Title :
CW radio-frequency excited white-light He-Cd+ laser
Author :
Reich, Norbert ; Mentel, Jürgen ; Mizeraczyk, Jerzy
Author_Institution :
Allgemeine Elektrotechnik und Elektrooptik, Ruhr-Univ., Bochum, Germany
fDate :
11/1/1995 12:00:00 AM
Abstract :
We report on the design and performance of a continuous-wave transverse capacitively coupled radio-frequency excited He-Cd+ laser, which is capable of simultaneously delivering stable, tens-milliwatt power output at the three primary spectral lines blue: (λ=441.6 nm), green (λ=533.7 nm and λ=537.8 nm), and red (λ=635.5 nm and λ=636.0 nm). Mixing these lines can result in the laser beam featured by a wide band of colors, including white color. The radio-frequency discharge, that excited the He-Cd mixture inside an alumina ceramic tube (400 mm length and 4 mm inner diameter) inserted into the fused silica tubing, operated between 400 mm long and 4 mm wide outer electrodes. Transformation of the radio-frequency discharge impedance to the 50-Ω output resistance of the radiofrequency generator and symmetrization of the radio-frequency voltage were performed by a special matching circuit. Under single-line operation the He-Cd+ laser output powers of 60 mW, 38 mW and 14 mW were obtained for the blue, green and red lines, respectively, at an input radio-frequency power of 400 W. Owing to the power interaction between the laser oscillations at red and green higher laser output powers in red and green are possible under multi-line operation. At optimum conditions the white-light laser output power of about 60 mW is obtainable from the laser tube of 40 cm active length. The rms noise-to-signal ratio (lower than 0.4%) of the laser output power of the radio-frequency excited He-Cd+ laser was comparable to that of hollow cathode He-Cd+ lasers and much lower than that of conventional positive column He-Cd+ lasers. The presented laser has exhibited stable operation for more than 400 hours, showing ability to become a long life laser
Keywords :
cadmium; capacitance; excited states; helium; high-frequency discharges; ion lasers; laser beams; life testing; optical testing; optimisation; 40 cm; 400 W; 400 h; 441.6 nm; 50 ohm; 533.7 nm; 60 mW; 635.5 nm; 636.0 nm; CW radio-frequency excited white-light He-Cd+ laser; He-Cd; active length; alumina ceramic tube; continuous-wave transverse capacitively coupled radio-frequency excited He-Cd+ laser; fused silica tubing; hollow cathode He-Cd+ lasers; long life laser; multi-line operation; optimum conditions; outer electrodes; output powers; radio-frequency discharge; radio-frequency voltage; radiofrequency generator; rms noise-to-signal ratio; single-line operation; special matching circuit; spectral lines; stable operation; symmetrization; white color; white-light laser output power; Laser beams; Laser excitation; Laser noise; Laser stability; Optical coupling; Optical design; Power generation; Power lasers; Radio frequency; Wideband;
Journal_Title :
Quantum Electronics, IEEE Journal of