We propose a new laser irradiation method for the treatment of cutaneous lesions in plastic surgery. In general, lasers
with a spot size of 1 to 10 mm are used in irradiation on diseased skin. Although the target absorbs more light energy
according to the theory of selective photothermolysis, the surrounding tissue, however, is still somewhat damaged. In
proposed method, an f-theta lens, which is assembled by a shrink fitter, focuses the irradiation laser beam to a very fine
spot with the size of 125 μm. Guided by the captured object-image, such laser beam is conducted by a pair of
galvanometer-driven mirrors to irradiate only the desired tissue target without thermal damage to surrounding tissue.
Moreover, an optical coherence tomography, whose probe is capable of wide field of view, can be used to provide the
guidance information for the best treatment. The usefulness of the developed laser therapy apparatus was demonstrated
by performing an experiment on the removal of tattoo pigment.
A disturbance-free sinusoidal phase modulating laser diode interferometer using an accelerated integrating-buckets processing system is described. Several techniques make it suitable for use in on-machine measurements: the charge-coupled device (CCD)-based additive operation on integrating buckets shares the burden of data processing imposed on the computer to shorten the measurement time; the use of high-speed shutter function of the CCD camera enables each bucket to be collected without disturbance, while the interference signal's stability is enhanced with the feedback control during the entire data-collecting time; by using a dedicated waveform generator, the phase modulating system is more compact and the modulating signal matches the CCD camera's exposure time easily and exactly. A surface profile measurement on a diamond-turned aluminum disk is demonstrated to evaluate the performance of this system.
A disturbance-free sinusoidal phase modulating laser diode interferometer using integrating bucket method is described. Several techniques make it suitable for use in the in-process measurement: the charge-coupled device (CCD) based additive operation on integrating-buckets shares the burden of data processing imposed on the computer; the modulating signal is matched with the CCD camera’s exposure time easily and exactly by using a dedicated waveform generator; the use of high speed shutter function of the CCD camera enables each bucket collection to be insensitive to the noise, while the interference signal’s stability is enhanced with the feedback control during entire measurement time. A surface profile measurement on a diamond-turned aluminum disk was demonstrated to evaluate the performance of this system.
We propose a two-wavelength interferometer that is used to a stroboscopic step height measurement. Different from most two-wavelength interferometers, in present experiment, two slightly different wavelengths are simultaneously oscillated by currently and thermally controlling a laser diode to work at mode hop region. By use of this two-wavelength laser source, a Twyman-Green interferometer, whose reference arm and object arm have known step height r and unknown step height h, respectively, is constructed. Three independent interference patterns corresponding to different OPDs are formed and they can be simultaneously taken by a CCD camera. Furthermore, tilting the reference, spatial frequencies are introduced into the interference patterns. Taking the Fourier transform of these patterns, three fringe amplitudes are obtained and their expressions can be solved for the unknown step height. As we can capture clear image of the interference patterns in a very short time by use of the high speed shutter function of the CCD camera, the error induced by the external disturbance is farthest reduced.
We propose a sinusoidal phase modulating laser diode interferometer using an additive operating type of integrating bucket method. In previous integrating bucket method, four images, which are integrated values of the interference pattern detected by a CCD image sensor, are required. According to additive and subtractive operations in a calculator, the quadrature signals can be calculated from these images. While these operations are associated with the technical computing software, such as MATLAB, in a personal computer, it is quite fast, even if the images possess large size. In a standard-alone system with a CPU, however, this kind of operation expends unbearable time. To lighten the burden of the calculator, we tried to simplify the operation. That is, on the basis of integrating bucket method, the subtraction in the signal processing is transformed to the addition by use of the phase shifting technique. All additive operations are achieved with the CCD image sensor. In this interferometer, not only the calculating quantity is reduced, but also the number of required images is reduced. The surface profile of a diamond-turned aluminum disk was measured. The repeatability in the measurements was 5.93 nm rms.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.