Laser beam retention in the vibratory dipoles of silica glass surfaces.

We report experimental results for the suppression of a weak TEM_oo probe cw-laser beam due to a brighter coupling laser. Our studies include a low coherent regime, when two TEMoo cw-laser beams of 650nm (weak probe) and 532nm (brighter coupler) are irradiating the same crown glass surface. At about 59 degrees measured from the normal of the dielectric surface, our experimental reflectance of the probe laser beam shows a deep minimum that can be interpreted as being the signature of the suppression of a probe laser beam due to a brighter coupling laser. In our case, the interaction between the lasers is assisted by an isotropic energy background from a capacitor voltage set across the dielectric. For voltages lower than 0.3 volts, a weak interference pattern with evenly spaced fringes on the right wing of the signal is observed. For voltages larger than 3 volts, the coherent interference of the two lasers is diminished because of a larger energy background. Further, we looked to a highly coherent regime, with two TEMoo diode cw-lasers of 532 nm irradiating the same 2mm spot on a crown glass surface. A nicely resolved interference pattern is now shown in the parallel component of the reflectance at five capacitor voltages: 0, 0.3, 0.6, 3.0 and 6.0 volts. At voltages lower than 0.3 volts, we observe a clear and regular interference pattern with 0.6 degrees between adjacent maxima and minima. For voltages greater than 0.6 volts, the interference pattern changes as the voltage increases into an uneven distribution of maxima-minima, as well as a strong attenuation of the amplitudes is observed. This fact is interpreted as being due to a larger energy background that diminishes the coherence between the lasers.