Coaxial fiber optical pyrometer with laser sample heater

A charged-particle beam microscope;

• the charged-particle beam microscope comprising:
• a pyrometer for use in the charged-particle beam microscope, the pyrometer further comprising
• a bidirectional light guide having a proximal end and a distal end, the bidirectional light guide further comprising an inner light guide and an outer light guide, the outer light guide surrounding the inner light guide and coaxial therewith;
• wherein the bidirectional light guide comprises a double-clad optical fiber, the double-clad optical fiber further comprising a core;
• so that the inner light guide of the bidirectional light guide corresponds to the core of the double-clad fiber, and the outer light guide corresponds to the inner cladding of the double-clad fiber;
• a directional coupler having a laser port, an analyzer port, and a distal port, the distal port optically coupled to the proximal end of the bidirectional light guide, the directional coupler configured to direct a backward-propagating light emitted from a sample and entering the distal port to exit at the analyzer port, and to direct a forward-propagating light entering the laser port to exit at the distal port,
• a laser optically coupled to the laser port of the directional coupler to provide forward-propagating laser light,
• focusing optics optically coupled to the distal end of the light guide and configured to focus the forward-propagating laser light onto the sample,
• collection optics optically coupled to the distal end of the light guide and configured to collect backward-propagating light emitted from the sample, and
• an optical analyzer coupled to the analyzer port of the directional coupler;
• the optical analyzer configured to measure at least one parameter of the backward-propagating light, and further comprising a processor configured to calculate a temperature of the sample from the at least one measured parameter of the backward-propagating light,
• whereby the sample is heated by the forward-propagating laser light focused onto it by the focusing optics, and the temperature of the sample is calculated from the at least one measured parameter of the backward-propagating light.

A method of measuring a temperature of a sample in a charged-particle beam microscope;

• the method comprising:
• aligning a heating beam to a predetermined position on the sample;
• irradiating the sample with the heating beam through a bidirectional light guide, where the bidirectional light guide comprises a double-clad fiber;
• collecting optical radiation from the sample;
• transmitting the collected optical radiation through the bidirectional light guide to an optical analyzer;
• and,
• analyzing the optical radiation to determine the temperature of the sample.