Thermooptical excitation of sound by Bessel light beams in crystalline media with internal stress

Photoacoustic transformation of Bessel light beams in magnetoactive superlattices

“…Thermal energy is released in the sample due to the modulated absorption at modulation frequency Ω; the temperature field distribution T(z, t) in the superlattice can be determined by solving the equation [11,12] …”

“…The joint solution to heat conduction equation (12) and the equations for thermoelastic strains in the sample under study and piezoelectric transducer with a thickness l 1 ,…”

“…One efficient method is based on the laser excitation of sound in the media under study [10,11]. As was shown in [12][13][14][15], the use of different polarization modes of Bessel light beams (BLBs) as sound-exciting radiation [16] is promising for this method, because these beams have a number of unique properties (for example, they are not diffracted when they propagate in space [17][18][19]). An important specific feature of BLBs is the occurrence of a radial energy flux, which compensates for the change in the light-beam transversality when screened the beam central region [20].…”