Photon scanning tunneling microscopy

A method of photon scanning tunneling microscopy adjacent to a sample area on a surface, said method comprising:

• generating a near-field of light adjacent to the surface, the near-field having an increasing intensity in a direction normal to and towards the surface;
• sampling the near-field with a probe that receives photons tunneling between the surface and the probes, the number of photons being related to the intensity of the near-field at the position of the probe;
• detecting the photons received by the probe;
• producing an output signal that is substantially proportional to the number of photons received by the probe;
• scanning adjacent to a sample area with the probe in at least one direction;
• and
• monitoring the output signal as the probe moves to produce output information corresponding to light intensity distribution adjacent to the sample area.

A photon scanning tunneling microscope comprising:

• a surface on which a sample area is defined;
• means for generating a near-field of light adjacent to the surface, said near-field having a substantially exponentially decreasing intensity in a direction perpendicular to and away from said surface and, in the absence of a sample on the sample area, having a constant intensity throughout an area that is equidistant from the surface and is adjacent to the sample area;
• a probe for sampling said evanescent near-field, said probe receiving photons from said near-field that tunnel between said surface and said probe;
• a detector for detecting the photons received by said probe and producing a control signal that is proportional to the number of photons received by said probe;
• means for moving said probe and for scanning said probe through a pattern in the near-field adjacent to said sample area whereby the control signal varies as a function of the light intensity distribution adjacent to the sample area;
• and
• monitoring means for monitoring the control signal as said probe moves through the pattern to produce data corresponding to the light intensity distribution adjacent to the sample area.

A photon scanning tunneling microscope comprising:

• a source of laser light for providing a beam of laser light;
• an optical medium with a substantially flat surface on which a sample area is defined;
• means for introducing said beam of laser light into said optical medium, said beam striking an inner side of said surface at an angle that will produce a total internal reflection of said beam, said reflection producing an evanescent near-field adjacent to an outer side of said surface, said field having a substantially exponentially decreasing intensity in a direction perpendicular to and away from said surface;
• a probe for sampling said evanescent near-field, said probe being able to receive photons from said near-field, said photons tunneling between said surface and said probe;
• a tip on said probe formed into a point for receiving photons tunneling from said surface to said probe;
• a photomultiplier for receiving photons from said probe and producing an output signal that is proportional to the number of photons received by said probe;
• means for scanning adjacent to said sample area with said probe, said means further comprising:
• a x-direction controller for generating a x-direction signal, said signal having a magnitude that is representative of a x-distance in a x-direction which is parallel to said surface;
• a y-direction controller for generating a y-direction signal, said signal having a magnitude that is representative of a y-distance in a y direction which is parallel to said surface and perpendicular to said x-direction;
• x-direction piezoelectric ceramic bimorphs mounted to said probe which move said probe x distance in said x direction when said bimorphs receive said x-direction signal from said x-direction controller, said bimorphs being operable for moving said probe a controlled distance smaller than the wavelength of the photons in said field;
• and
• y-direction piezoelectric ceramic bimorphs mounted to said probe which move said probe said y-distance in said y-direction when said bimorphs receive said y-direction from said y-direction controller;
• said bimorphs being operable for moving said probe a controlled distance smaller than the wavelength of the photons in said field;
• a z-direction controller for generating a z-direction signal having a magnitude that is representative of a distance in a z direction, said z direction being normal to said surface;
• z-direction piezoelectric ceramic bimorphs mounted to said probe which move said probe said z-distance in said z-direction when said bimorphs receive said z-direction signal from said z-direction controller;
• means for monitoring said output signal of said photomultiplier tube and for controlling said z-direction controller whereby the output signal of said photomultiplier tube is held at a substantially constant level as said probe is moved directions parallel to said surface and whereby said z-direction bimorph moves said probe further away from said surface when the output signal of said photomultiplier tube increases and said z-direction bimorph moves said probe closer to said surface when the output signal of said photomultiplier tube decreases and the distance of said probe from said surface varies as a function of the interaction of said sample area with said surface;
• and
• means for producing an output signal corresponding to the x, y and z direction signals.