Patent ID: 7643212

Claim:
A tunable optical rotational delay line apparatus for providing a continually adjustable time delay between two orthogonally polarized co-linear laser pulses, the rotational delay line apparatus comprising: a. a rotational delay crystal made of a parallel flat birefringent crystal having an ordinary refractiveindex n o and extra-ordinary refractive index n e , wherein the unique optic axis of said rotational delay crystal is oriented at an angle β to the rotational delay crystal surface normal, where β is greater than 0 degrees and less than 90 degrees; b. a means of rotating said rotational delay crystal about its surface normal; c. whereby a time delay between said two orthogonally polarized co-linear laser pulses that travel through said rotational delay crystal can be continually adjusted by i. inclining said surface normal of said rotational delay crystal at an angle θ to the direction of travel of said co-linear laser pulses, where θ=n o sin(β); ii. rotating said rotational delay crystal about its surface normal.