Fast Modification of Microdischarge Emission Bands by Fracture of Sugar

Intensive light pulses with widths of about 10 ns were observed during the crack propagation by cleavage of crystalline sugar at atmospheric pressure. The observed light pulses were caused by a sequence of gas microdischarges (MDs). The pulses were detected in the UV/VIS and NIR wavelength ranges. First the light pulses appear in the UV/VIS wavelength range, and then after a delay of about 0.4–1.2 ns in the NIR wavelength range. This characteristic feature of MDs can be used for the characterization of crack propagation.