Two major authors write about the metaphor of diffraction, Karen Barad and Donna Haraway. They explain how diffraction is a method for reading and writing based upon the physical phenomena. Diffraction is a way of coping with epistemological problems of representation (invisible knowledge maker as a false sense of objectivity, self-vision of reflexivity as totalizing and undermining knowledge claims).
To paraphrase Haraway, from "Modest_Witness@Second_Millenium.FemaleMan_Meets_OncoMouse" diffraction is an attempt to make differences while recording interactions, interference, and reinforcement. It does not have an origin and has a heterogeneous history. In addition, the practice of diffractive reading and writing never sediments the relationship between signifier and signified. Van der Tuin explains, "Diffraction is meant to disrupt linear and fixed causalities, and to work toward ‘‘more promising interference patterns’’ (26). She also explains that this can be practiced by reading texts through one another, and rewriting.This disrupts the temporality of a piece of writing, transverses boundaries such as discipline, and can change meanings in different contexts opening up meaning.
Further Reading

Barad, Karen Michelle. //Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning//. Durham: Duke UP, 2007. Print.

Haraway, Donna. //Modest_Witness@Second_Millenium: FemaleMan_Meets_OncoMouse : Feminism and Tehnoscience//. New York: Routledge, 1997.

Schneider, J. "Reflexive/Diffractive Ethnography." //Cultural Studies Critical Methodologies//2.4 (2002): 460-82.

van der Tuin, Iris. "A Different Starting Point, a Different Metaphysics’’: Reading Bergson and Barad Diffractively." //Hypatia// 26.1 (2011): 22-42. Web. 7 Dec. 2011