Patent ID: 7417741

Claim:
A scanning delay line for use in optical coherence tomography apparatus, comprising: an input port for admitting a collimated input beam; an output port for launching an output beam; a tiltable mirror; optical convergence means for converging light incident thereon; dispersive means for dispersing light incident thereon; and redirecting means for changing the direction of a beam incident thereon; and wherein said tiltable mirror, said optical convergence means, said dispersive means, and said redirecting means are arranged in an optical configuration such that in sequence: said dispersive means directs said input beam toward said optical convergence means; said optical convergence means directs said input beam received from said dispersive means toward said tiltable mirror; said tiltable mirror reflects said input beam received from said optical convergence means as a first return beam back toward said optical convergence means; said optical convergence means directs said first return beam received from said tiltable mirror toward said dispersive means; said dispersive means directs said first return beam received from said optical convergence means toward said redirecting means; and said redirecting means redirects said first return beam received from said dispersive means toward said tiltable mirror via said optical convergence means and bypassing said dispersive means and in a direction such that said tiltable mirror reflects said first return beam received from said dispersive means via said optical convergence means back toward said optical convergence means as a second return beam and said optical convergence means directs said second return beam received from said tiltable mirror toward said output port as part of an output beam bypassing said dispersive means and such that said output beam lies along substantially the same axis regardless of the angle of tilt of said tiltable mirror; and whereby tilting said mirror introduces a variable optical delay between said input and output ports.