Bond-selective full-field optical coherence tomography
A wide-field bond-selective optical coherence tomography (OCT) system and method for imaging a sample includes generating infrared light and directing the infrared light onto the sample to selectively heat the sample. Probe light is also directed onto the sample. A first actuator provides sample depth scanning with respect to a first objective in a reference arm of the system, and a second actuator provides sample depth scanning with respect to a second objective in a sample arm of the system. A detection system receives scattered probe light reflected from the sample. A change in the received probe light from the sample that is indicative of absorption of infrared light.
1 . A wide-field bond-selective optical coherence tomography (OCT) system for imaging a sample, comprising:
a source of infrared light for generating infrared light, wherein an intensity of infrared light is modulated between an on state and an off state, the infrared light being directed onto the sample, during the on state, to selectively heat the sample to a hot state associated with a first temperature, and the sample being allowed to cool, during the off state, to a cold state associated with a second temperature;
a source of probe light for generating probe light, the probe light being directed onto the sample;
a first objective in a reference arm of the wide-field bond-selective OCT system;
a second objective in a sample arm of the wide-field bond-selective OCT system;
a first actuator for providing sample depth scanning with respect to the first objective by actuating a reference mirror and a second actuator for providing sample depth scanning with respect to the second objective by actuating the sample, wherein the first and second actuators are synchronized for automatic coherence and focal plane matching; and
a detection system for receiving scattered probe light reflected from the sample, which allows detection of the hot state or the cold state of the sample, wherein the time period of the off state, predetermined based on the sample, allows for the difference between the first temperature and the second temperature to be the largest, such that the hot and cold states of the sample are differentiable by the detection system.
2 . The wide-field bond-selective OCT system of claim 1 , wherein the source of probe light comprises a light-emitting diode (LED).
3 . The wide-field bond-selective OCT system of claim 1 , wherein the detection system comprises a camera.
4 . The wide-field bond-selective OCT system of claim 3 , wherein the camera is a CCD camera.
5 . The wide-field bond-selective OCT system of claim 3 , wherein the camera is a CMOS camera.
6 . The wide-field bond-selective OCT system of claim 1 , wherein the infrared light is pulsed.
7 . The wide-field bond-selective OCT system of claim 1 , wherein the infrared light is mid-infrared (MIR) light.
8 . The wide-field bond-selective OCT system of claim 1 , further comprising a movable stage for providing controllable movement for scanning the sample.
9 . A wide-field bond-selective optical coherence tomography (OCT) method for imaging a sample, comprising:
generating infrared light, and directing the infrared light onto the sample, wherein an intensity of infrared light is modulated between an on state and an off state, the infrared light being directed to selectively heat the sample to a hot state associated with a first temperature, and the sample being allowed to cool, during the off state, to a cold state associated with a second temperature;
generating probe light and directing the probe light onto the sample;
providing a first objective in a reference arm of the wide-field bond-selective OCT system;
providing a second objective in a sample arm of the wide-field bond-selective OCT system;
actuating a reference mirror in the reference arm and the sample in the sample arm to provide sample depth scanning with automated and synchronized coherence and focal plane matching;
receiving scattered probe light reflected from the sample with a detection system; and detecting a change in received probe light that is indicative of absorption of infrared light from the sample, thereby allowing detection of a hot state or a cold state of the sample, wherein the time period of off state, predetermined based on the sample, allows for the difference between the first temperature and the second temperature to be the largest, such that the hot and cold states of the sample are differentiable by the detection system.
10 . The wide-field bond-selective OCT method of claim 9 , wherein the probe light is generated by a light-emitting diode (LED).
11 . The wide-field bond-selective OCT method of claim 9 , wherein the scattered probe light reflected from the sample is received by a camera.
12 . The wide-field bond-selective OCT method of claim 11 , wherein the camera is a CCD camera.
13 . The wide-field bond-selective OCT method of claim 11 , wherein the camera is a CMOS camera.
14 . The wide-field bond-selective OCT method of claim 11 , wherein the camera acquires images of received scattered probe light from the sample while an intensity of infrared light to the sample is modulated.
15 . The wide-field bond-selective OCT method of claim 9 , wherein the infrared light is pulsed.
16 . The wide-field bond-selective OCT method of claim 9 , wherein the infrared light is mid-infrared (MIR) light.
17 . The wide-field bond-selective OCT method of claim 9 , further comprising providing controllable movement for scanning the sample.
18 . The wide-field bond-selective OCT method of claim 9 , further comprising the step of creating a three-dimensional reconstruction of infrared absorbing regions within the sample.
19 . The wide-field bond-selective OCT method of claim 9 , wherein the probe light is modulated between an on state and an off state and is synchronized with the modulation of the intensity of infrared light, such that the probe light enters an on state when the sample heats up to the first temperature and when the sample cools down to the second temperature.
20 . The wide-field bond-selective OCT method of claim 9 , further comprising repeating the receiving and detecting steps at a plurality of relative phases between the sample and reference arms.
21 . The wide-field bond-selective OCT method of claim 9 , further comprising repeating the receiving and detecting steps at a plurality of wavelengths of the infrared source.
22 . The wide-field bond-selective OCT method of claim 9 , further comprising the step of producing a bond-selective 3D sectioned image of the sample.
23 . The wide-field bond-selective OCT method of claim 9 , wherein the sample is a biological tissue section.
24 . The wide-field bond-selective OCT method of claim 23 , wherein the sample has a thickness of greater than 5 micrometers.
25 . The wide-field bond-selective OCT method of claim 9 , further comprising repeating the receiving and detecting steps at a plurality of sample depths.
26 . The wide-field bond-selective OCT method of claim 9 , wherein the sample depth scanning has a range of at least 10 micrometers.
27 . The wide-field bond-selective OCT method of claim 9 , further comprising reconstructing a 3D chemical image of the sample.
28 . The wide-field bond-selective OCT method of claim 9 , wherein the sample is highly scattering.