[1] Hariharan P,Steel W H,Wyant J C. Double grating interferometer with variable lateral shear[J]. Optics Communications,1974,11(3):317-320.

[2] Hanharan P,Hegedus Z S. Double grating interferometers Ⅱ. Application to collimated beams [J]. Optics Communications,1975,14(1):148-151.

[3] Lee Y J,Lambros J,Rosakis AJ . Analysis of coherent gradient sensing (CGS) by Fourier optics [J]. Optics and Lasers in Engineering,1996,25(1):25-53.

[4] Bruck H A,Rosakis A J. On the sensitivity of coherent gradient sensing: part Ⅰ-A theoretical investigation of accuracy in fracture mechanics applications[J].Optics and Lasers in Engineering,1992,17(2):83-101.

[5] Bruck H A,Rosakis A J. On the sensitivity of coherent gradient sensing: Part Ⅱ-An experimental investigation of accuracy in fracture mechanics applications[J]. Optics and Lasers in Engineering,1993,18(1):25-51.

[6] Tippur H V,Krishnaswamy S,Rosakis A J. Coherent gradient sensor for crack tip deformation measurements: analysis and experimental results[J]. International Journal of Fracture,1991,48(3): 193-204.

[7] Rosakis A J. Application of coherent gradient sensing (CGS) to the investigation of dynamic fracture problems [J]. Optics and Lasers in Engineering,1993,19(1-3):3-41.

[8] Mason J J,Lambros J,Rosakis A J. The use of a coherent gradient sensor in dynamic mixed-mode fracture mechanics experiments[J]. Journal of the Mechanics and Physics of Solids,1992,40 (3): 641-661.

[9] Liu C,Rosakis A J,Stout M G. Dynamic fracture toughness of a unidirectional graphite/epoxy composite[A]. ASME International Mechanical Engineering Congress and Exposition[C]. New York American Society of Mechanical Engineers,Applied Mechanics Division,2001.

[10] Hadek E,Medhat A,Tippur,Hareesh V. Dynamic fracture behavior of syntactic epoxy foams: Optical measurements using coherent gradient sensing[J]. Optics and Lasers in Engineering,2003,40(4):353-369.

[11] Park T S,Suresh S,Rosakis A J,et al. Measurement of full-field curvature and geometrical instability of thin film-substrate systems through CGS interferometry [J]. Journal of the Mechanics and Physics of Solids,2003,51(11-12) :2191-2211.

[12] Tippur H V,Sridhar K,Rosakis A J. Optical mapping of crack tip deformations using the methods of transmission and reflection coherent gradient sensing: a study of crack tip K-dominance [J]. International Journal of Fracture,1991,52(2):91-117.

[13] ASTM E 399,Standard test method for plane strain fracture toughness of metallic materials[S].