A benzopyrene compound represented by a general formula 1 below,where one of X1 and X2 represents a substituted or unsubstituted aryl group; another one of X1 and X2 represents a hydrogen atom; R represents an alkyl group; and n represents 0 or 1. In one embodiment, a method for producing methyl ester includes introducing a first charge into a reactor. One embodiment uses anisotropic diffractions in an AOTF to generate two near-collinear orthogonal linear polarization and slightly displaced beams that both pass via a test sample to deliver highly sensitive sample birefringence or material optical retardation measurements.