Photochemistry of refractive index structures in poly(methyl methacrylate) by femtosecond laser irradiation.
Femtosecond, subablation threshold photomodification of poly(methyl methacrylate) (PMMA) at 387 nm is explored to enable fabrication of optical components. Volatile fragment analysis (thermal desorption gas chromatography-mass spectrometry) and molecular weight distribution monitoring (size exclusion chromatography) suggest photochemical modification, involving direct cleavage of the polymer backbone and propagation via chain unzipping under formation of monomers, similar to the pyrolytic degradation of PMMA. Waveguides were produced in undoped, clinical-grade PMMA, showing an increased refractive index in the laser focal region (Dnmax=4x10(-3)).
Baum
Alexandra
A
Centre for Instrumentation and Analytical Science, The University of Manchester, UK.
Scully
Patricia J
PJ
Basanta
Maria
M
Thomas
C L Paul
CL
Fielden
Peter R
PR
Goddard
Nicholas J
NJ
Perrie
Walter
W
Chalker
Paul R
PR