Continuous-wave Beam Research Articles

色素レーザーによる血管腫の治療

So far there has been many kinds of treatmant for hemangioma, bat none of them are satisfactory.In this experiments, the author used newly devised Dye Laser which be to intermittent pulse beams and could produce beams of different kinds of wave length.The author compared the Laser absorption of the hemangioma with that of the haemoglobin of the red blood cell and found both corelated considerably.From upper comparison, the author chose beams of 610 nm and 575nm nave length and applied them to the hemangiomatous lesion and compared their effects to the tissue. It became clear that the beam of 577nm wave length was absorped far more selectively to the Itemangiomatous tissue than that of 610nm and the tissue damages were found mostly in the hemangiomatous area, lieving the surrounding normal tissue mostly unchanged.As to the selective treatment of the lesion, there are the important factors, one is wave length and the other is the heat transmitting through the tissue.From these points of view, Dye Laser seems to be more prosperous as to the selective effect than other continuous wave beams.

Theory of continuous-wave beam propagation in nonlinear optical waveguides

The paraxial approximation is applied to calculate the propagation characteristics of cw beams possessing Gaussian spatial profiles in nonlinear optical waveguides. For powers below the critical power for self-focusing in a homogeneous medium, we find that the waveguide effect dominates, i.e., the beam becomes trapped and the spot size varies sinusoidally. Above the critical power, the propagation is dominated by nonlinearity; the beam becomes unstable and displays self-focusing analogous to that in a homogeneous medium. Mode mixing is defined in terms of the nonlinearity-induced mixing of the initially excited modes at the guide face, and explicit expressions are obtained for the mode mixing for special cases. This mixing vanishes only if the spot size is a constant, a condition that can be satisfied only for special values of the parameters in longitudinally homogeneous, lossless guides.

The NASA High-Power Carbon Dioxide Laser A Versatile Tool for Laser Applications

The NASA Lewis Research Center has designed and fabricated a closed-cycle, continuous wave (CW), carbon dioxide (CO2) high-power laser to support research for the identification and evaluation of possible high-power laser applications. The device is designed to generate up to 70 kW of laser power in annular-shape beams from 1 to 9 cm in diameter. Electric discharge, either self-sustained or electron-beam-sustained, is used for excitation. This laser facility can be used in two ways. First, it provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high-power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams, all of which are important whether the laser application is government or industry oriented. Second, the facility provides a well-defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

New method for cascade-free lifetime measurements

A new method is presented for cascade-free high-precision lifetime measurements of highly excited atomic states. Experimental examples are given for the lifetimes of the ${\mathrm{Ba}}^{+}$ $6p ^{2}P_{\frac{3}{2}}$ level and the Ne $3p ^{\ensuremath{'}}[\frac{3}{2}]_{2}$ level. The experimental arrangement uses a fast ion beam which is excited in a gas cell and, after a definite time of flight, is further excited by a continuous-wave intracavity dye-laser beam. Further possible applications of the method are mentioned.

Infrared Techniques for Surveillance and Crime Deterrence

There are millions of dollars worth of optical surveillance equipment in use, nearly all of it useless after dark. To provide greater security in the dusk to dawn period, a number of infrared surveillance devices have been developed. A variety of techniques are now being employed, including pulsed and continuous-wave beams in both the direct and backscatter detection modes. The unique advantages of infrared technology relative to ultrasonics and microwaves will determine future trends in the area of surveillance and crime deterrence.

Basic Design Considerations--Automatic Navigator AN/APN-67

Some of the considerations involved in the design of the Automatic Navigator, AN/APN-67, are presented along with a description and photographs of the equipment design selected. Characteristics of the Doppler signal are also described. The microwave part of the system utilizes two continuous-wave pencil beams generated by a klystron transmitter and a single fixed mounted, space duplexed antenna with offset antenna feeds. The Doppler data are stabilized by use of computing elements and vertical reference data. Advantages of this design relative to other alternatives are pointed out.