ABSTRACT
Laser therapy has been demonstrated to be effective in treating many types of cutaneous vascular and pigmented lesions. Clinical and investigative studies on lasers are being published with increasing frequency, but is difficult to interpret and compare results because of lack of use of appropriate nomenclature regarding laser energy. We suggest that scientific communication in this expanding field will be improved if all future studies state: (1) irradiance (laser flux density) at the irradiated surface in watts/cm2, (2) laser beam cross-sectional area and shape at the irradiated surface, (3) laser pulse duration or exposure time in seconds, (4) pulse repetition rate (pulsed lasers) in pulses per second, (5) treatment time segments and intervals between treatment times, (6) total treated skin area in cm2, (7) total number of applied laser pulses or exposures, and (8) the type of laser used and its spectral distribution.
Subject(s)
Laser Therapy , Humans , Physical Phenomena , Physics , Skin Diseases/surgery , Terminology as TopicABSTRACT
A flashlamp pumped frequency-doubled Nd:YAG laser producing 7-nsec 2.8-mJ pulses at 530 nm and 400 pps has been developed for use in airborne bathymetry. A flashlamp gas mixture of krypton and xenon provides efficient laser operation and rapid lamp recovery. Pulse transmission mode operation is used to achieve a narrow pulse width. Thermally induced lensing and birefringence in the rod are compensated for in the optical resonator. Rapid, high repetition rate Pockels cell switching is accomplished with a thyratron driver. A CD*A crystal cut for 85 degrees phase matching at 55 degrees C is used to provide high conversion efficiency second harmonic generation.
ABSTRACT
Using suitable correcting optics, a 2x diffraction-limited beam has been obtained from a high power transverse flow dye laser. Beam divergence in the direction parallel to flow is controlled by a sound wave and may be compensated for externally.
ABSTRACT
An experimental investigation of a novel unstable laser resonator configuration is reported. The purpose of the novel configuration is to maximize the area that can be illuminated with uniform intense flux by a given laser device. This is accomplished by displacing the optical axis of the resonator to one edge of the optical cavity. The results indicate that the change causes no loss of device output power and has little effect on the beam quality. Additional experimental results are presented indicating the sensitivity of resonator performance to misalignment of the off-axis resonator.
ABSTRACT
To examine high energy CO(2) pulsed laser beams, reliable sampling and attenuation procedures were devised using the properties of coarse transmission gratings and diffuse scatter from specular metal mirrors. Details of measurements and alignment procedures are described including a single shot, nondisruptive method for effectively scanning the time integrated focal distribution of a high energy pulsed laser. In addition, it is shown that a simple multiple burn pattern technique can be used for the quantitative measurement of the integrated distribution. The data obtained demonstrate near diffraction-limited capability for large e-beam lasers with unstable resonators.
ABSTRACT
The optical quality of a pulsed atmospheric CO(2) electric laser is investigated. The density disturbances in the optical cavity are caused by edge waves originating at the anode and cathode. Volumetric heating effects associated with a nonuniform electric discharge are shown to be negligible. The disturbance propagating from the cathode results from a discontinuity in the spatial heating and the cathode fall. The wave emanating from the anode is associated with the presence of a solid surface that prevents the gas from expanding. As a result, lasers have to be designed with pulse durations much less than the acoustic transit time across the cavity.
