Carrier-Envelope Phase Shift Using Linear Media

Abstract

The carrier-envelope phase in a train of optical pulses is varied utilizing the dispersive properties of lossless plates while the total dispersion in transmission is maintained practically constant. The plates include sloped surfaces and are mounted for displacement such that the ratio of the thicknesses of the two plates through which the optical pulses will pass can be varied by displacing the plates so as to shift the carrier-envelope phase in the optical pulses. In one embodiment, the plates include a barium fluoride wedge and a fumed silica wedge, wherein the wedges are bond together to form a composite structure with thicker and thinner portions of the wedges inversely matched.

1 . An optical system for controlling a carrier-envelope phase comprising:
 a light source configured to generate a train of optical pulses along an optical path;   a first plate positioned in the optical path, wherein the first plate has a thicker portion and a thinner portion with a range of thicknesses there between, and wherein the first plate has a refractive index, second order dispersion, and ratio of group and phase velocities for the optical pulses; and   a second plate positioned in the optical path, wherein the second plate has a thicker portion and a thinner portion with a range of thicknesses there between, wherein the thicker portion of the second plate is aligned with the thinner portion of the first plate, measured parallel to the optical path, and wherein the thinner portion of the second plate is aligned with the thicker portion of the first plate, measured parallel to the optical path, and wherein the second plate has a refractive index, second order dispersion, and ratio of group and phase velocities for the optical pulses,   wherein the refractive indices of the two plates and the second order dispersions of the optical pulses in the two plates both are substantially the same, and wherein the ratios of group and phase velocities for the optical pulses in the two plates are substantially different.   
     
     
         2 . The optical system of  claim 1 , further comprising a displacement mechanism coupled with the first and second plates to displace the plates in a plane orthogonal to the light path. 
     
     
         3 . The optical system of  claim 1 , wherein the plates are bond together. 
     
     
         4 . The optical system of  claim 1 , wherein the system is an interferometric autocorrelator with two arms, and wherein the plates are in one arm of the interferometric autocorrelator. 
     
     
         5 . The optical system of  claim 1 , wherein the combined thickness of the plates is between 1 and 2 mm. 
     
     
         6 . The optical system of  claim 1 , wherein the light source is a laser. 
     
     
         7 . The optical system of  claim 1 , wherein the light source is configured to generate a train of optical pulses with a pulse length of 2.5 to 7.5 femtoseconds along an optical path. 
     
     
         8 . The optical system of  claim 1 , wherein the second plate comprises silica glass. 
     
     
         9 . The optical system of  claim 8 , wherein the silica is fused silica. 
     
     
         10 . The optical system of  claim 8 , wherein the first plate comprises barium fluoride. 
     
     
         11 . The optical system of  claim 1 , wherein the first and second plates are both wedge shaped, though inversely oriented with respect to one another. 
     
     
         12 . A method for controlling carrier-envelope phase in an optical system that comprises:
 a light source configured to generate a train of optical pulses along an optical path;   a first plate positioned in the optical path, wherein the first plate has a thicker portion and a thinner portion with a range of thicknesses there between, and wherein the first plate has a refractive index, second order dispersion, and ratio of group and phase velocities for the optical pulses; and   a second plate positioned in the optical path, wherein the second plate has a thicker portion and a thinner portion with a range of thicknesses there between, wherein the thicker portion of the second plate is aligned with the thinner portion of the first plate, measured parallel to the optical path, and wherein the thinner portion of the second plate is aligned with the thicker portion of the first plate, measured parallel to the optical path, and wherein the second plate has a refractive index, second order dispersion, and ratio of group and phase velocities for the optical pulses,   wherein the refractive indices of the two plates and the second order dispersions of the optical pulses in the two plates both are substantially the same, and wherein the ratios of group and phase velocities for the optical pulses in the two plates are substantially different;   the method comprising transmitting a train of optical pulses along the optical path, the optical pulses including a lower-frequency envelope and a higher-frequency carrier within the envelope.