Optical coherence tomography for biological imaging

A catheter for use with optical coherence tomography, comprising:

• an elongate catheter body;
• an optical fiber in the elongate catheter body configured to connect to a source of optical radiation and receiving electronics, the optical fiber having a core providing a common path for optical radiation reflected from a reference interface and a target and to transmit the optical radiation to receiving electronics, the core having a first refractive index;
• and
• an interface medium at the reference interface and in physical and optical contact with the optical fiber, the interface medium having a second refractive index, wherein the first refractive index and the second refractive index are mismatched so as to adjust the optical radiation reflected from the reference interface such that the receiving electronics configured to receive optical radiation reflected from the reference interface and the target operate in a total noise range that is within 5 dB of a shot noise limit;
• wherein the catheter is further configured to connect with a processor configured to generate an image of the target based upon the optical radiation received by the receiving electronics that are operating within 5 dB of the shot noise limit.

A method of performing optical coherence tomography, comprising:

• transmitting optical radiation from a source through an optical fiber having a core, the core having a first refractive index;
• transmitting the optical radiation from the optical fiber through an interface medium, wherein the interface medium is in physical and optical contact with the optical fiber, the interface medium having a second refractive index;
• transmitting optical radiation reflected from the target and reflected from a reference interface along a common path in the optical fiber to a detector;
• receiving the reflected optical radiation at receiving electronics, wherein the first refractive index and the second refractive index are mismatched so as to adjust the optical radiation reflected from the reference interface such that the receiving electronics operate in a total noise range that is within 5 dB of a shot noise limit;
• and
• generating an image of the target based upon the reflected optical radiation received by the receiving electronics that are operating within 5 dB of the shot noise limit.