Gaussian focal plane

A Gaussian beam is focused and made to pass through the nonlinear medium. The output power is measured as a function of the sample position in the z-direction (with respect to the focal plane). The analysis of the transmitted intensity power profile provides the sign and magnitude of x ... 

Fig. 1.39 Experimental arrangement for resonant two-photon two-color ionization with two cw lasers. The insert shows the optimum overlap of the Gaussian intensity profiles in the focal plane...

A nearly parallel Gaussian beam is expanded by a telescope with two lenses of focal lengths / = 1 cm and fi = 10 cm. The spot size at the entrance lens is If = 1 mm. An aperture in the common focal plane of the two lenses acts as a spatial filter to improve the quality of the wavefront in the expanded beam (why ). What is the diameter of this aperture, if 95% of the intensity is transmitted ... 

In the focal plane of a Gaussian laser beam with 71 = 200mW focused down to a beam waist of w = lOjxm (Iq = 1.2 x 10 W/m ), the radial intensity gradient is dl/dr = which gives for... 

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