tailieunhanh - Advances in Lasers and Electro Optics Part 13

Tham khảo tài liệu 'advances in lasers and electro optics part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | The Physics of Ghost Imaging 583 Fig. 20. Schematic illustration of 2 Ị Ej I E 2 El I Eịi 2. It is clear that the amplitude pairs jl X 12 with 11 X j2 where j and 1 represent all point sub-sources pair by pair will experience equal optical path propagation and superpose constructively when Di and D2 are located at Pl p2 Zi z2. This interference is similar to symmetrizing the wavefunction of identical particles in quantum mechanics. It is not difficult to see the nonlocal nature of the superposition shown in Eq. 59 . In Eq. 59 G 2 rn t1 r2 t2 is written as a superposition between the paired sub-fields Ej r1 ti Efrb t2 and E1 r1 t1 Ej r2 t2 . The first term in the superposition corresponds to the situation in which the field at Di was generated by the jth sub-source and the field at D2 was generated by the 1th sub-source. The second term in the superposition corresponds to a different yet indistinguishable situation in which the field at D1 was generated by the lth sub-source and the field at D2 was generated by the jth sub-source. Therefore an interference is concealed in the joint measurement of D1 and D2 which physically occurs at two space-time points r1 t1 and r2 t2 . The interference corresponds to EjiEi2 E1iEj2 2. It is easy to see from Fig. 20 the amplitude pairs jl X 12 with 11 X j2 j 1 X 1 2 with 1 1 X j 2 jl X 1 2 with 1 1 X j2 and j l X 12 with 11 X j 2 etc. pair by pair experience equal total optical path propagation which involves two arms of D1 and D2 and thus superpose constructively when D1 and D2 are placed in the neighborhood of Pl p j Z1 z2. Consequently the summation of these individual constructive interference terms will yield a maximum value. When Pl p2 zl z2 however each pair of the amplitudes may achieve different relative phase and contribute a different value to the summation resulting in an averaged constant value. It does not seem to make sense to claim a nonlocal interference between Ej goes to D1 X El goes to D2 and E1 goes to D1 X Ej