the maximum intensity. Reducing the excitation time from 5 to 1 s (for each measurement point) caused the LIWE saturation to disappear.…”