Agile imaging system

Abstract

An agile optical imaging system for optical coherence tomography imaging using a tunable source comprising a wavelength tunable VCL laser is disclosed. The tunable source has long coherence length and is capable of high sweep repetition rate, as well as changing the sweep trajectory, sweep speed, sweep repetition rate, sweep linearity, and emission wavelength range on the fly to support multiple modes of OCT imaging. The imaging system also offers new enhanced dynamic range imaging capability for accommodating bright reflections. Multiscale imaging capability allows measurement over orders of magnitude dimensional scales. The imaging system and methods for generating the waveforms to drive the tunable laser in flexible and agile modes of operation are also described.

What is claimed is: 
     
         1 . A wavelength tunable source for Optical Coherence Tomography (OCT) comprising:
 a vertical cavity laser (VCL), wherein the VCL generates a single longitudinal mode lasing output that is tunable over an emission wavelength range for generating wavelength sweeps at a sweep repetition rate, wherein the laser cavity free spectral range is at least as wide as the emission wavelength range;   wherein the VCL is capable of operating with a variable sweep repetition rate.   
     
     
         2 . The wavelength tunable source of  claim 1 , wherein the variable sweep repetition rate variation is at least 12%. 
     
     
         3 . The wavelength tunable source of  claim 1 , wherein the tunable source operates at a substantially fixed sweep repetition rate. 
     
     
         4 . The wavelength tunable source of  claim 1 , wherein the VCL is a vertical cavity surface emitting laser (VCSEL). 
     
     
         5 . The wavelength tunable source of  claim 1 , further comprising an optical amplifier;
 wherein the optical amplifier receives at least a portion of the single longitudinal mode lasing output.   
     
     
         6 . A wavelength tunable source for Optical Coherence Tomography (OCT) comprising:
 a vertical cavity laser (VCL), wherein the VCL generates a single longitudinal mode lasing output that is tunable over an emission wavelength range for generating wavelength sweeps at a sweep repetition rate, wherein the laser cavity free spectral range is at least as wide as the emission wavelength range;   wherein the VCL is capable of operating with a variable emission wavelength range.   
     
     
         7 . The wavelength tunable source of  claim 6 , wherein the variable emission range variation is at least 10%. 
     
     
         8 . The wavelength tunable source of  claim 6 , wherein the tunable source operates at a substantially fixed emission wavelength range. 
     
     
         9 . The wavelength tunable source of  claim 6 , wherein the VCL is a vertical cavity surface emitting laser (VCSEL). 
     
     
         10 . The wavelength tunable source of  claim 6 , further comprising an optical amplifier;
 wherein the optical amplifier receives at least a portion of the single longitudinal mode lasing output.   
     
     
         11 . An optical coherence tomography imaging system comprising:
 a vertical cavity laser (VCL), wherein the VCL generates a single longitudinal mode lasing output that is tunable over an emission wavelength range for generating wavelength sweeps at a sweep repetition rate, wherein the laser cavity free spectral range is at least as wide as the emission wavelength range;   wherein the optical coherence tomography imaging system has the characteristics of being able to operate by selecting between any two or more of the following modes:   i) imaging with a forwards sweep only;   ii) imaging with a backwards sweep only;   iii) imaging with both a forwards sweep and a backwards sweep.