Apparatus and method for analyzing a sample

A method for CATM, comprising:

• providing a sample disposed on an EO crystal, wherein a sample surface of the EO crystal has a dielectric coating which is transmissive to THz and reflective to NIR, and the sample is disposed on the dielectric coating;
• transmitting a THz pulse through the sample and the EO crystal such that a birefringence of the EO crystal is changed according to the THz pulse;
• providing a probe beam to the EO crystal, wherein the probe beam reflects from the dielectric coating and co-propagates through the EO crystal with the THz pulse;
• measuring a difference in a polarization of the probe beam from a polarization of the reflected probe beam, the difference caused by the THz pulse in the EO crystal.

A hydration cell, comprising:

• a base plate having an opening therein;
• one or more walls disposed on the base plate and surrounding the opening;
• a window disposed on the one or more walls to form a chamber, wherein the window is transparent to THz light;
• a sample plate for holding a sample, the sample plate having an aperture with a diameter less than the smallest planar dimension of the sample, and wherein the sample plate is disposed in the opening of the base plate;
• a port in pneumatic communication with the chamber and configured to be connected to a hydration source, and wherein the base plate and sample plate are rotatable with respect to the port;
• a stage for holding a detector in contact with the sample plate;
• and
• an actuator for moving the stage such that the detector is spaced apart from the sample plate before rotation of the sample plate.