We outline an all-optical and noncontact approach for controlled laser heating and measurement of the resultant temperature distribution at the surface of a material, respectively. We show how the boundary conditions of the heating problem may be controlled optically through shaping of the pump light and use the examples of both Gaussian and flat-top beams. These two beams, together with appropriate nonoptical boundary control, allow for the laser-induced thermal study of materials with and without thermal stress. We illustrate the technique on an industrial diamond sample where a gradient and uniform temperature profile on the surface of the diamond was successfully created and measured. We use the technique to study the thermally induced degradation of industrial diamond in a controlled manner.
This paper presents an implementation of a laser beam shaping system for both heating a diamond tool and measuring
the resulting temperature optically. The influence the initial laser parameters have on the resultant temperature profiles is
shown experimentally and theoretically. A CO<sub>2</sub> laser beam was used as the source to raise the temperature of the
diamond tool and the resultant temperature was measured by using the blackbody principle. We have successfully
transformed a Gaussian beam profile into a flat-top beam profile by using a diffractive optical element as a phase
element in conjunction with a Fourier transforming lens. In this paper, we have successfully demonstrated temperature
profiles across the diamond tool surface using two laser beam profiles and two optical setups, thus allowing a study of
temperature influences with and without thermal stress. The generation of such temperature profiles on the diamond tool
in the laboratory is important in the study of changes that occur in diamond tools, particularly the reduced efficiency of
such tools in applications where extreme heating due to friction is expected.