Time-Resolved Picosecond Optical Study of Laser-Excited Graphite

1985 ◽  
Vol 51 ◽  
Author(s):  
C. Y. Huang ◽  
A. M. Malvezzi ◽  
J. N. Liu ◽  
N. Bloembergen
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Temperature Gradient ◽  
Threshold Fluence ◽  
Optical Study ◽  
Time Resolved ◽  
High Temperature Gradient ◽  
Probe Technique ◽  
Pump And Probe ◽  
New Phase

ABSTRACTThe pump-and-probe technique is employed to perform picosecond timeresolved measurements of the reflectivity changes in highly oriented pyrolitic graphite excited by 0.532-μm pump pulses. At low pump fluences, the presence of a short-lived plasma and a high-temperature gradient gives rise to an increase in the reflectivity probed at 1.9 μm but causes a decrease at 1.064 μm. At the threshold fluence, 140 mJ/cm2, the reflectivity drops abruptly, marking a phase transformation. Above the threshold, the reflectivity drops to -0.2 from its original value of 0.42 at 1.064 μm and to -0.4 from its ambient value of 0.50 at 1.9 μm. This new phase persists only for a few nanoseconds.

scholarly journals Time-Resolved Picosecond Reflectivity Study of Laser-Excited Layered Compounds

1986 ◽  
Vol 74 ◽  
Author(s):  
C. Y. Huang ◽  
A. M. Malvezzi ◽  
N. Bloembergen ◽  
F.J. Di Salvo
Keyword(s):  
Phase Transformation ◽  
Laser Pulses ◽  
High Temperature Phase ◽  
Layered Compounds ◽  
Temperature Phase ◽  
Threshold Fluence ◽  
Time Resolved ◽  
High Fluences ◽  
A Value ◽  
Pump And Probe

AbstractWe have employed the pump-and-probe technique to perform picosecond time resolved measurements of the reflectivity changes in two archetypal layered compounds, IT-TiS2 and lT-TiSe2 probed at 1.064 μm after pumping by 20 ps, .532 μm laser pulses. At the threshold fluence, ∼ 40 mJ/cm2, the reflectivity drops sharply, marking the occurrence of a phase transformation on the surface of the sample. Above threshold, the reflectivity reaches a value as low as ∼0.1 at high fluences, strongly suggesting that, like in graphite, the high temperature phase is not metallic.

New Phase Transformation in InSb at High Pressure and High Temperature

1967 ◽  
Vol 38 (5) ◽  
pp. 2042-2046 ◽  
Author(s):  
M. D. Banus ◽  
Mary C. Lavine
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
High Temperature ◽  
New Phase
Sign in / Sign up

Export Citation Format

Share Document