Dipole aligned NLO chromophores

A nonlinear optical material, comprising a recrystallized crystalline bridged di-arene having a net macroscopic dipole moment and described by the formula:

• D—Ar1—E1═N—N═E2—Ar2—A
• wherein:
• Ar1 and Ar2 are arenyl groups which may be the same or different and which are selected from the group consisting of mononuclear aryl groups, and conjugated di-nuclear aryl groups;
• D is an electron donor substituent on the first aryl group;
• A is an electron acceptor substituent on the second aryl group;
• E1 and E2 are each independently substituted or unsubstituted methylene or ethylene groups which may be the same or different and which have substituent side groups which contain 1 or 2 carbon atoms and are in a racemic relationship,
• said material having a macroscopic dipole alignment factor of at least 0.1.

In a process for electro-optical modification of a beam of monochromatic electromagnetic radiation, the steps comprising:

• a. providing a light-modifying cell containing a nonlinear optical material comprising a crystalline azine bridged di-arene having a macroscopic dipole alignment factor of at least 0.1 and described by the formula D—Ar1—B—Ar2—A;
• wherein:
• Ar1 is a first arenyl group and Ar2 is a second arenyl group which may be the same as or different from Ar1;
• D is an electron donor substituent on said first arenyl group;
• A is an electron acceptor group on said second arenyl group;
• and
• B is an azine bridge interconnecting said first and second arenyl groups;
• said material having a macroscopic dipole alignment factor of at least 0.1;
• b. applying a primary beam of monochromatic electromagnetic radiation to said modulating cell;
• c. producing a secondary beam of monochromatic radiation from said cell having a modified electromagnetic characteristic in relation to the corresponding electromagnetic characteristic of the applied radiation beam;
• and
• d. applying said secondary beam to a utilization system.