Method and apparatus for optical imaging with means for controlling the longitudinal range of the sample

A system for performing optical imaging on a sample comprising:

• an optical radiation source;
• an optical path leading to said sample, said optical path terminating in a probe module, said probe module including means for controlling the transverse position on said sample at which imaging is being performed, said sample position being selectively changed by said means for controlling to scan the sample in at least one transverse direction;
• means for applying optical radiation through the optical path including the probe module to the sample;
• means for controlling an optical characteristic of the radiation source output to control the longitudinal range within the sample from which imaging information is being obtained;
• means for receiving optical reflections from said sample and responsive at least in part to said received reflections for generating an output having a frequency proportional to the length of the optical path to the longitudinal range in the sample being imaged;
• means for detecting said output;
• and
• means for processing the detected output to obtain a selected image of the sample.

A system for performing optical imaging and measurements on a sample comprising:

• a short coherence length optical radiation source;
• a reference optical reflector;
• a first optical path leading to said reflector;
• a second optical path leading to said sample;
• means for applying optical radiation from said source through the first optical path to said reflector and through the second optical path to the sample;
• means for altering the length of the second optical path to alter in the relative lengths of said optical paths in accordance with a predetermined velocity profile, having an instantaneous velocity V at each point on the profile;
• means for combining reflections from the reflector received through the first optical path and reflections from the sample received through the second optical path, the resulting combined optical output having interference fringes at length matched points on the two paths, the means for altering causing periodic changes in the longitudinal range position in the sample for the length matched points of the second optical path;
• a probe module terminating said second optical path, said probe module including means for controlling the longitudinal range focus for the module in the sample so that the longitudinal range focus is maintained substantially at said length-matched point as said point is periodically changed;
• means for detecting said output;
• and
• means for processing the detected output to obtain a selected image of the sample.

A system for performing optical imaging on a sample comprising:

• at least one optical radiation source;
• at least one optical reflector;
• a plurality of first optical paths leading from said at least one source to said at least one reflector;
• a plurality of second optical paths leading from said at least one source to selected transverse points on said sample;
• means for combining reflections from the at least one reflector received through each first optical path with reflections from the sample received through a corresponding second optical path, each resulting combined optical output having interference fringes at matched points on the two paths;
• and
• means for processing the combined optical outputs to obtain a plurality of images of the sample in parallel, said means including means for detecting each of said outputs and means for processing the detected outputs.

A method for performing optical imaging on a sample comprising the steps of:

• (a) causing short coherence length optical radiation to impinge on a reference reflector and on the sample through first and second optical paths, respectively;
• (b) altering the relative lengths of said paths in accordance with a predetermined profile;
• (c) selectively changing the transverse position on the sample at which scanning is being performed;
• (d) combining reflections from the reflector received through the first optical path and reflections from the sample received through the second optical path, the resulting combined optical output having interference fringes at length matched points on the two paths;
• detecting said output;
• and
• processing the detected output to obtain a selected image of the sample.