Micro-molded anamorphic reflector lens for image guided therapeutic/diagnostic catheters
A catheter system for optical coherence tomography includes an elongate catheter body, an optical fiber in the elongate catheter body, and an anamorphic lens assembly coupled with a distal end of the optical fiber. The optical fiber and the lens assembly are together configured to provide a common path for optical radiation reflected from a target and from a reference interface between the distal end of the optical fiber and the lens assembly.
1. A catheter for optical coherence tomography (OCT), comprising:
an elongate catheter body extending distally to proximally;
an optical fiber in the elongate catheter body; and
a lens assembly comprising a lens body having a concave proximal surface that is opposite from and at an angle relative to the distal end of the optical fiber, the lens body attached to and optically coupled with a distal end of the optical fiber by an interface medium;
wherein the proximal surface has a compound radius having a first radius along a first axis that is different from a second radius along a second axis;
wherein the proximal surface comprises a reflective material configured so that at least 90% of a light reaching the lens body from the distal end of the optical fiber reflects off of the proximal surface; and
wherein the optical fiber and the lens assembly are together configured to provide a common path for optical radiation reflected from a target and from a reference interface formed between the distal end of the optical fiber and the interface medium.
2. The catheter system of claim 1 , wherein the interface medium is an epoxy.
3. The catheter system of claim 1 , wherein a tangent of the proximal surface is at an angle of between about 40 degrees and 50 degrees relative to a longitudinal axis of the fiber.
4. The catheter system of claim 1 , wherein the reflective material comprises a reflective coating on the proximal surface.
5. The catheter system of claim 4 , wherein the reflective coating comprises gold.
6. The catheter system of claim 4 , wherein the reflective material comprises dielectric.
7. The catheter system of claim 4 , wherein the reflective coating has an optical density of greater than 3.0.
8. The catheter system of claim 1 , wherein the lens body comprises a polycarbonate material.
9. The catheter system of claim 1 , wherein a secondary reflection of optical radiation from an interface between the optical fiber and the lens assembly is less than −60 dB.
10. The catheter system of claim 1 , wherein the reference interface provides a reference reflection of between −28 and −42 dB.
11. The catheter system of claim 1 , wherein a radius of curvature of the proximal surface is between 0.2 mm and 1.5 mm.
12. The catheter system of claim 1 , further comprising a source of optical radiation configured to provide the light, wherein a reflective coating on the proximal surface has a thickness of at least ⅙ of an excitation wavelength of the source of optical radiation.
13. The catheter system of claim 1 , further comprising a source of optical radiation, receiving electronics configured to receive optical radiation reflected from the reference interface and the target, and a processor to generate an image of the target based upon the optical radiation received by the receiving electronics.