Methods and apparatus for the non-destructive detection of variations in a sample

1. A method of nondestructively detecting at least one constituent in an interior portion of a sample by THz imaging of at least a portion of the interior of the sample comprising:

introducing THz radiation to a sample;

receiving the THz radiation transmitted through the sample;

collecting spectral data of the received THz radiation comprising acquiring the image one pixel at a time and recording the spectrum of THz radiation at each pixel; and

generating a THz image of at least a portion of the interior of the sample by measuring one of THz power transmitted in a specific THz bandwidth, total transmitted THz power, or the frequency dependent phase of a THz wave, wherein the THz image contains information predictive of the presence or absence of a constituent, wherein the constituent is at least one of a void, anomaly, defect, density variation, or location in which a chemical or biological entity could exist or propagate.

2. The method defined in claim 1 further including the step of measuring amplitude and phase components of the received THz radiation.

3. The method of claim 1 wherein the sample is a cork.

4. The method of claim 1 comprising analyzing absorption spectra from a portion of the image.

5. The method of claim 1 comprising analyzing absorption spectra of at least one pixel of the image for determining at least one of whether a constituent is present in the sample, the identity of a constituent in the sample or the quantity or amount of a constituent in a sample.

6. The method of claim 1 comprising analyzing absorption spectra of more than one pixel of the image for determining at least one of whether a constituent is present in the sample, the identity of constituent in the sample or the quantity or amount of a constituent in a sample.

7. A method for nondestructively detecting a constituent in the interior of a sample containing cork, wherein the constituent is at least one of a void, anomaly, defect, density variation, or location in which a chemical or biological entity could exist or propagate, the method employing THz radiation to generate a THz image of at least a portion of an interior of the cork comprising the steps of:

introducing THz radiation to the sample;

acquiring spectral information from the THz radiation as a function of frequency through a Fourier transform of time-domain data; and

scanning the sample to generate an image one pixel at a time and forming a THz image by measuring one of THz power transmitted in a specific THz bandwidth, total transmitted THz power, or the frequency dependent phase of a THz wave.

8. A THz spectroscopy apparatus adapted to detect a constituent, selected from at least one of a void, anomaly, defect, density variation, or location in which a chemical or biological entity could exist or propagate, located in an interior of a sample comprising:

a source configured to generate THz radiation for introduction to the sample;

a receiver configured to receive THz radiation transmitted through the sample;

a device adapted to collect spectral data from the received THz radiation;

a means for producing a THz image of at least a portion of the interior of the sample by measuring one of THz power transmitted in a specific THz bandwidth, total transmitted THz power, or the frequency dependent phase of a THz wave; and

a device adapted to analyze an absorption spectra of at least a portion of the THz image.

9. The apparatus of claim 8 adapted to generate a THz pulse having a duration in a range from about 1 femtosecond to about 100 nanoseconds.

10. The apparatus of claim 8 further comprising at least one lens adapted to focus the generated THz radiation on the sample.

11. The apparatus of claim 8 further comprising at least one lens adapted to direct the received THz radiation to a THz detector.

12. The apparatus of claim 8 further comprising a beamsplitter and optionally a fiber optic pigtail.