Mapping ciliary activity using phase resolved spectrally encoded interferometric microscopy

An apparatus for performing phase resolved Doppler swept source spectrally encoded interferometric microscopy, comprising:

• a. a swept source laser (100), capable of generating a beam of laser light at a time-varying range of wavelengths at a repeated interval;
• b. an optical coupler (201), capable of dividing the laser beam into a sample arm (301) and a reference arm (302);
• c. a laser collimator (206), capable of producing a collimated beam of laser light, disposed to receive the light beam from the sample arm (301) of the swept source laser (100);
• d. a diffraction grating (401), disposed to receive the collimated beam from the sample arm (301), capable of diffracting light at varying angles according to wavelength, wherein the swept source laser (100) light is diffracted in varying directions in about proportion to its wavelength over time as the light sweeps through the repeated interval of wavelength, wherein the resulting sweep of light constitutes a fast scan in a first direction (701);
• e. a plurality of lenses and mirrors (400), disposed to direct the diffracted sweep of light onto a tissue sample (500), comprising at least one galvanometer mirror (402), wherein the galvanometer mirror (402) moves so as to reflect the light in a second direction (702) comprising a slow scan, wherein the second direction (702) is about perpendicular to the first direction (701), wherein the light is reflected back from the tissue sample (500) in a direction about perpendicular to both the first direction (701) and the second direction (702) through the plurality of lenses and mirrors (400);
• f. a detector (600), disposed to receive light reflected from the sample arm (301) and from the reference arm (302), wherein the light returned from the sample arm (301) and the reference arm (302) combine to form an interference pattern;
• and
• g. a processor (900), operatively connected to the swept source laser (100), the at-least-one galvanometer mirror (402), and the detector (600), wherein the processor (900) is configured to execute computer-readable instructions comprising:
• i. triggering the swept source laser (100) to begin a fast scan, during which the swept source laser (100), which triggers the processor (900), sweeps across a range of;
• wherein accordingly the laser beam main lobe sweeps across the tissue sample (500) in the first direction (701) due to the action of the diffraction grating (401);
• ii. controlling the galvanometer mirror (402) to rotate the mirror so as to move the beam in the second direction (702);
• iii. receiving an interference pattern from the balanced detector (600);
• iv. computing the Doppler shift of the light reflected from the tissue sample (500) from the interference pattern;
• v. computing the velocity of the tissue sample (500) from the Doppler shift;
• vi. repeating steps (iii)-(v) as the laser sweeps through the time varying range of wavelengths;
• vii. repeating steps (i)-(vi) as the galvanometer mirror (402) is moved in the second direction (702);
• viii. generating a two-dimensional image by assigning the computed velocity (response variable) to a pixel, wherein the location of the pixel corresponds to a specific position along the first direction (701) and the second direction (702) coordinate axes.