Optical source in microwave impedance microscopy

An optically driven material analyzer, comprising:

• an electrode tip which is positionable along an axis relative to a sample to interact with a sampling area of the sample;
• a first optical light source and a second optical light source emitting respective first and second optical beams at respectively a first optical frequency and a second optical frequency each corresponding to respective optical wavelengths of no more than 100 μm, at least one of the first and second optical light sources being wavelength tunable to vary its optical frequency of its emitted optical beam;
• a controller controlling the first and second optical frequencies of the first and second optical light sources to differ by an optical difference frequency in a microwave range of 100 MHz to 40 GHz;
• optics combining the first and second optical beams into a combined beam of radiation irradiating the sampling area;
• and
• microwave circuitry receiving a received microwave signal in the microwave range from the electrode tip and processing it to produce at least one electrical signal indicative of an interaction of irradiating radiation with the sample.

An optically excited materials analyzer, comprising:

• an electrode tip having an apex with a diameter about an axis;
• a flexible support projecting to a distal end thereof on which the electrode tip is mounted allowing the electrode tip to move along the axis to and away from a sampling area of a sample;
• a laser source irradiating the sampling area with a laser beam of optical radiation having a component with a wavelength of no more than 200 μm;
• and
• microwave circuitry (1) receiving detected signals from the electrode tip in a first microwave frequency range between 100 MHz and 40 GHz, and (2) producing at least one electrical signal indicative of an interaction of the component of the optical radiation with the sample.